This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------ Here find many users' practical tips for casting metal. There may also be some tips on casting other materials. Please note: Casting of metals is a particularly dangerous operation where appropriate safety precautions must be taken at all times. There is also some information related to casting in the text file "Gears General". If you got to this file directly from my HOME PAGE, return there by using your browser's back button. BUT if you came to this file as the result of a web search engine, see many additional files on my home page Machining and Metalworking at Home http://www.janellestudio.com/metal/index.html SAFETY WARNING BEWARE: DO NOT ASSUME that any subject matter or procedure or process is safe or correct or appropriate just because it was mentioned in a news/user group or was included in these files or on this site or on any other web site or was published in a magazine or book or video. Working with metals and machinery and chemicals and electrical equipment is inherently dangerous. Wear safety devices and clothing as appropriate. Remove watches, rings, and jewellery -- and secure or remove loose clothing -- before operating any machine. Read, understand and follow the latest operating procedures and safety instructions provided by the manufacturer of your machine or tool or product. If you do not have those most recent official instructions, acquire a copy through the manufacturer before operating or using their product. Where the company no longer exists, use the appropriate news or user group to locate an official copy. Be careful -- original instructions may not meet current safety standards. Updated safety information and operating instructions may also be available through a local club, a local professional in the trade, a local business, or an appropriate government agency. In every case, use your common sense before beginning or taking the next step; and do not proceed if you have any questions or doubts about any procedure, or the safety of any procedure. Follow all laws and codes, and employ certified or licenced professionals as required by those laws or codes. Hazardous tasks beyond your competence or expertise should also be contracted to professionals. Let's be really careful out there. (c) Copyright 2003 - 2015 Machining and Metalworking at Home The form of the collected work in this text file (including editing, additions, and notes) is copyrighted and this file is not to be reproduced by any means, including electronic, without written permission except for strictly personal use. ========================================================================== Date: Fri, 08 Dec 2000 16:31:02 -0000 From: "Greg Miller" Subject: Machinist's Red Plastic.... I have been using some red plastic(wax)(machinist's) for milling (Taigcnc) jewellery pieces. The melting temperature is 500F which allows us to vulcanize(make rubber molds) at 350F without melting the model. This allows us to skip casting our models before they are cast in pewter or zinc/aluminium. I would prefer to pour my own sheets and blocks to a given thickness which would require less cleanup when removing the model from the milling material. Does anyone have an idea what the ingrediants of this material are? I have already tried materials like HUMW, Teflon, HDPE, etc. The HUMW will dull a sharp edge very quickly. We are also going to try to make our own sheets or material from 100% tin which is also commonly used by the model makers in the fashion jewellery industry. I might have tended this question before....still looking. Thanks Greg, ------- From: "Martin R Gutzmer" Date: Sun Jul 8, 2001 11:27 pm Subject: Casting Bronze I am new to lathe and metal working and am trying some casting, and would like to try some in bronze - have done some in aluminum. Question 1. Where do you get a thermometer that will tell you the temp of metal in a crucible? Question 2. How do you cut a semi-parabolic curve, such as the shape of a bell on a lathe? (Craftsman 109) Thanks, Martin ------- From: S1 Date: Mon Jul 9, 2001 1:45 am Subject: Re: [atlas_craftsman] Casting Bronze Look for a foundry supply place, and you will be able to buy a pyrometer. Often, you don't need a pyrometer, because if you look into the crucible and see a little swirling action in the molten metal, it is ready to pour (wear appropriate face protection when doing this). In the foundry I used, we used the pyrometers in the mold heating kiln to make sure the molds were the right temperature because the heat in furnace where the metal is melted will destroy the best pyrometers after only 5 or 6 pours. You pour bronze at 2100 degrees F, that kind of heat will quickly break down most things, except the toughest ceramics. Gabe ------- From: Ronald Thibault Date: Sat Jul 14, 2001 10:15 am Subject: Re: [atlas_craftsman] Casting Bronze Martin; Check out http://members.nbci.com/HWilkinson/index.htm This is the main site for the foundry list I'm on. Very useful site and lots of good info and help for those of us who wish to do casting at home. Ron Thibault North Augusta, SC USA Builder Miinie #2 Captain R/C Combat Ship USS Arizona http://pages.prodigy.net/thibaultr/ ------- Date: Tue, 29 Jan 2002 09:30:16 -0000 [taigtools] From: "joulesbee" Subject: Re: milling cutters for wax >> I am looking for any info on very small milling cutters for wax. Especially any info on making homemade micro cutters for wax. Such as what kind of profile you use. What kind of fluting should I use. i would like to use these cutters for making rings with engravings and piercing. << "JAMES BEGGEROW" wrote: > Try ganoksin.com also I have a friend that makes rings using the lost > wax process He makes his wax masters on a cnc machine. Jim Try using the dremel tungsten carbide burrs. I use the finest cutters I can find. They give a reasonable finish on wax, but the wax still needs to be burnished if you are looking for a high level finish. I use machinist wax on a Roland Modela, with the above tooling, plus some normal 3mm cnc cutters. Joules ------- Date: Tue, 29 Jan 2002 12:32:10 -0000 From: "Andrew Werby" Subject: Re: milling cutters for wax Take a look at http://www.micro100.com/ Their miniature carbide endmills work well on machinist's wax. I wouldn't try making this type of cutter at home though. For that, I'd make the profile I wanted on a lathe (lacking that, chuck up a piece of drillrod in a flexshaft or Dremel, and hold it against a file or piece of sandpaper until you get the shape you want) then with a grinding wheel remove half the diameter, so the cutting part is D-shaped in section. You don't really have to make flutes. Andrew Werby www.computersculpture.com ------- Date: Tue, 29 Jan 2002 17:41:49 -0800 From: "JAMES BEGGEROW" Subject: Re: milling cutters for wax Steve, I called My jeweler friend and He buys his tools from a company called Bits&Bits; their website is www.bitsbits.com He uses pyramid type with a 15 deg included angle He also uses the standard engraving cutters. The type of wax you use also will determine the type of cutter to use. My friend makes his living making custom jewlery by the lost wax casting. HTH. jim ------- Date: Thu, 31 Jan 2002 10:49:33 -0000 From: "Andrew Werby" Subject: Re: Looking for wax I use the blue machinist's wax from Freeman Supply (www.freemansupply.com) In bulk, it goes for about $4.50/lb. That gets you randomly assorted big blocks. I've had pretty good luck remelting it, although it melts at a higher temperature than normal wax, stays a bit more viscous, and shrinks quite a bit. It's much better in this regard, though, than the green carving wax jewelers use- and it's cheaper. Andrew Werby www.computersculpture.com ------- Date: Wed, 27 Feb 2002 23:24:53 -0000 From: "ddolata" Subject: Re: machinist's wax The company I work for makes a proprietary machinable wax better than anything we could find on the market. We use it to make prototypes for precision investment casting of stainless. If anyone is interested I should be able to sell some small amounts. (hope this doesn't sound like a shameless plug, 'cause it's not :-) David ------- Date: Thu, 28 Feb 2002 00:00:37 -0600 From: "David Dolata - PMI" Subject: Re: Re: machinist's wax From: Edwin S. Katz To: taigtoolsx~xxyahoogroups.com >I would be interested in obtaining some more information. Thanks, Ed Ed, What size chunk would you like? If you need larger quantities we would have to make a special batch. I probably have 20 pounds on hand. If you send me your address privately I'll get a price together including shipping. I would be willing to send out small samples to anyone for little more than the cost of the shipping as long as they gave me some type of feedback on how it worked for them, especially if they can compare it to other waxes. I wouldn't mind marketing this if there is any real interest, it is good stuff. David Dolata ------- Date: Sat, 27 Jul 2002 14:30:17 -0000 From: "variousgroups" Subject: Mold Making Tips -- looking for Has anyone any experience they would gladly share building small, simple molds for low-temperature metals -- for example white metal and pewter -- using the Sherline mill? Tapered end mills are surely a must, as are also, I would imagine, rounded end mills for defining the intersections of planes -- all so that the molded (and cooled!) piece can be extracted and/or ejected easily. By small I mean that the finished piece will have dimensions not more than 3.5" for length, and 1.25" for both depth and width. Simple means no undercuts; all straight pull. Mike ------- Date: Sat, 27 Jul 2002 11:13:26 EDT From: madcadderx~xxaol.com Subject: Re: Mold Making Tips -- looking for I would be glad to help with the mold you are thinking about. I have been designing & building molds for almost 30 years. Do you have a part in mind, or on paper. Do you know what machine you will run the mold in or are you thinking of a minimal hand type operation? You will need to know the material you want to mold, so you can increase the dimensions for shrinkage. Do you have a cnc set up or are you going to step off all the tapers or do you want to use tapered end mills. If it is for fun I can tell you how to do most of it with standard end mills and a calculator. Some of the set ups used before CNC mills came along are incredible. The most elaborate I ever saw was a dividing head(holding the work piece) clamped to a tilt table clamped to a set of cross slides clamped to a rotary table clamped to the mill table. To top it all off the guy was doing the cutting with a J head mounted on his Bridgport. Send a part drawing and let's look at it. John Murphy. ------- Date: Sat, 27 Jul 2002 12:03:08 -0400 From: "Van Lupo" Subject: RE: Mold Making Tips -- looking for I would recommend a book I found some time ago titled "How to Cast Small Metal and Rubber Parts" by William A. Cannon. Published by TAB Books, ISBN 0-8306-0414-6 (pbk) $15.00 in paper back. This book is very informative on the subject of small molding and presents many different ways to accomplish making metal parts using molds. If also shows how to build a small Furnace for only $30.00 using basic readily available materials. Van ------- Date: Sat, 27 Jul 2002 19:02:57 -0700 From: "Marcus & Eva" Subject: Re: Mold Making Tips -- looking for Hi Mike: A way you may want to consider, is lost wax casting rather than permanent metal molds. Lost wax allows much more forgiving moldmaking techniques and will produce very fine levels of both detail and accuracy. Permanent steel molds for metal casting typically require hotwork steels such as H13 to minimize mold erosion and consequent part sticking. I would not seriously consider a permanent mold (diecasting or otherwise) unless I was looking at amortizing the mold over 5000 parts minimum. If you want more details on lost wax casting, both jewellers and dental lab technicians use this technique extensively and their methods are well documented. Basically, a pattern is made from the material of your choice, and a silicone or vulcanized rubber mold is made using this master. A low pressure wax injector is used to fill the mold, and the finished waxes are pulled from the mold, sprued and embedded in a ceramic slurry called "investment". The wax is steamed and burned out of the mold and the metal is then cast into the hot mold either with a vacuum casting machine or a sling caster. None of the gear is sophisticated or expensive, in fact, it can all be easily homemade (and often is!!) The technique allows you to easily expand the range of metals you cast, because the investment is used only once per casting, so by merely changing investment, you can cast all kinds of metals. Cheers Marcus ------- Date: Sun, 28 Jul 2002 10:13:11 -0500 From: John Thompson Subject: Mold making tips As mentioned, use straight end mills for roughing, then tapered and ball endmills to finish. I'm a mold maker for thermoforming molds, but we also use CNC machines and MasterCam :) You will want some draft in your sidewalls so the parts will come out. John ------- Date: Sun, 28 Jul 2002 16:43:09 -0000 From: "variousgroups" Subject: Re: Mold making tips The prototype project I'm involved in calls for making about twenty molded pieces, at least at this stage. I'd like to cast them in a metal that will take a high polish or that can be zinc/chrome plated, something similar to white metal or pewter. The is no fine detail to reproduce, just basic form and overall dimensions, accuracy of 0.01" more than enough. Plaster molds seem to be one possibility, although they tend to break and need to be heated before use to drive out the residual water. Usable plaster molds could be fairly easily made from a Delrin prototype of the item machined on a Sherline mill, which, in terms of size and precision, is ideally suited to the project. But I am thinking that a small aluminum mold might be fairly easy to make, and would offer the advantage of durablility. About tapered end mills my basic question concerns the taper itself. 1/2 degree somehow seems too little, but 1 degree might be okay. Any advice here would sure be appreciated! The intersection of the sides with the bottom of the cavity would be left sharp were only end mills used, straight or tapered, and so I thought that these lines of intersection should probably be finished using a ball end mill. Your advice appears to second my hunch. The cavity depth is just slightly over 1" -- without the drawings in front of me I believe to recall that it's 1.02", and so there seems to be a need to use long end mills. I may be able to shave this dimension down to 1". Another advantage of an aluminum mold over a paster mold would appear to be the ability to introduce simple ejectors fairly easily with the aluminum. Any suggestion as to the best kind of aluminum to use?? Or should I use a soft steel and just go very slowly with the machining. Lost wax appears to be a costly method inasmuch as each piece requires its own wax form, which then gets destroyed and has to be remade, if I understand the process correctly. There is a similar process called "lost foam" that is said to be cheaper and good for low-detail levels. Best, Mike PS: I write "appears" and "seems" pretty often because I'm uncertain what the answer is but somehow feel close to being on the right track. ------- Date: Mon, 29 Jul 2002 09:40:47 -0500 From: John Thompson Subject: mold making tips 6061 T6 aluminum would be a good material to use. Its common, and durable enough for what you have in mind, casting relatively few pieces with a low temp metal. Don't worry about getting "long" cutters. You can always let the cutters stick out further, since you wont be making cuts the full depth of the flutes. Thinking about it though, in Sherline size terms, the cutters would indeed be long. Except in very rare occasions, we don't have draft of the cavity molds of less than 3 degrees, but then our molds are not for cast pieces. Tapers of 3, 5, 7, and 10 degrees are common in cutters, and so are more cheaper. I'm not too clear about what you are saying about the base, so I won't comment. "Lost foam" is a method used for making 1 up fiberglass parts. Basically you make a foam "plug" in the shape of what you want, glass it over, then melt out the foam with acetone or even gasoline! Not what you want! The lost wax method isn't really expensive, just time consuming. Its very similiar to the plaster mold idea you proposed. You make a master mold in which you pour the wax parts. You then coat the wax parts in clay (allowing for pour and vent holes), fire the clay which also melts the wax, then pour the molten metal in your fired clay mold. Break off the clay, and there is your part. The master mold is simply for the wax parts. All in all, without seeing your drawings, I'd say go with the aluminum mold, even though it will be more durable than 20 parts. John ------- Date: Mon, 29 Jul 2002 11:25:44 -0400 From: "Ron Ginger" Subject: RE: Mold Making Tips Lost wax patterns can be made directly- look in a jewelery catalog and you will see many shapes of wax- rod, sheet, rings, etc. A jeweler will take the wax and form it into a pattern that is then cast for a one-off item. I have considered this for one-off parts for model engines. It does save the step of the rubber mold and wax injection, but at some risk to the single pattern. I heard one story of a box of such one-offs in the window of the car enroute to the casting place. When he arrived he had a nice puddle of wax. You could build up the part from the various shapes, and eaisly melt on extra wax to build up fillets, or lugs, or any projection to a part. It's easy to carve and easy to shape. There are many places that will invest your wax and cast a part, and the cost for that is not high- to them the part is just a lump of wax and some ounces of metal, they dont care if its a model engine or jewelery. ron ginger ------- Date: Wed, 11 Dec 2002 09:22:14 -0600 From: "Ray Ethridge" Subject: Re: You'd need a foundry to feed that beast![METAL_SHAPERS GROUP] The American Pathfinder lathe I just bought had a legitimate business need, I make a part for the oil industry that is 1 11/16" OD and I had no way to put it through the headstock on my Rockwell. But the big shaper is purely for fun, I just like to watch them go back and forth and scoop off metal. Lots of metal. If it never makes a useful part that is OK, but I bet I can find all sorts of uses for it. Maybe there is a some wanting to have the biggest shaper on the block, but I already have the biggest shaper that I know of for about a 5 mile radius. Shapers are a lot better than big dogs (I have them too), if you are not using the shaper you don't have to feed it! As far as the foundry goes, I have a small scale one, I can cast parts up to about two quarts worth of metal if I had to. I am using some homemade ZA12 for most of my castings, the slick thing about that is that it doesn't seem to matter wether I use ingots or chips, it casts the same. So I can cast big things, turn them into chips, then recast the chips and start over again! Still, it would take a lot more than what my turkey fryer can turn out to feed the "big'un". Ray Ethridge ------- Date: Wed, 16 Apr 2003 17:41:59 -0400 From: "Quale, Robert" Subject: RE: Re: Where to buy tooling for my 10" shaper: After the Wedding is... "dreilanderecht" wrote: > Surely someone could use their vice as a pattern to make you up a set > of castings...seems a legitimate approach for something that was > supplied as a kit in the first place. You need to build up the areas > that will be machined of course, with something temporarily stuck on, > like heavy card. > I'm busy making a pattern for the Ammco vice base, might make up the > patterns for the between centres attachment too while I am about it. > regards John When you cast it, what are you going to cast it out of? I wonder if aluminum is strong enough? I have never done iron, I wonder how that would work out. ------- Date: Wed, 16 Apr 2003 22:09:41 -0000 From: "Art Volz" Subject: Cast It of What??? How About ZA-12 Robert--Consider using ZA-12 with physical characteristics comparable to that of some cast irons: http://www.eazall.com/gravity-casting.htm ZA-12 melts at lower temps than Aluminum and can be gravity cast into sand/petrobond type molds or--IF YOU TOTALLY BAKE OUT THE WATER--in 2 piece (or more) plaster molds. Jaw faces remain steel plate. Might want to consider steel plate facing for the frame slideways, although ZA-12 has excellent anti-friction bearing characteristics. This is something you can cast in your back yard--in a "Turkey Nuker" as Ray E. does on moonless nites atop C. Hill --with minimum, and home-brewed, equipment. While Ray E. conjures-up his own private label brand of ZA-12-- a bat's wing here, a bit of amorous dried cockroach there--there is a company in southwest Canada that will sell small quantities of reasonably priced ZA-12 to hobbyists like us. If you're interested, I'll re-look for their web site. Art (Houston) ------- Date: Wed, 16 Apr 2003 17:36:54 -0500 From: "Ray Ethridge" Subject: Re: Cast It of What??? How About ZA-12 Robert, You better be careful with the casting operation though, it is every bit as addicting as running a shaper! I agree with Art, I think ZA-12 is a fantastic material to cast, and unlike aluminum, it is a dream to machine after it is cast. Ray Ethridge ------- Date: Wed, 16 Apr 2003 22:39:55 -0000 From: "dreilanderecht" Subject: Re: Cast It of What??? How About ZA-12 I have a cooperative foundry not too far away (well, 300 miles...) who will do castings from loose patterns for amateurs at reasonable rates... the ones for my steam launch engine worked out at around fifty New Zealand Dollars a piece, which is only about 25 US$. Quite reasonable compared to buying a big enough lump of solid and carving it out. It is possible to cast iron at home, although maybe not legal depending on zoning etc. You are not going to be able to kid the neighbours that it is just a barbeque anyway. regards John ------- Date: Wed, 16 Apr 2003 19:28:34 -0500 From: jrw Subject: Re: Cast It of What??? How About ZA-12 Art: The Zxx alloys may be as strong as the cast iron parts and easy to machine, but there will be a big problem with chips imbedding into the material. I use aluminum for fixtures in my mill and have to be careful with chips. Joe W ------- Date: Wed, 16 Apr 2003 23:44:55 -0500 From: "Ray Ethridge" Subject: Re: Cast It of What??? How About ZA-12 I make mine from scrap diecast zinc, aluminum cans and copper wire. It only costs me about $0.40 per pound. I also use petrobond, it casts like a dream in petrobond. Ray Ethridge ------- Date: Thu, 17 Apr 2003 12:23:02 -0000 From: "John Odom" Subject: Casting I have a foundry for Al, Zinc alloys, and bronze. See my webpage: odomsite.com go to the "School art project" link. I also have a local foundry that has done some short runs for me in Iron. John Odom ------- Date: Thu, 17 Apr 2003 19:26:40 -0000 From: "Art Volz" Subject: Casting Supplies, Petrobond, ZA27 (NEW!!) & Pattern Making Books Since we've developed some interest in casting, let me add a few more morsels (orts?) for consideration-- An excellent source of "this & thats" for home-brew casting stuffs is http://www.budgetcastingsupply.com . I've bought from them as have others from the Houston club with excellent results. ( http://homemetalshopclub.org ). They have all of those little thingees, and big ones too, for which the queries are always made: "Where in heck do I find that? It's not in the ENCO or MSC catalog." Well, it's probably in Budget's catalog, and on-line. Joe W. has a point about cutting particles possibly embedding (like a CNN reporter in a Russki HUMVEE, or as in one of Mario's lead laps) in a zinc alloy vise casting, but only if the vise material is softer than the cutting chips. With appropriate & timely applications of the machinist's brush, these chips should pose no hazard. While a zinc alloy can make a good vise it is not a one-for-one design transformation: considerations and design changes must be made to adapt a vise design to use a new material. The vise jaws of steel plate would remain the same. Provision for putting steel slider plates atop the frame slideways should be considered, not necessarily for slideway wear protection, since the ZA alloys are excellent bearing materials, but for extablishing a squared machined surface on which to place the parallels with consistent accuracy. The swivel base and swivel plate (the latter located and affixed to the frame with locating pins and machine screws like shown in the AMMCO vise dimensioned drawings in "files") should be made of off-the-shelf steel plate, turned to size on your 10-inch lathe faceplate (max plate circular diameter = 10-inches--max square plate = 7-inch x 7- inch). (Interestingly, a Lewis-size base plate can be accommodated readily on my 10-inch Logan/Monkey-Ward lathe.) Another design change would be like the one I made in my Lewis-type 7-inch vise mockup/working-model: I used a captive ACME 5/8-8 LEFT-HAND nut for strength, simplicity, and economy, as such a nut is only $1.70 from Wholesale Tool whereas an ACME 5/8-8 LH tap is $85.71. Note also that Budget Castings Supply has ingots of Zinc-Aluminum-27 (ZA-27) for $2.50 per pound shipping included. A Lewis-7 type vise, with steel plate jaws, ACME screw, swivel base & base plate of steel, shouldn't take more than 2 x 18 lb ingots of ZA-27 or $90 worth. If you screw-up, or don't like your "masterpiece", simply re-melt the devil. Of course, if you have a source of zinc scrap like Ray E. has found (a veritable mother lode glory hole) do it at 40 centavos/lb or about 15 GW's per vise casting set. And then, you just can't have enuf books...especially about making patterns. Check out http://lindsaybks.com for copies of their excellent reprinted books on pattern-making--ask that they mail you their latest catalog. I own all of their offered pattern making books. Each time I develop a new potential casting I consult these books, and others in my library, both to see if "I done it right" and if "I done it wrong." Also look for Vince Gingery's new Lindsay book about casting your own crucibles; that's a book that's on my next order list. And then, there is the dreaming: what I need is a simple construction plan for making a small, readily transportable, muller. Not a huge one--I don't need to mull the petrobond kit and olivine sand in 100 lb batches--four 25 lb batches would be just fine. Remember, that this is a MULLER and NOT a MIXER as a MIXER won't MULL!! So...mull it over folks.... Hmmmmmh???? I wonder if I sawed this 25 lb old style non-OPD valve propane tank in two...would it make a muller?? The hard part is cutting it in two: first let it stand for a week with the valve wide open prior to filling it with H2O (oh, how long it takes!!) to get the rest of the EXPLOSIVE gas out. And then...when I'm POSITIVELY sure...a series of closely spaced drilled 1/8-inch holes at its "equator line"...left set again/refilled again with water...and the holes are then connected via appropriate wiggling of the drill bit under power. Then...the half hour session with the sabre saw and several good quality HSS blades.... I wonder...????????? There is also the Hern gray iron foundry up in the Northwest. Their site is: http://www.hernironworks.com They have an excellent reputation and will do one-off's in CI for hobbyists. They also have castings from which you can make your own bowling-ball mortar. They used to have a short film clip on site showing a bowling ball enroute to Saddam with Luv n' Lots of Smoke. Art (Mullin' in Houston) ------- Date: Fri, 18 Apr 2003 15:57:29 -0500 From: "Ray Ethridge" Subject: Re: Re: Casting Supplies, Petrobond, ZA27 (NEW!!) & Pattern Making Books Joe: The reason I ended up with ZA12 is that I spent almost 6 months trying to cast parts out of zinc diecast materials with minimal success, at least on the larger parts. As it turns out the normal zinc diecast materials do not sandcast very well at all, they are very prone to shrink voids. Once zinc is alloyed to a standard sand casting alloy it does cast very well, but I don't think you will be happy with the standard die cast materials for sandcasting if you are working with anything with much of a cross section. As far as the composition of the metal, if it is truly a zinc diecast there is a real good probability that it is a 4% aluminum zinc alloy, possibly with a small amount of copper in it. Ray Ethridge ------- Date: Sat, 19 Apr 2003 03:34:37 -0000 From: "joe mama" Subject: Re: Casting Supplies, Petrobond, ZA27 (NEW!!) & Pattern Making Books thanx for the feedback, ray & mario. had i done my homework before asking, i would have found in my fine manual of lathe operation that zamak is composed of al, mg, zn, & cu with no proportions given & and a pic of a monster diecasting machine captioned to indicate that tons of pressure are required to form zamak parts. further research into my handbook of chem & phys (50's vintage) yields zamak 2 aka ASTM alloy XXI, aka SAE alloy 902 = 93Zn, 4Al, 3Cu, 0.05Mg. Sp Gr 6.8, thermal expansion coefficient 37.7/deg. C, & melting point 379.5 deg C. http://www.tridentalloys.com/za12comp.htm gives proportions of za12 as 88Zn,11.1Al,0.9Cu,& 0.025Mg. i had this site bookmarked from a google prompted by a post in one of the mini lathe groups. same search BTW that led me to this group several months ago. have read most posts here since then & would have read the whole archive if it wasn't so big & if i wasn't trying to follow 29 other yahoo groups. i feel like know most of you guys already. between my last post and this one i took measurements of the gearing arrangement in the atlas 12 apron linking handwheel to rack to make a pattern for a duplicate for another atlas 12 i am putting together for a friend. brain hurts from all these run on sentences. my apologies if yours hurts too.back to percolating mode to let the dregs settle & the bubbles escape. later, joe b ------- Date: Sun, 20 Apr 2003 07:39:12 -0000 From: "dreilanderecht" Subject: Re: VISE for 7" Atlas Shaper I now have a pattern for the Ammco vice as featured in the files section here. I hope to send it off to the foundry with some other stuff in the next week or two. Anybodies guess how long the foundry will take (Loose patterns are a job for idle moments) or what it will cost, although probably well under $25 US for the piece. Then if anyone in the USA wants one there would be postage...I dunno what it will weigh yet, but 5kg would cost about $40 US, economy post. [NOTE TO FILE: REMEMBER JOHN IS IN NEW ZEALAND.]So I guess you would have to want to make it pretty badly to pay that sort of price, but if anyone is interested, and especially if you can think of any ways of delivering such a thing that don't cost more than the item did in the first place, let me know, because the foundry would be just as pleased to do half a dozen as one. The only really good news is that they do excellent castings, very nice to machine. I'm also well on the way with two patterns for the Ammco dividing attachment. That too might be something that other Ammco or seven inch shaper owners would enjoy making. While I'm about it I am thinking of using the downfeed for my big Alba as a pattern to cast a new one, it might be easier than machining off the broken area and making a part to fit. Especially since most of the gib screws are broken off an immovable. OK for now, but too bad if I ever need to adjust it. I've already made the pattern for the missing support leg casting. regards John ------- Date: Sun, 20 Apr 2003 13:26:15 EDT From: anthrhodesx~xxaol.com Subject: Re: VISE for 7" Atlas Shaper In a message dated Sun, 20 Apr 2003, John writes: << --- I'm also well on the way with two patterns for the Ammco dividing attachment. That too might be something that other Ammco or seven inch shaper owners would enjoy making. >> Is there a photo of this dividing attachment available? I'm very interested. As far as the broken off gib screws are concerned, if nothing else works you should be able to trepan them out, then retap the holes for larger set screws. Not to suggest that a new casting is a bad idea. Anthony Berkeley, Calif. ------- Date: Sun, 20 Apr 2003 23:36:07 -0000 From: "dreilanderecht" Subject: Re: VISE for 7" Atlas Shaper I'll bear in mind the idea of sending the patterns stateside later, this would make sense. I should have said, I don't have any dreams of making money by selling shaper parts, this is strictly noncommercial. There are pictures of the dividing attachment in the Ammco instructions, which can be supplied by several group memebers...I might try to scan the relevant picture and drawing later. The drawing in the parts section is not sufficiently detailed to let us make an exact facsimile, although I am trying to make the patterns as close as possible in appaearnce to the original. But lacking the details of the turned parts, there will be a certain amount of guesswork. However, we should be able to make a very useful little attachment. One feature that I think could be added without too much trouble is a worm feed as a replacement for the drilled plate and disk. This allows you to do a rotary feed, so you can make parts which are partly rounded and partly flats or whatever. The original dividing arrangement is just direct division from the plates, which is OK for most things, provided you have plenty of plates. Which will be a problem for anyone who wants to make it and doesn't have another dividing arrangement available to make the plates. You can easily make one to match each lathe change wheel you happen to have, but for any really odd numbers you want a proper dividing head with a worm. I guess I could get the old screws out of the downfeed as you say, but since one corner was knocked off I am tempted to go the whole hog and make a new one. regards John ------- Date: Wed, 23 Apr 2003 21:05:49 -0000 From: "dreilanderecht" Subject: AMMCO Dividing Attachment (Was Re: VISE for 7" Atlas Shaper) Hi Anthony: I have posted a picture in the Ammco section of my pattern, as it was before last night, I have since added a little more to the patterns. But the picture will give you an idea what the attachment is like. The ruler is one foot. As you will see, the whole thing is a little like a tiny lathe...the base piece gets a T slot machined in it, and the small headstock can slide along the base and be locked in any position with the T bolt. Both head and tailstock have centres, and the headstock has a pin to engage with a dividing wheel, which is what the lump on the near side of it is for. If you want the Ammco manual, I could post you a copy although it might be better to wait until I do a bit more work on my CAD drawing of the attachment. This will show dimensions for the parts, which of course may not exactly match the way Ammco did it, but will be workable and makeable. (I hope!) You would need to send a postal address to me at giolw9r4vh001 at sneakemail.com As you will see, the principle of the attachment is simple enough and it would not be all that hard to fabricate something suitable without the castings. An improvement would be to arrange to be able to have a worm feed instead of the dividing disk. Even if you don't use the worm for dividing which is much more versatile than direct dividing, it is handy to be able to rotate the job for a feed. This lets you make things where part of the job has a circular arc profile while other parts are flat. I have already done this with a Vertex dividing head and tailstock on a bigger shaper, and it is a handy capability to have. regards John ------- Date: Wed, 20 Aug 2003 11:45:06 -0600 From: "David Rygmyr" Subject: RE: Wax I just made my first project in wax; I machined the rough on my Sherline mill and then finished it by hand. (It was an O scale anvil.) I used green Matt wax and thought it performed pretty well. I'm not the guy to ask about feed speeds, however. Regardless of material, I work s-l-o-w and take shallow cuts, whereas I know guys who are always looking for "the line" when it comes to feed speeds and cutting depth. --Dave Rygmyr Oso Publishing Co./Evergreen Hill Designs (www.osorail.com) P.O. Box 1349 Hamilton, MT 59840 Phone:(800)337-3547 Fax:(406)375-7559 ------- Date: Wed, 20 Aug 2003 19:19:40 -0000 From: "Glen Reeser" Subject: Re: Wax I've machined a lot of wax on my Sherline. I make cast silver pen barrels for the fountain pens I make. Not the kit pens, scratch built pens with rubber ink sacs and lever fill mechanisms. Cutting triple lead threads on caps and barrels is a bit tricky on a Sherline. Anyway back to wax. I found the green wax to be very forgiving of feed rates compared to some plastics I have turned. Heat build up on the tool can melt the surface and wreck the finish on plastic, but I never had a problem with wax. The one annoying thing is the stringy swarf that wraps around the work piece and eventually throws itself all over the bench. A vacuum cleaner nozzle close to the chuck will pick this up as it comes off the tool. Glen Reeser ------- Date: Tue, 20 Jan 2004 07:11:48 -0600 From: "Mario L Vitale" Subject: Re: Early Atlas 7"? [Metal_Shapers group] "cdmacmanus" wrote: > The original vise came with it and also a > pair of cast iron legs. The only damage apparent right now is a > chunk that was cut (hacked) out of one of the belt guards to allow > the installation of an Atlas motor with shafts on both ends. I sympathize with your distress over the hacked up belt guard. I don't know how large or complex a chunk was removed, but you might consider fabricating a replica of the missing piece and braze or silver solder it in place. If you dress down the braze / silver solder joint and repaint it, it will be almost like new. Good luck with your new toy. Mario ------- Date: Tue, 20 Jan 2004 07:48:03 -0600 From: "Ray Ethridge" Subject: Re: Early Atlas 7"? Or, if you really get the illness terminally you can make yourself a pattern using the old one and cast it out of home made ZA-12! It is a mix of zinc diecast scrap (which is usually 4% aluminum), aluminum and copper. The end product is 11 percent aluminum, 1 percent copper and the rest zinc. I use aluminum cans and copper wire to make mine. It is a very good alloy to cast with, relatively low temp, close to the mechanical properties of iron and machines like a dream. (Weight percent.) I do mine in my turkey fryer. There are some pics of it here: http://www.castolonllc.com/TurkeyFoundry/ Ray Ethridge ------- Date: Tue, 20 Jan 2004 12:19:56 EST From: CaptonZapx~xxaol.com Subject: Re: Atlas 7" vise ? [Metal_Shapers group] rayx~xxchlog.com writes: > Or, if you really get the illness terminally you can make yourself a > pattern using the old one and cast it out of home made ZA-12! Ahh, yes, a man after my own heart! But why not make it in ZA-27? With heat treating, it is supposed to approach the physical characteristics of cast iron. A query on the casting group board elicited the info that ZA-27 could be heat treated by heating to 610 deg F, and cooling slowly. I haven't found the cooling rate yet, but it's out there some where. Thanks for any information, CZ ------- Date: Wed, 21 Jan 2004 06:07:08 -0000 From: "kc1fp" Subject: Re: Atlas 7" vise ? ZA-12 gravity casts much better than ZA-27. JP ------- Date: Thu, 26 Feb 2004 21:56:12 -0600 From: "Ray Ethridge" Subject: Re: Re: Pootatuck shaper returned to protective custody (gloat) > Mahogany is the wood to make the patterns from. JP I will have to respectfully disagree with you there. I have made patterns from pine, poplar, MDF, aluminum, bondo and plaster and they all did their jobs well. I have seen some really good patterns made from acrylic, and it is fantastic for match plates because you can see how the pattern lines up on the other side so well. The material to use for patterns is what you have handy that is the closest to where you are going and that you can finish the easiest with the equipment you have handy. There really isn't one all round best choice, we have so many more choices than the old timers there is no point in limiting yourself because that is the way they did it back when. Ray Ethridge ------- Date: Fri, 27 Feb 2004 06:54:37 -0000 From: "dreilanderecht" Subject: Re: Pootatuck shaper returned to protective custody (gloat) There are actually several timbers that go under the general mahogany name, and some are rather open grained and therefore not ideal for patternmaking. Apart from that, mahogany is rather expensive these days, so I would save it for where its decorative properties are useful, and use something cheaper for patterns. Anything that will work easily to the shapes you want and take a good paint finish is fine. Locally the New Zealand Kauri was always prized for patternmaking as it is not prone to warping, has as close grain structure so does not require a lot of filling, and is easy to work. It is also good boat building timber. Sadly it is rather hard to get these days too. The beauty of the Fibreboard approach is that the stuff is quite cheap. I don't mean the sort of board that has big chips of material, this stuff is quite fine and will machine well with routers and so on. It also cuts well with a belt or disk sander, which is a good way to get draft where needed (using a bench machine, not a hand held one). You can fill "mistakes" with ordinary builder's filler, glue it with epoxy or PVA glues, and once it has a good coat of gloss paint on nobody needs to know what is underneath. ------- Date: Fri, 27 Feb 2004 07:22:08 -0000 From: "kc1fp" Subject: Re: Pootatuck shaper returned to protective custody (gloat) I understood there was an offer of scrap pieces of wood and of the listed woods I would chose the mahogony. I didn't mean to imply it was the best or only material to use. It is relatively stable and not soft so it will take the ramming, it sands up well and will glue together well. I did point out it is used by a commercial foundry up my way; maybe that was my mistake. JP ------- Date: Mon, 29 Mar 2004 22:34:51 +0200 From: "Frank Hasieber" Subject: RE: Re: castings/Fabrications >>>Subject: [Metal_Shapers] Re: castings/Fabrications Yes, the main reason for us to use castings at all is to maintain original appearance. Fabrication has replaced casting for most of the equivalent stuff these days. There are a few important exceptions of course, like engine blocks. regards John <<< One of the advantages of cast iron is its inherent vibration and resonance damping properties, which give a better finish to machined surfaces. Regards, Frank. ------- Date: Tue, 30 Mar 2004 00:46:18 +0200 From: "Frank Hasieber" Subject: RE: Re: castings/Fabrications > The rule of thumb for Cast Iron VS Fabricated Steel is that Cast Iron > vibrates 10 times less. Art Thanks Art, I would not consider buying a machine tool where the major components were not cast iron. Frank. ------- Date: Mon, 29 Mar 2004 23:58:25 -0000 From: volzmechatronicx~xxyahoo.com Subject: Re: castings/Fabrications Frank-- Another rule of thumb (these aren't exact--tens are easy to remember while retaining the approximate magnitude) is that synthetic granite vibrates 10 times less than cast iron. Hardinge uses their version "Harcrete" for bases of some of their machine tools: pre- machined steel parts can be inserted and fixed in special casting jigs as required. Synthetic Granite doesn't need to be stress relieved either and is a cold pour: no foundry and no welding. Philly Resins ( http://www.phillyresins.com ) states that a version of their synthetic granite vibrates 8 times less than CI and 25-30 times less than fabricated steel. However, fabbed steel can be designed with internal cavities that can be filled with other vibration absorbing materials such as oiled sand, gold bricks, etc. Lincoln Electric has a terrific book on fabricating with weldments complete with nomographs (alignment diagrams) so no computers are needed to arrive at design data. Joe W. and I experimented with a Portland Concrete lathe bed several years ago...but, we just couldn't develop anyone's interest...so it now is a "decorative" casting out back in the garden between the two Fuyu persimmon trees. It's name was "X-cretia I". Art (Houston) ------- Date: Mon, 29 Mar 2004 21:09:19 EST From: toolroomtrusteex~xxaol.com Subject: Hogging from solid versus using castings1 Dreilandereacht wrote: //General rule of thumb these days is to only use a casting where the design actually really requires it...many simpler parts can be machined from solid quite readily. For a one off, this will take a similar amount of time to making the pattern. For enabling others to make them, you save the cost of shipping one part and they can get the bar stock probably cheaper than the cost of the casting.// I'm talking newby/dilettante here since I don't have either of my shapers up and running nor the 4x6 bandsaw. I expect when I get into serious use of my shaper, I'll try to hog work out using the metal cutting bandsaw where possible. I'll also use my drill press to drill out metal where possible. To me, the shaper is used for finishing cuts where possible, rather than cutting down from solid. AIR Duplex mentioned in Model Engineer (and likely in the Shaper book too) that a hacksaw blade holder was useful for a shaper tool. Actually, I do the same with a metal lathe too, cutting out as much metal as I can with drill bits and a bandsaw. I understand that you have to leave enough metal that you can turn off a 1/16" or so of solid inbound of say chain drilled hioles to allow for finishing. I know how to grind high speed drill bits so they are selfcentering and can do chain drilling without going into the adjacent hole and breaking the bit. Larry Murray ------- Date: Tue, 30 Mar 2004 03:18:44 -0000 From: "dreilanderecht" Subject: Re: Hogging from solid versus using castings1 > I expect when I get into serious use of my shaper, I'll try to hog > work out using the metal cutting bandsaw where possible. Well, you will surely find the bandsaw very handy, since it saves a lot of time that might otherwise be used in machining parts from solid, and as well you tend to get chunks of metal that might one day be useful...:) Good for things like squaring up round pieces, like slices off that continuous cast iron bar. Machine tools should ideally be used only where absolutely necessary, using cheaper methods where possible. This can include flame or water cutting too if the facilities are available. Actually I was admiring a replica cylinder casting for a Simpson Strickland steam launch engine on Saturday...a beautiful piece of work, which includes the bottom cylinder covers and the steam chests in one casting. A minimum of actual machining is needed. Of course these days the cost balance has changed a bit so we can afford to do more machining sometimes, and don't always have access to other methods. Are you onto the technique of using hole saws? The decent HSS ones, not the cheapies from the hardware store. These can be used to make a hole, they can usually go in about 1.5 inches, so going from each end you can get a hole through a three inch thickness of metal, and you get a potentially useful round piece from inside. You can also use them the other way around, eg put it in from the end and then a parting tool from the side to take a ring off. You naturally need to put a boring tool through afterwards when you are making a hole, but it can save a lot of time. On the other point that was raised, the better damping factor of cast iron, I wonder how much difference this makes for amateur stuff really? Especially if we are generous with the sections. And if you are making a frame for a machine and think it will matter, then a composite setup with steel for sliding ways supported by concrete or epoxy grout a la Art will probably work better than the cast iron and save you the trouble of finding a cooperative foundry. It is better to have a real one that works than an ideal one that you haven't built yet. regards John -------- Date: Mon, 5 Apr 2004 12:34:11 -1000 (HST) From: benedictx~xxhawaii.rr.com Subject: Re: CNC Milling - Wax Jewellery Models [taigtools group] On Tue, 6 Apr 2004, plebe3031 wrote: > I am new to the group and work as a wax model maker/carver for the > jewellery industry, plus I also do some design using the Rhino CAD > package. I also have some knowledge of CNC machining. My questions > to the users of a CNC Milling machine are: > [a] Are there any users in the group that use a taig mill to produce > wax models fro jewellery? I'm not, but my wife is increasingly getting into jewelry making and keeps eyeballing my mill and the wax bar stock in the Rio catalog. I expect I'll be doing it before too long. > [b] If so, what has your experience been the equipment. Can't answer that one quite yet in terms of wax cutting. For cutting brass, steel, aluminum, wood, ABS, PVC, acrylic, acetal, and a bunch of other stuff it's great. > [c] Does the machine have the accuracy and repeatability to produce > small intricate pieces? Yes. I can hold 0.001" pretty easily. > [d] What CNC software are you using? Vector CAM is what I'm mostly using right now, but I'm in the process of learning CNC Toolkit running on GMAX. Vector with NURBS should be able to import Rhino models just fine. I don't have enough experience with CNC Toolkit to say how well that would work out. > [e] Can you forward digital photos of some of the pieces produced? Check in the Photo area for the mailing list. I don't know how much wax stuff is there, but I've got at least one picture of some stuff I cut in brass. It's in as-cut state, no polishing, so you can get an idea of the cut quality. These are round things, and likely aren't using the same setup you'd be using (I'm guessing you're talking about ball end mills doing contour cutting). But it'll give you some ideas. The parts are about half a millimeter in diameter and a few millimeters long with features on the order of a thousandth of an inch. (Sorry for the mixed units.) > [f] Would you buy another taig CNC mill? You betcha! I've occasionally had to pass on some ideas because they'd have tied up my mill for the forseeable future. If I had two mills I'd have pursued some of them. At the moment I can't afford a second one, though, so for me it's a moot question. Tom ------- Date: Sat, 08 Jan 2005 03:38:14 -0000 From: "ggfinger65" Subject: Turning wax on lathe I was wondering if anyone had a setup to turn wax on a lathe? I want to turn a ring from jewlers wax for my Wife, then have it cast. Wax is a little brittle to put in the 3 jaw chuck. I also dont want my knuckles that close. I thought that I might try using double stick tape on a faceplate and handheld handmade mini lathe tools to shape it. Any help welcome. Rob ------- Date: Fri, 07 Jan 2005 19:57:46 -0800 From: "Scott A. Stephens" Subject: Re: Turning wax on lathe There are harder waxes for machining. One Brand is Ferris. You can do an Internet search for them. Rio Grande also sells different grades of wax. ------- Date: Fri, 7 Jan 2005 22:18:25 -0600 From: "D Cranston" Subject: RE: Turning wax on lathe There are waxes made for machining. See Freeman Supply http://www.freemansupply.com/MachinableWax.htm Dennis Cranston Houston, Texas ------- Date: Sat, 8 Jan 2005 11:21:13 -0500 From: "Pete Brown \(YahooGroups\)" Subject: RE: Turning wax on lathe I use Freeman Machinable Wax on my mill. It will hold up to just about anything, but cuts really well. It is available in rounds as well as blocks. It definitely is not brittle. Pete ------- Date: Sat, 8 Jan 2005 11:47:19 -0500 From: "Ron Ginger" Subject: Re: [Turning wax on lathe You can buy wax in the shape for rings from jewelery supply places. All the common ring cross sections are available. You slice off a piece as wide as you want, like slicing off salami. Then carve into the ring whatever design you want -- or add-on pieces and shape them. This is of course all freehand work, not machined. ron ginger ------- Date: Sat, 8 Jan 2005 12:07:18 -0600 From: "Terry Wellman" Subject: Re: Turning wax on lathe Hi Guys, I have a prototyper who uses wax and modeling board to create prototypes with his CNC mills and lathes. He has a 5400 and 4000 lathe that are both CNC'd with Flashcut and other anciliary components. I don't know exactly which servos, etc are on his Sherline machines. He also has a Gemvision 4 axis CNC REVO mill. He cuts wax and PUR modeling board for prototypes and molds on a daily basis. I have seen a lot of the same ring stock that Ron Ginger mentioned in his shop. He uses it on the mill and lathe. He is now also using some modeling board that we created here in our shops. We have worked together on several projects where I am supplying him with Shore D 74 hardness PUR modeling board that we now manufacture in-house. We have both used this material on our mills and lathes. It cuts quite nicely and is cheap to work with, especially if it is to be used as a mold master for an RTV/Resin casting process. It's not wax but it cuts very well and doesn't melt when using a higher RPM. HTH. Terry Wellman ------- Date: Sat, 08 Jan 2005 19:55:48 -0000 From: "montanaaardvark" Subject: Re: Turning wax on lathe What a coincidence! I just machined a wax ring on the lathe and it's being carved on the CNC mill as I type. Maybe I can help. This is my second ring carved in wax. Over the holidays, I got my process going and carved a simple example. If this one works, I'm going to cast it in Sterling and wear it. To begin with, get a good jeweler's wax like the Ferris ring blanks people are talking about. I'm using Matt wax, but that was for convenience. I have Ferris, too. Ring tubes come in symmetrical (which is probably best for what I'm doing), offset and some with large flat tables on them, in a variety of hardnesses and types. They are pre- formed with a hole that is about a size 4. I cut a 1/2" long piece of wax off the tube, chucked it into the 3-jaw on the lathe, then bored it to the ring size with a boring bar. There are many charts cross-referencing ring size to diameter online - try http://www.weddingbandsuperstore.com/ringsize.html Now the problem shifts to the outside of the band and holding it. I had previously made up some mandrels that are 1" in diameter and then step down to the ring size. I slipped the band onto that, then bonded it in place with some low-temp melting wax that jewelers call "Sticky wax". Once the ring was secure on the mandrel, I put it back in the 3-jaw and turned it to the right OD for the carving to start (from about 1.09 down to .9"). Then I took the 3-jaw off the lathe, moved it to the CNC mill (rotary table), and fired up the program. I've been playing at this process for a while; it seems like it's going to work. I'll let you know in a few hours if it came out. Does that help? Bob Montana_Aardvark ------- Date: Sat, 08 Jan 2005 21:31:06 -0000 From: "Glen Reeser" Subject: Re: Turning wax on lathe I have done quite a bit of lost wax casting of items turned on my Sherline. Take a look at Glen's Projects in the [sherline group] photos section. The pens were turned out of green "file wax" from Rio Grande. I made a stepped mandrel for different ring sizes and knurled it to grip the wax rings on the inside. The knurling is enough to hold the wax without any glue. Here's a tip; use kerosine to smooth the surface of the machined wax. Brush it on with a small artist's brush. Glen Reeser ------- Date: Sat, 8 Jan 2005 20:24:42 -0800 (PST) From: gizella lathourakis Subject: Re: Re: Turning wax on lathe I have been turning & carving wax for 45 years. As I understand it Ferris manufactures for matt. My favorite is the green, I cut off about 1.5 inches to have chucking room, I bore out the size needed a bit deeper than needed, turn down the exterior as needed then I part it off. I use the stub for pieces I have to hand carve. Wax is really rather cheap. Have fun. Ron Wilson ------- Date: Thu, 13 Jan 2005 17:10:45 -0500 From: Tom Bank Subject: Re: Speaking of Machining Wax.... I haven't seen it yet in this thread, so I will add it here: When you clean up those wax chips, don't throw them out. They can be melted down and recast into blocks or any shape you want for future machining projects. Regards, Tom Bank ------- Date: Thu, 13 Jan 2005 23:28:27 -0000 From: "fionn13" Subject: Re: Speaking of Machining Wax.... You can re-melt the wax as Tom said, but when you do, I find you lower the hardness of the wax, so if you had hard jewelers wax, and you re-melted it, you would have a wax around the hardness of the medium one. Also you run the risk of having air bubbles in it unless you use a vacuum. I don't re-melt my wax, it's so cheap it's not worth the trouble. Chris ------- Date: Tue, 01 Feb 2005 21:41:39 -0000 From: "bitshird" Subject: Holding carving wax [taigtools group] I know several people that are making Jewelry master patterns using a Roland MDX 15 and they are using some type of double sided tape to secure the work piece to the table. In fact some are using Aluminum and making direct molds for wax injection, I've made several ¼ Plexiglas plates which I can clamp to my table but I'm not sure what type of double sided tape to use, and then how the heck do I get my piece off the wax. My reason for not clamping the wax to the table or to the plexi is surfacing, since the saws don't offer quite parallel cutting I need to surface the wax pieces before I machine the part, and clamps get in the way, a vise isn't much better because I usually cut the wax slices at 0.125 to 0.250 my parts are 0.070 to 0.200 this is why I'm wondering how to get the part off the tape, without breaking it. Thanks Ken Ferrell (bitshird) ------- Date: Tue, 01 Feb 2005 19:20:01 -0800 From: Don Rogers Subject: Re: Holding carving wax >what type of double sided tape to use, and then how the heck do I >get my piece off the wax? Sticky Paws. It is great for wax. It is a very thin double sided tape used on furniture to keep your cat from clawing it. It leaves no residue, and is easily removable. On the other side, it holds great. I've used it for a couple projects, including some 4mm high earing waxes with 0.5mm wall thickness. It comes in sheets of apx 1 1/2" wide strips around 11" long. The wife picks it up for the cats, and I nab a sheet now and then. Check your pet store. Don ------- Date: Wed, 2 Feb 2005 20:01:54 -0800 (PST) From: R Thomas Subject: Re: Holding carving wax I have used vacuum to hold plastic parts for machining with a 5hp 3-axis CNC router. I machined a manifold with an o-ring type gasket material layed into the manifold block just inside the perimeter of the part. There were blocks clamped around the outside of the part to keep it from rotating but these were only required for smaller parts. Depending on the density of your wax it may cause deformation on the bottom. To limit the deformation you can experiment with the amount of surface area effected by the vacuum. I usually used about half of the surface for holding and the other half for support. Look up vacuum clamp, vacuum generator, vacuum hold down, etc. The vacuum generator is the only custom part required if you don't want to buy a kit. http://woodworker.com/cgi-bin/FULLPRES.exe?PARTNUM=104-741 Richard www.homemachineshop.com ------- Date: Thu, 03 Feb 2005 12:11:06 -0000 From: "jamesbabcock2004" Subject: Re: Holding carving wax I have been cutting plexy glass for weeks. I got double sided duct tape from Lowes. If you use a piece of MDF board and clamp that to the table then use tape on top of that it will hold quite a bit. I have to work hard to get the piece I am working on off of the tape. Jim ------- Date: Thu, 03 Feb 2005 20:14:45 -0000 From: "myerm38" Subject: Re: Holding carving wax I've been cutting carving wax for some time. This may not work for you, but it does well for me: Make an aluminum tray to hold wax, one that has a good thick base that you can clamp into the vise. Then put wax pieces in it and throw it in the oven for a few minutes. The wax melts into place and holds firm. Plus I can reuse the wax several times. Marc ------- Subject: Pouring pewter rings. [Oldtools list] From: Jim Thompson Date: Thu, 14 Apr 2005 14:15:42 -0700 Today I poured some pewter rings on a piece I am turning in the lathe. I have done this before with results that were less than perfect. Today I decided I was going to get it right. I took 4 pictures showing the method and posted them at: http://homepage.mac.com/oldmillrat/PhotoAlbum74.html As Scott Grandstaff explained it a while back, it is necessary to have the metal a little higher than the finished surface so that you have something to cut. I accomplished this by putting 6 wraps of cheap masking tape on each side of the groove in the wood. Then I used 2 wraps of the good blue masking tape for the mold. I left a hole in the top of the blue tape so I could pour the liquid metal in. As you can see in the picture, I also put a pouring spout on the hole and secured it with hot glue. Just a short length of tubing. The metal always wants to sink in as it cools, and this gives a little extra metal so it doesn't become a problem. As usual after I took the tape off I could see that I had dips and dents in the metal caused by pouring the metal a little too hot. I decided that this time I was going to find out if I could fill the dips with solder. I dug out a propane torch and one of the old time heavy soldering irons that I posted about a while back because I knew a small electric soldering iron was not going to get hot enough. I heated it up and used some ordinary 50/50 solder. It worked like a champ! Good color match too. After I got the soldering done I took another cut off the metal, and it is going to be just fine! I am glad I decided to do this because I now have confidence in the process. And this is something anybody can do! No high degree of skill required. Jim Thompson, the old millrat in Riverside, CA. ------- Subject: Fw: Pouring pewter rings. From: "Charlie Driggs" Date: Thu, 14 Apr 2005 19:16:48 -0400 Frank asks ... Why did the tape not melt/burn when you poured in the very hot metal? Well, Jim commented that he poured with the pewter too hot, but the actual pour temperature isn't all that high -- not high enough to light off masking tape anyway. Scott and Jim provided enough explanation that I tried it a couple years ago and found it produces a great effect (if you don't try anything too complicated) without much difficulty. Charlie Driggs Newark DE ------- Subject: Re: Pouring pewter rings. From: "Todd Hughes" Date: Thu, 14 Apr 2005 19:37:16 -0400 I have poured many hundreds of pewter rings and ferrules while making knives, is a very authentic knife construction method as well as other tools of course.I would just cut a strip of brown paper, [old shopping bag] and use it like Jim did his tape. If casting a ring where you need two raised shoulders so that the pewter would stand proud I would just use the paper wrapped around and held together with scotch tape. The paper you pour the pewter though I held in place with a piece of string after having the scotch tape I used once come apart from the heat. Little exciting but not in a good way....Speaking of excitement always make sure that there is no moisture or water where you are pouring the pewter as it will turn to steam and blow the pewter all over the place....again I know!. I read someplace that if you coat the place you want the pewter to go with graphite it will run better. Don't know but I always did it and maybe it worked better. You can pour inlays just make sure you undercut the wood to hold it in place. Once I made a knife that had many rings and inlays and I just put the handle in a heavy paper tube and poured the pewter all around it and then filed it clear. Remember is easier to remove to much pewter then not having enough. As Jim found out you can patch weak spots....sometimes Before I figured it out that I could use old solder and Tin that I found at the flea market for pewter I used to buy a good bit of old junk pewter to melt down. I collect antique pewter so don't worry never melted anything good OK? Once I was at an auction and got some pieces cheap including a big platter. Setting there I took the platter and folded it in half and stepped on it to make it flat to fit in my bag. Woman setting next to me looked shocked and asked me what in heaven was I doing! I told her I always fold up my pewter like this and when I get home I just unfold them....She got up and moved to another seat. Todd ------- Date: Tue, 6 Sep 2005 19:18:39 -0400 (GMT-04:00) From: Jim Ash Subject: Re: Casting [atlas_craftsman] On Sep 6, 2005 Jo Barden wrote: >>I don't know if anyone has mentioned it but http://www.backyardmetalcasting.com/index.html is a very good website and the flower pot furnace works well. Jo << I'm in the Gingery machines yahoo group, which is based on casting your own parts and making your oen machine tools. I built the charcoal foundry (Gingery book #1) and melted a bunch of cans into ingots. I've probably got a hundred pounds in can-based ingots at this point. As some have pointed out, cans are almost pure 1100 aluminum. They are also lined with plastic to keep the beverage from interacting with the can. So when you melt them, The paint on the outside and the plastic on the inside (and whatever decided to crawl in there and make a home) burn off. There is a lot of dross, but it can be skimmed off. The dross helps a little in keeping the combustion gases away from the metal while it's being heated. It's an amusing exercise, and if you don't really care about the material properties of your aluminum, then go for it. If you're going to cast things that have to be structurally useful, you might consider other sources. Old pistons seem to be a preference for many. I was thinking about old lawnmover powerheads from the town scrap pile. Try to stay away from aluminum alloyed with magnesium. Some of the guys put in chunks of zinc or copper to adjust their own alloy contents. Please, please; two words of warning. Some of the stuff I've seen websurfing is fearsome. First, get good personal protection. This means good heavy leather footwear, like work boots. No sneakers, hiking boots or anything made with cotton or plastic uppers. The amount of heat energy stored in molten aluminum is amazing. It won't even slow down at cotton or plastic before going for your feet if you spill it. Heat resistant gloves (I use welding gloves) and a face shield are also necessary. Second, find a safe place to operate your foundry and do your pour. A bed of sand is ideal, but I used to do it on a patch of level dirt next to the house. Absolutely NOT over concrete. If molten metal gets spilled on something with water in it, the something could vaporize fairly quickly and things start flying everywhere. There's enough water in regular concrete that it will spall and send molten aluminum and concrete all over the place. This said, have fun and go for it. It personally opened up a world for me that I couldn't have had by making things from bar stock and machining it down. Difficult machining exercises can be reduced to simple castings sometimes. Jim Ash ------- Date: Tue, 06 Sep 2005 19:30:17 -0400 From: "mertbaker" Subject: Re: Casting We had an Al foundry in my shop classes when I taught metal shop. There were 14 in the class, 4 were pouring, and the rest were on safety details armed with CO2 extinguishers & shovelfulls of molding sand waiting for catastrophes. There were none, in the 3 years I had the class, as they had all been trained before they actually poured. They took turns at each job on different pours. And they ALL wore heavy shoes, canvas leggings with leather spats, elbow length gloves, hats, and face shields. (So did I. -Have to set examples; the kids watch the teacher.) Mert ------- Date: Tue, 1 Nov 2005 20:58:51 -0800 (PST) From: juan gelt Subject: Re: milling metal molds for jewelry specific designs [taigtools] wrote: > I recently have been investigating using the mill to mill designs > into metal or a composite material for plastic injection. > Does anyone have any suggestions in resources for learning more > about this process? Any suggestions, greatly appreciated. Americo for mills, taig! nick carter's site: http://www.cartertools.com/ for broad ranging topics of the cnc and manufacturing variety: cnczone.com forums for general info on molding of all sorts: www.hobbymolding.com forums for a small plastic injection molder: www.iasco-tesco.com for a specific example of an injection mold made on a desktop mill for a desktop injection molder: http://cnc-g-spot.com/testmold/TestMold.htm If you plan on injecting wax or doing low pressure molding, you might consider silicone molds and bypass the whole cnc issue. ------- Date: Wed, 2 Nov 2005 08:49:53 -0800 From: "Larry Richter" Subject: Re: milling metal molds for jewelry specific designs The main trade association for plastic injection molding, the name of which I have forgotten for the moment, released books and software that changed the mold design field permanently about twenty years ago. By now there are probably commercial examples of similar design helps available for specific areas of injection molding from other sources. If you are specifically interested in molding pieces for jewelry, you could probably start by talking to the right product advisor at Rio Grande: 1-800-396-9896 or 505-839-3247 www.riogrande.com Almost anything that is sold commercially to make jewelry parts they will sell a version of, and most developments in the field they will either be familiar with (that's most of most things), or they will at least know of. For what they sell, their information will be current. Many of the product advisors were manufacturers themselves. Their interest in jewelry making is usually genuine and personal. It's fairly low pressure. They seem to think that if your interest is serious, that their merchandise is good enough that eventually, if you manufacture, you'll want some or need some. They have a good catalog. Also, they have a Living Catalog they put on at one of the big gem and mineral shows, where they display their goods in the hands of experts, conduct 8 days of free seminars in beginning and intermediate jewelry techniques, and also hold hands-on classes, some at expert level, for a fee which is usually substantial but which includes materials and tools and gives you ownership of what is made. About a third of the hands-on classes are about Precious Metal Clay this year, which as I understand it can be molded. PMC makes gold and silver objects (and maybe platinum ones, too, by now. Who knows?) without traditional casting. There is a similar industrial process that makes load-bearing mechanical parts: I don't know which is developed from the other, or if they are unrelated except for similar method. The industrial process is precision, the PMC usually at least partly hand work. ------- Date: Wed, 2 Nov 2005 08:27:27 -1000 (HST) From: benedict-listx~xxhawaii.rr.com Subject: Re: milling metal molds for jewelry specific designs I saw your post on the homeinjectionmolding list, but hesitated to reply because I didn't know what kind of mill you have. Now I know! Which process are you curious about? Injection molding in metal molds, or using the mill to make metal molds? For using the mill to make metal molds, this is a pretty good list to ask questions on. Mold making uses many of the same processes that any other machined part uses, so any transition problems you might have going from machinable wax to metal should be able to be answered here. For mold making, I don't know how many people here make molds. Since you've already been doing a fair amount in machinable wax, chances are you've already run into a lot of the gotchas like providing good draft angles and good surface finish. I'll be curious to see how your molds turn out. Mind posting pictures when you get to that point? Tom ------- Date: Wed, 2 Nov 2005 12:51:32 -0800 (PST) From: americo pacheco Subject: Re: milling metal molds for jewelry specific designs I will be attempting to mill designs into a composite material called alumilike for plastic injection. I have been poking around and someone told me that the spindle speed on the Taig is not sufficient. Now I am thinking that I will need to purchase a spindle? Can anyone lend any credence to that statement? ------- Date: Wed, 2 Nov 2005 13:21:11 -0800 (PST) From: juan gelt Subject: Re: milling metal molds for jewelry specific designs. (spindle speed is adequate) Even with fairly small cutters, spindle speed is far more than adequate and you can use much bigger cutters. Everything about the Taig is adequate (I understate with a satisfied smirk). I've done ivory with features of .001 inches. For plastic injection I've used both epoxy al and epoxy steel, with fiberglass reinforcement and they will do for low res, small, roundy parts that work with lower pressures, but not ideal for high pressure molds as it will deform and can be broken. (The sq in part of the psi adds up inside a mold.) Pushing plastic thru a wide square-inchy gap to make a thin wall takes pressure. Thin walled parts do argue for a rigid mold. Might better plan on aluminum molds. That might leave some surface finishing work on the parts after -- depends. ------- Date: Wed, 02 Nov 2005 17:35:03 -0500 From: "Jeff Demand" Subject: Re: milling metal molds for jewelry specific designs Hi americo: I've been milling alumilite for about a year. Rough cuts with a 1.6 mm ball mill and finishing with a vee tool with a tip diameter of about .15mm, spindle speeds around 5000 rpm. My only problems are chip ejection with the spade type finishing tool but that is to be expected. Manual Taigs have around a 5000 rpm spindle, my (new) cnc model can push 10,000 rpm but I still use the lower speed I'm used to from my older mill. Taig mills are quite impressive little machines, overkill for alumilite. Jeff Demand Designs Analog/Digital Modelling & Goldsmithing http://www.gmavt.net/~jdemand ------- Date: Thu, 03 Nov 2005 02:43:10 -0000 From: "bitshird" Subject: Re: milling metal molds for jewelry specific designs Hi Amerigo, I have made over 1000 vulcanized natural rubber and silicon rubber molds, and I've also started doing Aluminum molds for wax injection. You are on the right track, flat shapes with very fine detail yield far crisper details than any type vulcanized or RTV mold can; that's why class rings are done in metal molds. >someone told me that the spindle speed on the taig is not sufficient I've been using my Taig 2019cr which has been CNCd with end mills from .005 up to .060 in both ball and endmills. (Try not to use any .005 as they break when you breathe on them.) I keep my spindle between 7000 and 10,000 rpm. For me .010 .015 and .025 are the main ones I've used. I keep my cuts with the .005 .002 DOC at 2.5 IPM with the bigger mills faster speeds and slightly deeper cuts. I still have trouble reconciling chipload on mills that small. At 15 to 18 dollars each you learn pretty fast; before long the lessons get pricey. ------- Re: How to build a Small home foundry [Min_Int_Comb_Eng] Posted by: "Frank Hasieber" fhasieberx~xxyahoo.co.uk Date: Mon Jun 26, 2006 12:11 am (PDT) hhelmenx~xxaol.com wrote: > Dale: Go to Lindsay publications web site. They have several good books that I can recommend for building and using your own metal melting furnace. Mike Chastain's Metal Casting Book 1 and Book 2 are very good. Also Dave Gingery's "li'l Bertha" and others are good also. I have them and I use them and they work~! Hank < There are a number of sites on casting, one of the best books you can get is the one by Michael Porter, "Gas Burners for Forges, Furnaces and Kilns". He gives very clear step by step details on making the burners (which are state of the art), and several types of kilns, all the work can be carried out using the normal hand tools a handyman would have, its available from Amazon, ISBN 1879535-20-3, you won't get better advice and details on construction $19.95, you can get it at this link: http://www.amazon.com/gp/product/1879535203/sr=8-1/qid=11513057 55/ref=sr_1_1/103-8905118-4731848?ie=UTF8 Frank ------- Casting question [Min_Int_Comb_Eng] Posted by: "Mark" sitdownbikex~xxyahoo.com Date: Mon Jan 15, 2007 9:57 am ((PST)) I posted this question on the Hobbicast Yahoo Club but it occured to me that MICE builders might have more specific knowledge of the topic... I have been casting aluminum for many years in green sand molds. Some things I cast are cored, 1.5 inch diameter and about 3 inches long. I always use green sand for these cores also, ram them up in a plumbing tail pipe, vent and then push the core out with the rammer. Very rarely have I cast with cores otherwise. I have recently tried casting something much different, it is shaped like a handle. The core is very delicate. Three areas of the core are only 1/4 inch in diameter. What I have tried that did not work very well: 1) A baked sand made from a blend of molasses, bentonite, silica sand and olivine. When I increase the binders to the point that the core is barely durable enough, it is almost impossible to remove the core from the casting. It is like trying to chip out concrete. 2) A baked sand made from a blend of molasses, wall paper paste, and silica sand. I used Steve Chastain's formula. This was so fragile it crumbled when I picked it up after baking. 3) A gypsum product for patching wall board. This worked extremely well in most respects, it is durable, easy to make and extremely easy to remove from the finished casting. Unfortunately, even though I baked the core for 2 hours at 400 F it still gassed when the molten aluminum hit it. Any suggestions? Thanks, Mark ------- Re: Casting question Posted by: "Rob" Dragondarkx~xxSprintmail.com Date: Mon Jan 15, 2007 10:42 am ((PST)) Try casting material made for jewelers. I've cast some fairly large pieces in that, and to ease removal, quench it with cold water while it's still warm. The casting will fracture in large pieces. Rob ------- Re: Casting question Posted by: "Jerry Kimberlin" kimberlnx~xxcomcast.net ate: Mon Jan 15, 2007 11:12 am ((PST)) As far as I know, there is nothing wrong with cores made of green sand. However, you need to mix in some sodium silicate. Then you can spray or gas it with carbon dioxide to make the core hard. They will air harden too but it will take a lot longer. Cores made with sodium silicate are not too fragile but can be broken out easily. I'm surprised that you didn't get this sort of answer on hobbicast, but it is more about rubber than about aluminum casting. There are other casting forums that might be better for you. JerryK ------- Re: Casting question Posted by: "Philip Burman" philip.burmanx~xxlyse.net Date: Mon Jan 15, 2007 3:16 pm ((PST)) 400 degrees F is not nearly high enough for gypsum. You have to drive off the bonded water as well as the free water, otherwise the molten aluminium will. I don't remember the recommended temperature but I fire mine up around the 550 deg C mark. They get a bit more crumbly but still work fine if you add some sharp sand, around 50/50. Regards Phil ------- Re: Casting question Posted by: "moltenmet34" jrisserx~xxmaf.org Date: Mon Jan 15, 2007 6:17 pm ((PST)) Are you familiar with the sodium silicate (water glass)/co2 process? I have used it with good results in casting aluminum. It may be worth consideration. Jason ------- Re: Casting question Posted by: "hhelmenx~xxaol.com" Date: Mon Jan 15, 2007 8:45 pm ((PST)) Mark: I have had success using plain old plaster of paris as a core. It must be "cooked" for a couple of hours before use, as you know. Also I have made small cores with the sand/flour/molassas, and water mix. With plaster or sand it might help to put a vent hole through the core with a small piece of tubing to help it vent out. "core the core" so to speak. Also when you make a small core you can reinforce it by putting a piece of stiff wire inside it if you are using the sand and molassas mix. When I have one of the small delicate ones I usually roll it out of the core box directly onto a flat aluminum plate in order to avoid distorting it with my fingers, alternatively you may be able to warm it up a bit inside the core box, if it is made of a durable and heat resistant material. This will dry it out and make it easier to handle. Hank ------- Re: Casting question Posted by: "nickjones111" nickjones111x~xxyahoo.co.uk Date: Tue Jan 16, 2007 3:18 am ((PST)) Mix 2.8% sodium Silicate bonding solution with silica sand. The ratios being mixed by weight not volume. CO2 gas is then applied at 3 - 5 psi for about 30 seconds. The advantage is you are then removing a strong core from the core box. Silica sand is available in different grit sizes typically 60 - 100 grit. In the UK 60 grit is most common but quite coarse for our purposes. You can improve the surface finish by brushing on some ceramic wash coating onto the core and baking it dry. (The wash you coat your plunger and skimmer with.) The core must collapse easily as the casting cools and contracts around it. Good luck ! Nick Jones ------- Re: Casting question Posted by: "Mark" sitdownbikex~xxyahoo.com Date: Thu Jan 18, 2007 2:31 pm ((PST)) Thanks for the suggestions, everyone. I used Crystoballite gypsum that I bought at a jeweler's supply and it worked great. Regards, Mark ------- Re: Casting question Posted by: "jamesengine2006" jsmj93x~xxsbcglobal.net Date: Thu Jan 18, 2007 5:48 pm ((PST)) Mark, I'm trying the same thing for an engine casting. Trying to use a very small diameter core - about 1/2" diameter and 5" long. One of the other groups mentioned Hydroperm so I bought some. The company says it is specifically for aluminum casting. Of the two castings that I have made so far they both had steam coming off the mold after I poured. I contacted the company and they said that the cores and molds should be dried at 400 to 500 degrees. The time will vary depending on how big the core or mold is. I'm shooting for 2 hours at 400 to see what happens next. It's also easy to remove. The first one I poured I just placed the finished casting in water and the Hydroperm core turned to basically mush. I brushed it out with an acid brush. Here is a link to their web site: http://www.gypsumsolutions.com/brand.asp?brand=HYDROPERM I ordered 100# from Laguna Clay and it cost about $60 with shipping to Northern California. Check on the gypsomsolutions web site - they may have a distributor closer. Hope this helps. JE ------- Re: Casting question Posted by: "jamesengine2006" jsmj93x~xxsbcglobal.net Date: Wed Jan 24, 2007 10:11 pm ((PST)) Mark: An update on the Hydroperm. I'm still trying - so to speak. One casting that I used Hydroperm for the core cracked so at this point I wouldn't recommend it. How is the dental stuff working? I have now decided just to abandon the core for now. I've baked that stuff for hours on end and still have some steam. I'm not giving up though - it's supposed to work for aluminum castings so obviously I don't have the process right yet :-) However the stuff makes a great furnace liner - assuming your only going to do a few melts. The stuff cracks bad when used as a liner. It isn't intended to be used as a furnace liner but I've never built a furnace that works so well - 1/2 cup of molten aluminum in 10 minutes using a 110v heating element. You can't beat that. Jerry J. ------- Re: Casting question Posted by: "Don Rogers" Donx~xxCampbell-Gemstones.com Date: Fri Jan 19, 2007 8:53 pm ((PST)) >I contacted the company and they said that the cores and >molds should be dried at 400 to 500 degrees. The time will vary >depending on how big the core or mold is. I'm shooting for 2 hours >at 400 to see what happens next When drying or burning out the wax pattern in a investment mold, it is important to get it to 300F very slowly to prevent damage to the mold. If you heat it to fast, the steam generated will blow out some of the detail and the material blown out will contaminate your metal when it is poured. I haven't been following this thread, so I may be repeating something covered earlier but here it is anyway. Ramping up your mold would go something like this. 100F for 1/2 hour, 200F for 1/2 hour, 300F for 1 hour; then you can rapid ramp from there. The moisture will be dried off just after the 200F cycle. The 300F cycle makes sure the heat has penetrated to the core of the mold. If you are using wax patterns, you need to get up to 1325F to burn out the wax. At that temperature, all carbon is reduced to carbon dioxide and there will be no ash in the mold. If you don't reach that temperature, there will be some crud left in the surface of the mold that will show and may damage your metal. You need to hold the mold at 1325F for at least 1 hour, then you can ramp down to 500F in 3 or 4 steps. Make sure each step is at least 15 to 30 minutes long. You don't want it to cool to quickly as it may crack in the process. Depending on the size of the finished product and the detail on it, you will vary the mold temperature at the time of the pour, a higher temp for smaller, finer detail and a cooler mold for larger and less fine detail. Never let the mold get below 300F before pouring, and I would suggest not lower than 500. This info is based on pouring of gold and silver as well as brass and bronze. I have no experience with aluminum, but the mold temps given allow the molten metal to flow and not freeze up prior to filling the cavity. This is basic for any metal pouring. If the metal stays molten too long, it will crystallize and give a weak finished product. If it cools too quickly, it may leave voids in the finished product. Don ------- Re: Casting question Posted by: "pacnwfoto" photecx~xxcnw.com Date: Wed Jan 24, 2007 1:23 am ((PST)) > When drying or burning out the wax pattern > in a investment mold, it is important to get > it to 300F very slowly to prevent damage to the mold. Having made investment castings for 25 years in a dental lab, I'll add my 2-cents. How fast you raise the burnout temp depends upon the size of the mold. A fist-sized investment mold can be placed directly in a 300* oven after letting the investment set for one hour. You can start with a cold oven, too, of course. We used stepped ovens that would raise the temp in selected increments: 20 minutes to 300, 20 minutes to 600, then up to 1200* and a heat soak for 45~60 minutes. There are new investments now on the market that will allow a cold mold to be placed directly into a 1200* oven without explosion. > If you are using wax patterns, you need to get > up to 1325F to burn out the wax. Wax will burn out cleanly at 1000*, but the mold needs to heat soak long enough to get the core to 1000 and remain there for an hour. > You need to hold the mold at 1325F for at least 1 > hour, then you can ramp down to 500F in 3 or 4 steps, Just open the oven door and let it cool. A hot and dry mold will not usually fracture during quick cooling. > ...you will vary the mold temperature at the time of the > pour, A higher temp for smaller, finer detail and a > cooler mold for larger and less fine detail. Mold temp is dependent upon the metal being cast. The mix and quality of the investment, and quality of the wax pattern determines the surface detail of the finished part. You can dink around with the water/powder ratio of investments to vary the mold expansion and therefore the size of the casting--critical for dental apps, but not for parts to be machined. > Never let the mold get below 300F before pouring, > and I would suggest not lower than 500. Mold temp at casting depends on the metal being thrown. Steels can be thrown into a 1500~1800* mold, and noble metals at 1000~1200*. I have excellent results throwing aluminum into a 700* mold. Investment temps below 700 will chill aluminum too quickly and cause surface wrinkles or voids in the detail, even with a forced pour from a centrifugal casting machine. Heavier metals can be cast into cooler molds if the molds have good vents. > If the metal stays molten to long, it will crystallize and give a > weak finished product. Metal will not stay hot too long after casting and cannot be damaged by a slow cool. A slow cool will anneal, a quick cool will harden-- except for noble metals which respond exactly the opposite. What does alter the crystalline structure of metal is over heating or over cooking during the melt process which can burn off some of the elements of the alloy. You can reduce the time required to melt metal with fluxes. ------- Re: Casting question Posted by: "Mark" sitdownbikex~xxyahoo.com Date: Fri Jan 26, 2007 7:56 pm ((PST)) "jamesengine2006" wrote: > An update on the Hydroperm. I'm still trying - so to speak. One > casting that I used Hydroperm for the core cracked so at this point > I wouldn't recommend it. How is the dental stuff working? Jerry, I have had good results with the crystallabolite gypsum as a core material. Reading thru the whole thread, keeping in mind that I am pouring aluminum, the casting is a decorator item (just needs to look good) and the most massive part of my core is .5 X 2.5 X 3 (a core print) but most of it is far more delicate, I have these comments: 1) I do not have a programmable oven. One hour after pouring the core I throw it in at 300 degrees. It quits steaming at about 35 minutes. After an hour I turn the oven up to 400 and leave it until ready to pour. 2) I always used a wire thru the center of the core (made from a salvaged bicycle spoke) to make the core more durable. When using the wall board gypsum, the wire expanded at a faster rate than the gypsum which would crack the core. No such problem with the crystalabolite gypsum. 3) The 400 degree core is quite delicate. I dropped one and it shattered into tiny pieces. I never broke one putting it into the mold tho. 4) I take the hot core out of the oven, put it into the mold, close the mold and pour all in less than a minute. 4) I am making the mold from green sand and the core from gypsum. This makes the green sand mold act like a chill. The interior has ribs that show what would be unacceptable shrink (remember the casting is a decorator item) due to hot spots. If I was making something like a crankcase or cylinder I would try letting the core cool off overnight in the oven and pour the next day. 5) The core is extremely easy to remove. I just poke at it with a screwdriver and a wire. The core breaks up and falls right out. 6) The gypsum cost $14 for 2 Kg which is enough to make 18 of the cores. Furthermore, I too use an electric furnace. Mine is based on the Lil Bertha. It has no controls because I only want it to melt faster, not slower. I used furnace cement/vermiculite mixture for the refractory and a 18 ga, 8 ohm nichrome wire heating element. My furnace melts 6 pounds of aluminum from a cold start in about 2.5 hours. Regards, Mark ------- Re: Casting question Posted by: "jamesengine2006" jsmj93x~xxsbcglobal.net Date: Fri Jan 26, 2007 9:49 pm ((PST)) Mark, Good info - thanks! I built a furnace using the same stuff. At the time I didn't have anything to cast so it got thrown out in one of the moves. I also built one using the fire brick with notches in it but again - didn't have anything to cast. Now I have something to cast and can't get it to work :-) When you mix the gypsum do you mix in air at all? I've changed my miking procedure to induce more air per the instructions RTFM :-) So maybe things will get better. When I used the core it looked like the casting cracked around the core when it cooled. Does any of your castings have cracks from shrinking around the core? Thanks Jerry J. ------- Re: Casting question Posted by: "Mark" sitdownbikex~xxyahoo.com Date: Mon Jan 29, 2007 9:18 am ((PST)) Jerry, I hope you do not mean that your furnace does not work... I do introduce air into the plaster while mixing. I put the ingredients into a tupperware tub and shake. However, I do not think that this contributes to the crushability of the core. I mix the plaster with 2-5 percent extra water so that it will be weaker when cured and therefore easier to remove from the casting. Since the plaster is thin, the bubbles rise to the top when pouring. Air should not be needed. According to the instructions that came with the plaster, it should be mixed and then put in a vacuum chamber to remove the bubbles before pouring into a mold. I personally skip the vacuuming. If you want bubbles in the plaster, CW Ammen recommends a little dishwashing detergent in the water. After mixing the plaster, water, and detergent, whip it with a paddle mixer like for drywall mud (he was obviously doing LARGE cores). I believe that my technique prevents a problem with the core causing the cracking that you describe. Since I put the hot core into the mold, close and immediately pour, the core is still much hotter than the greensand mold wall when poured. This means that the outside of the casting cools first. The wall of the casting shrinks away from the core. Also, the core being hot means that the core has expanded somewhat as well. After the metal is poured, the core shrinks right along with the metal. HTH Mark ------- Re: Casting question Posted by: "jamesengine2006" jsmj93x~xxsbcglobal.net Date: Mon Jan 29, 2007 5:27 pm ((PST)) Mark: The furnace works great - it's the gypsum molds I'm having trouble with. I'm going to switch the way I make the molds and try again. I've been mixing air into the Hydroperm per instructions and it seems to work better for the mold - however - I don't think it would work for a thin core. I believe it has something in it to act like the a detergent to trap air. I haven't had any problems with steam since I started mixing in air. On one pour, I left the aluminum in the furnace a couple of extra minutes and it was so hot I couldn't see any aluminum color. The whole thing looked like lava - about an orange color. It poured like water also. Of course it promptly went straight out between the mold halves and ruined the casting :-) Jerry ------- Re: Casting question Posted by: "Mark" sitdownbikex~xxyahoo.com Date: Tue Jan 30, 2007 10:00 am ((PST)) Jerry: That would definitely be too hot. It is not just that your casting was ruined by runout at the parting plane, that does not always happen when you pour too hot. Pardon me if you already know this, but some of the lurkers might not. Even if the casting was intact, you probably would have had hydrogen porosity. Molten aluminum steals hydrogen from the moisture in the air. Solubility of hydrogen in aluminum increases dramatically as temperature increases so a few degrees can make a big difference. The hydrogen dissolves into the melt. As the metal freezes, the hydrogen comes out of solution and forms bubbles. It may not spoil a crankcase casting but would definitely spoil a cylinder or piston casting. You should always pour the metal as soon as it reaches the lowest temperature that will give good results in the mold. For this reason my most common misrun is caused by pouring too cold. Steve Chastain's 2 volume book, Metal Casting: A Sand Casting Manual for the Small Foundry goes into this topic in detail. It looks expensive for a couple of little paperbacks but it's the best money I ever spent (and I have not spent much...) on my foundry. For instance, he explains how to make a dirt cheap thermocouple pyrometer (next on my list of foundry tools to acquire) so misruns due to too hot or too cold pouring can be a thing of the past. HTH Mark ------- Re: Casting question Posted by: "Mark" sitdownbikex~xxyahoo.com Date: Wed Jan 31, 2007 9:36 am ((PST)) "jamesengine2006" wrote: > Mark, The cope and drag where cast Hydroperm in a silicon mold. The > parting surface wasn't perfect which caused the run out. My next try > I will cast the cope against the drag to get a better seal. I had no > chance to check for hydrogen porosity - it ALL ran out :-) > I did have one casting with hydrogen porosity - so I'm guessing :-) > It was when I used pre cast aluminum from a valve cover. All the > other pours have been using extruded aluminum. It seems to work > better - don't ask me why. I've heard that you want to stay with > pre cast aluminum because the properties are different. Have you tried > the extruded at all? Any good results with it? Jerry: Thanks for the clarification about the parting plane defect. Sounds like you are getting it sorted out. We need to define some terms to continue the conversation. Extruded stock: Things like angles, channels, architectural shapes and so forth. For the most part these are available retail at the home improvement store. It is unusual to find the alloy on this stock. Bar stock: This is a specific alloy sold as a bar for machining or fabricating. The alloy is printed on the bar every foot or so. While it may be extruded, it is a different class of product from the above. Now, I have not had much luck casting extruded stock by itself. The problem is that it melts at a very high temperature. It also has a broad "soft zone" between the solid and liquid phase. Materials that are extruded need the soft zone to facilitate the extrusion process. This makes them worse for casting because such an alloy is prone to shrink defects, does not flow readily and needs to be overheated to flow at all. Bar stock may be OK for casting. It depends on the alloy. I have had mixed results with 6061 and somewhat better results with 2024. My favorite scrap is mic-6 cast tooling plate. Since it is a cast product, it works great. I have no idea how to heat treat it tho. Casting alloys often have a comparitively (as opposed to extrusions) abrupt transition from the solid to liquid phase. For castings that need good mechanical properties, buy an ingot of known alloy and do not add scrap. Buy something that you can heat treat if you need to. I buy most of my casting stock as offcuts from a warehouse. I pick through what they have looking for pieces of mic-6 that will drop into my crucible. For what I am doing the price and convenience can not be beat. Most jobs I do are either lightly loaded (Gingery machines, vacuum forming patterns, etc.) or decorator items. For these I like to use at least half (preferably 3 fourths) mic-6 and the rest bars and extrusions depending on what I have laying around. If the item to be cast is massive, like an angle plate, then I melt a whole crucible full of extrusions. I would say you are probably overheating as a general practice due to the fact that you are accustomed to judging heat by melting extrusions. Also you said that when you melted a valve cover casting, you got a porous casting. Try using just aluminum from scrap castings and pour as cold as possible. My crucible is a dull red, just barely glowing in a dark garage when I pour. Degassers should not be required if you use good melting and pouring practices (pouring as soon as the metal is hot enough, pouring at the lowest temperature that still gives a good casting). I have religiously avoided degassers because the fumes they release are toxic and I too melt in my garage. It is probably just as well to make critical parts of an engine out of bar stock as opposed to castings. With bar stock you can buy exactly the properties that you want. However, there is no reason that things like valve covers and other cosmetic and non structural parts can not be cast out of scrap aluminum. HTH Mark ------- Re: Casting question Posted by: "jamesengine2006" jsmj93x~xxsbcglobal.net Date: Tue Jan 30, 2007 3:51 pm ((PST)) "Ron Coath" wrote: > Teve can you recomend a book supplier for to 2 books. > Ron. Canberra Australia. Ron: One Horse Outfit on Ebay has a lot of great books. I have bought from them before and they are reliable and prompt. Here is their link: http://stores.ebay.com/ohojims-One-Horse-Outfit Do a search on "casting". There are two volumes to the set. Jerry ------- Re: Casting question Posted by: "Mark" sitdownbikex~xxyahoo.com Date: Wed Jan 31, 2007 9:37 am ((PST)) Also check out: http://www.lindsaybks.com/prod/sub/foundry.html Regards, Mark ------- Re: Casting question Posted by: "Roger Patterson" rlpattersx~xxshaw.ca Date: Wed Jan 31, 2007 10:59 am ((PST)) They are also listed at www.ploughbooksales.com.au Roger ------- One off castings [Min_Int_Comb_Eng aka MICE] Posted by: "BillB" wabit2x~xxgmail.com Date: Thu Dec 13, 2007 6:49 pm ((PST)) Hi, The comment about what a "casting can offer" are near and dear. Several things ( MICE related ) I would like to do really need several castings. This is a hobby so the fancy stuff is out like buying into "Rapid Prototyping". Among these are stereolithography (SLA for stereolithography apparatus), selective laser sintering (SLS), fused deposition modeling (FDM), laminated object manufacturing (LOM), inkjet-based systems and three dimensional printing (3DP). All BIG $$$ for a hobbiest. As an alternative I have been mentally toying with a stacked wax sheet process. The idea is simple: Wax sheets of various thickness cut out to the cross section of that region of the item of interest. These sheets would then be bonded together. Hand carved to smooth surfaces and 3D features. Then the next layer. Finally dip the wax in an investment coating (or coatings ). Then do a lost wax casting. I live in town and have both city and HOA rules to deal with so I would be limited to zinc alloy or aluminum but in reality either should work. QUESTIONS : Have others done this ? Where do they hang out ? Does it sound reasonable ? What major problems do you see ? Regards BillB ------- Re: One off castings Posted by: "James A. Lee" scriviamox~xxgmail.com Date: Thu Dec 13, 2007 8:08 pm ((PST)) BillB; As a retired "old-timer" dentist, I have made thousands of one-off castings in gold; inlays, veneers and full crowns, using Cristobalite as the investment medium. What you would do in castings for engines is exactly the same, except for the size. Really, the only problem of any consequence is the expense of the larger apparatus (burn-out oven, melting furnace and casting machine, pressure, vacuum or centrifugal) required. A very nice feature of the lost-wax process is the extremely fine and accurate surface detail routinely achievable.....all you need do is polish to whatever degree you want. I have seen some very nice designs for home-made vacuum casting arrangements that look to be cheaply and easily made, however. And a burn-out oven of medium size is really not all that expensive if one is going to do much work, and as you no doubt know, can consist of essentially a pile of firebrick and a heat source, gas or electric. The process you mentioned is getting on toward shell moulding, which can get very pricy indeed. Gypsum investment (Crystobalite is as good as any) is (or was) quite cheap by the sack. You mentioned zinc castings (Zamak). I've read that this metal is very good for our work...low-melting with quite high tensile strength. But I think that the greatest advantage offered, besides the creative possibilties, is the very fine cast surface thus freedom from out-of-scale surface roughness. ------- Re: One off castings Posted by: "jamesengine2006" jerryx~xxjamesengine.com Date: Fri Dec 14, 2007 5:43 am ((PST)) Has anyone tried lost foam casting? Here is a link that shows the general method. http://www.theworkshop.ca/casting/foamcasting/foamcasting.htm http://www.buildyouridea.com/foundry/lost_foam_howto/lost_foam_howto.html You basically make the part in foam - think blue or pink foam paneling from Home Depot. You then dip the part in an investment - the second link recommends drywall texture that works well. Place the part in sand and then pour the aluminum. The first link above does not show the foam being dipped - just simply placed in sand. Dipping it gives a better finish according to the second link. Jerry J. ------ Re: One off castings Posted by: "Frank Hasieber" fhasieberx~xxyahoo.co.uk Date: Fri Dec 14, 2007 6:40 am ((PST)) I have not tried it, I was building a furnace but it had to be put on the back burner, lost foam would be my preferred method, I found a reference somewhere that General motors cast something like 80% of all their engine blocks in lost foam, have a look at this http://web.umr.edu/~foundry/first.htm I did find another one with a lot more information on the way GM does it, but can't seem to find it! there is a great deal of info for the home foundry on the web. Frank ------- Re: One off castings Posted by: "hhelmenx~xxaol.com" Date: Fri Dec 14, 2007 8:47 am ((PST)) BillB:?? I have been working with STL parts and simple sand casting as a hobby for about 10 years now.? Investment casting is called that not because of the material used as destructive mold, but because of the cost of all the other equipment required to make it work.?(my opinion)! Sand casting when done with petrobond sand and Aluminum, is relatively easy, and pretty cheap.? If you take a look at the FAME site (Florida Association of Model Engineers). You can see what I use and some projects I have helped with.? Click on "Gallery"? then look for "vertical single engine" and then click on the midget "works in progress" pictures, when you get there you will see a blue link to my casting pictures.? I posted a picture of my tiny furnace and some flask boxes and several pours. Given a good wooden pattern, almost anyone can turn out a good part with a simple?(propane) gas fired furnace and some old car?pistons. Get a copy of Steve Chaistin's book "Metal Casting Vol. 1" and Metal Casting Vol. 2"? Good stuff!!! If you guys come up with an engine, and you need some castings, I can?do them, my price is, I get to keep one set of castings?for myself.? I have done this before with a?few other MICE builders and it is fun and productive.? My only limitation is time as I have a full time job and two young children.? Therefore it could take several weeks or months before I output a complete set of good castings. I like the idea of a co-operative engine build.? Sure would stimulate the?group chat, and might keep us off all the?taboo subjects such as copyrights and piston rings, OH Shoot did I?just say that?? Hank ------- Re: One off castings Posted by: "hhelmenx~xxaol.com" Date: Fri Dec 14, 2007 8:55 am ((PST)) James, I sure would like to talk to you about investment casting.? I have made the "investment" but haven't been very successful in getting good quality castings.? There are several people in the MICE community doing it.?? ------- Re: One off castings Posted by: "James A. Lee" scriviamox~xxgmail.com Date: Fri Dec 14, 2007 9:36 am ((PST)) Dear Mr. Helmen: Just after answering, something clicked in my brain, and I remembered a nice little book on my shelf on the subject by James Sopcak (sic). It even shows you how to make all the needed equipment, though it is geared to jewelry making. All you'd need do is scale it up to the size of castings you're interested in. It's your lucky day...I happen to have two copies, so give me your address and I'll mail you one. ------- Re: One off castings Posted by: "mrehmus" editorx~xxmodelenginebuilder.com Date: Fri Dec 14, 2007 11:50 am ((PST)) In Min_Int_Comb_Engx~xxyahoogroups.com, "BillB" wrote: >Actually, 3D printing is not so expensive. Jerry James (HEX-2, 4) found a fellow on e-Bay that would print 2 cubic inches for $20 in 2 weeks turn-around. Note that it is 2 cubic inches of plastic, not pattern volume. If you shell the pattern drawing (patterns were done in 3D CAD) the volume of plastic is fairly low. Dimensionally, the printers range up to around 15 inch cubes for a work envelope. Jerry did a 3D pattern drawing for his HEX-4 and sent it off. 2 weeks later the pattern was in his hands in the form of two hard blue plastic patterns with a finish similar to that of 600 paper. Maybe Jerry will comment more on his experience. The CAD software he used was the free Alibre Design Xpress. Other sources for 4-cylinder designs include at least 3 engines published in Strictly I.C. over the years. At least one of these was a bar-stock engine IIRC. Look at the engines list on www.strictlyic.com if you want to see what they are. Right now we are investigating whether we can get a few crankcases created with a selective laser sintering printer. The crankcase, for a 1/4-scale Wright Brothers engine (the second design that sits vertical) would be very difficult to cast because of thin wall thicknesses. It would probably not be very cost effective to get into the kit business with a SLS printer as they cost at least $20,000 just for the printer. Phil Watt, the designer of the current Build Project engine in Model Engine Builder magazine, the SeaDog has a SLA printer that he rescued and rebuilt. All was fine until he ordered a load of plastic powder for it. $1800.00! And I thought ink for my ink jet printer was expensive. Today, one can buy a 3D printer for around $5,000 that will do somewhere around a 5" envelope. That would be good enough for most of us as the bits that come out of the printer can be glued together to make bigger bits. Not that I'm suggesting that $5,000 is affordable but then a new lathe or mill can cost quite a bit more than that. But I doubt that my wife would see it that way. Some day, the way engines are built will be far different from today. I can forsee the day when an engine and most other objects will be printed. No separate parts to be assembled, the engine will be printed with all the components inside and the entire unit will be sealed except for the power output and various ports for fluids and electricity. When it wears out, the whole thing will be recycled. ------- Re: One off castings Posted by: "jamesengine2006" jerryx~xxjamesengine.com Date: Fri Dec 14, 2007 12:25 pm ((PST)) As Mike said, I was looking to make a cast crankcase for the HEX-4 and found a source on ebay that would print a 3D part for me to use as a pattern. I HIGHLY recommend this method to make a pattern. I'm no expert pattern maker and wouldn't even consider myself an amateur pattern maker but using Alibre and a 3D printer was incredibly fast and accurate. The part was accurate to within a couple of thousandths. Z Corp actually sells a printer that will print a high temperature mold for aluminum casting - print the mold and pour the aluminum - will only set you back about the price of a new car - a nice car at that. www.zcorp.com The plan was to make mold halves out of Hydroperm, put the halves together and pour the aluminum. Hydroperm is similar to plaster-of- paris but is mixed with some additives so that it can be used to make mold cavities for pouring aluminum. The Hydroperm worked excellent as a liner for an electric furnace I built. It started to fall apart after about 15 melts but could easily melt 1 cup of aluminum in under 10 minutes - it was very fast - just not real strong. I've built all kinds of furnaces and the Hydroperm had to be the fastest and easiest to use - just won't last long. Jerry J. ------- Re: One off castings Posted by: "corey renner" vandal968x~xxgmail.com Date: Fri Dec 14, 2007 1:08 pm ((PST)) Jerry, I'm curious about your furnace design. Did you find plans on the web, or is it your own design? Have you got any more construction details? I wonder if molding the hydroperm around a chicken wire form might help it last a little longer (like really small rebar). cheers, c ------- Re: One off castings Posted by: "jamesengine2006" jerryx~xxjamesengine.com Date: Fri Dec 14, 2007 2:09 pm ((PST)) Corey: A little long but here it goes. I wanted a furnace that I could move around easily since I move every 2 years and am limited by the amount of weight I can move. That was the first design consideration. The second one was something that would melt fast and preferably electric. I've built the charcoal foundry, gas furnace (a couple of designs), Lil' bertha and the Hydroperm one. The problem with the electric ones are that you have to have some insulation. I've tried castable refractory and firebricks and they don't work for electric furnaces since they are non-insulative. The Hydroperm has lots of air mixed in so it's insulative. The problem is that the "shelf" or groove that holds the heating element started to crumble. Here is how I made it, this will at least be entertaining. I wanted to melt about a cup of aluminum, not ten pounds at a time since I would only be making small castings for engines. For the outside form I used a large stainless steel salad bowl - yes you can start laughing now :-) I poured about 2" of Hydroperm in the bottom with ¼ inch hardware cloth for reinforcement. When this dried I pulled it out and you now have a lid for your furnace. Then I used a disposable plastic bowl shaped like a cylinder for the inside form. I wrapped two layers of weather stripping on the outside of the inner form for the grooves. I used some #8 screws to go from the inner form to the outer form for the electrical connections, two of them. I then put the inner form in the outer form and filled the space between with Hydroperm. The inner form will float so you have to hold it in place. I used a stainless steel measuring cup for the crucible. If you use a perlite and furnace cement mix instead of the Hydroperm you practically can get everything from Wal Mart. I've heard of people winding a stainless steel wire heating element but I'm not sure how that would work. I added a photo under jamesengine2006. I put in a photo of the 3D printed pattern as well. Hope this helps. Jerry J. ------- Re: One off castings Posted by: "Carl Carlsen" kd7bfnx~xxearthlink.net Date: Fri Dec 14, 2007 2:29 pm ((PST)) I may have told this story before, but I'll repeat it. A bit over 2 years ago, I paid a visit to Bruce Satra of Morton Engine fame at his home and shop in Vernal, UT. It was a great lesson in "it ain't the tools you have, it's how you use them!" I looked over Bruce's mill, mold injector (self built), and marveled at what a 'simple' shop he had, but was even more impressed at what he could produce with the tools he had. Anyone who has looked over the Morton castings, know what delightful little castings they are. A couple of years back, he had orders for 10 casting sets ... which means 50 cylinders! LOTS of little castings in 10 engines! Almost as an afterthought, I asked, "but where is the foundry!" Bruce replied, "well, you are almost standing on the furnace" .... and here next to his driveway, was a pile of fire bricks, all tumbled down! He said, "I just set them all up and leave a little opening at the bottom for my burner," and he pointed toward a large 'weed burner' leaning against the fence. In the hands of a real craftsman, it doesn't take a lot of fancy do-dads! Carl ------- Re: One off castings Posted by: "BillB" wabit2x~xxgmail.com Date: Fri Dec 14, 2007 5:30 pm ((PST)) Thanks to all who responded to my questions about one-off casting. I'm going to have go over all the information several times. At first read lost foam looks very interesting. The results of lost foam I have seen were with the white beady foam and were very coarse with no fine detail. One off the top questions, how much smoke does lost foam make say for a one cylinder engine cylinder block that would fit in a 4" x 4" x 6" box ? Obviously the casting would only consume a fraction of that space. Maybe 10 cu in of casting. How bad does the smoke smell ? What minimum wall thickness is reasonable ? I have never see a lost foam pour, but videos range from some smoke blown away by a big fan to something that looks like a tar roof on fire. BillB ------- Re: One off castings Posted by: "Phil" ok_pcwx~xxyahoo.com Date: Fri Dec 14, 2007 8:38 pm ((PST)) So, as Mike mentioned, I am fortunate to own a zcorp z402 3dp powder printer. I haven't used it for any engine design work as yet, but have been wanting to get some work done in that direction soon. For the SeaDog design, I did it the old fashoned way; wood, putty, dowels,and sandpaper. I did use the modern technique of making a RTV rubber molds and casting expendable resin patterns for use on the pattern board. This way I kept the orginals from being damaged from ramming and can reproduce the matchplate with no loss of design dimension if such a future need arises. So back to 3D printing. It's amazing. I got the machine on a wish and hope and once home, found it to have major problems in every sub- system. The machine is undocumented to non service techs, and I had to reverse engineer it a bit to get it going again. I lead Mike astray a bit on the start-up cost of the machine. The first hurdle was the system software that is only available to owners with a current servivce contract, and at $5,000 a year, that wasn't going to fit any hobby budget. By some whining and praying, zcorp finally allowed me to have a one time copy for $500. The print heads are a bit expendable at 3 or 4 large parts per head. they are $120 each. I bought two. I can now manufacture my own from new Canon ink-jet print heads, a little bandsaw work, epoxy, a precisely cut centrifuge vial, and voiala a nine dollar and fifty cent head. cool. The binder solution is $375 a gallon, and you go through this basically at part volume rates (it drinks the stuff). I now make my own from a careful review of the MSDS's and a bit of ethyline glycol, glyceryn, and mostly water, and it's pretty cheap. The powder comes in two flavors; plaster and starch based. Whether you want a rigid part (infiltrated with epoxy or CA), or a 'lost wax style part' made of starch, and infiltrsted with wax (parafin). This stuff goes for about $500 for a plastic bucket about 2 gals. Wonderfully, 20 min thin-set plaster from home depot goes for about 8 bucks and works fantasticallylike the plaster style powder. At this point I haven't done anything much with the starch type except try it out; I still have a fresh unsealed pail to work with. If anybody has a 3d part that they would like me to play around with and see what comes-out, let me know by seperate email. I'd be happy to juice the machine up again and give it a try. Best Regards, -Phil Watt p.s. a shameless plug for SeaDog casting sets. It's a pretty cool little engine ( I know, I'm biased - smile), and Mike has done a great job taking all my chicken scratch and making a beautiful set of instructions. The foundry issues are out of the way, and I'm filling orders from stock. ------- Re: One off castings Posted by: "Edi & Rose Malinaric" emovix~xxmweb.co.za Date: Sat Dec 15, 2007 5:30 am ((PST)) Hi BillB - if you open... http://ph.groups.yahoo.com/group/castinghobbypictures/spshow/fd4c and squint at pic #6 you'll get some idea of the amount of smoke that lost foam creates. Smell is such that if you stand upwind of any zephyr you'll be OK. If not - it's still no big deal. I coated the steel crucible with drywall "slush" - no signs of any overheating or oxidation to be seen. As you can see there was no hi-tech in sight. Working and casting over a sand tray (dry sand) is the most important safety feature you could implement. cheers Edi ------- Re: One off castings Posted by: "billblackburnx~xxsympatico.ca" Date: Sat Dec 15, 2007 9:49 pm ((PST)) Hi Guys: Do you think there would be any benefit with pouring sand over the wet coat of drywall texture? (1) Dip foam in drywall texture. (2) Pour clean sand over wet drywall texture. (3) Re-dip foam in drywall texture. (4) Pour second coat of sand over foam. (5) Let dry and pour casting. Maybe one coat of sand would be all that is required? I think the sand would give strength to the coating. Willy ------- Re: One off castings Posted by: "Edi & Rose Malinaric" emovix~xxmweb.co.za Date: Sat Dec 15, 2007 10:20 pm ((PST)) Hi Bill - Drywall and sand makes a nice shell. Forget about dipping - you have to throw away too much of the "batter". Mix a small amount, brush it on, sprinkle sand over it, have a cuppa, brush on some more and sprinkle more sand and so on ... I went three coats and, after casting, found a few large flakes of the shell in the sand. Use the excess batter as a wash over the inside and outside of your steel crucible if you want to - seems to work OK. Word of advice - add vents! cheers Edi ------- NOTE TO FILE: I've read a lot about casting with the intent of learning enough to attempt some fairly simple stuff. While I have done lead bullet casting, I did not feel anything larger or more complex was really going to be part of my future. Then wow! I came across the following site while researching ideas for a home made CNC router: http://www.buildyouridea.com/cnc.html And during the photos of his model IG-88 build, there are steps where he clarifies what I had read before so that I now feel aluminium casting is practicable for my needs. Those processes are detailed on his page: http://www.buildyouridea.com/foundry/lost_foam_howto/lost_foam_howto.html While on this site, have a good look at his other projects and ideas. Lots of good stuff that could be adapted to our workshop needs. A very big thank you to Dave Kush for a truly fascinating and useful site. ------- Re: DIY Brass recycling [LitleEngines] Posted by: "Rupert" rwenig2x~xxxplornet.com Date: Fri Apr 4, 2008 6:57 pm ((PDT)) On Apr 3, 2008 John Sawicky wrote: >> Just curious. Do any of you "recycle" your brass? That is, do you melt down stuff and make some stock for a project? I have several pounds of brass from faucets and locks that I was thinking it might be interesting to melt it down and pour it in a mold. I've never done any foundry work (at least since high school in the 70's) so I really don't remember the temperatures required. I know, there's the issue of what kind of brass is it, impurities, etc. Thanks in advance, John << Hello John: You can melt brass chips and recast the melt into new castings or make round ingots for turning stock. There is a problem though -- the oil and other contaminants combined with the chips give off gases that are not good. Any other metal chips mixed in with the brass will melt too but you will get a mystery metal with unknown characteristics. Do I melt chips? No, I trade them in for clean metal of known alloy. Rupert Wenig Camrose, Alberta, Canada. http://www3.telus.net/public/rwenig/ [and in a later message] Two large metal casting groups that are active are: http://groups.yahoo.com/group/castinghobby/ http://groups.yahoo.com/group/hobbicast There are other groups but the ones I know of are not active. ------- 1947 Woodson and lost foam [LitleEngines] Posted by: "Ray and Ruby Brandes" rvbx~xxray-vin.com Date: Sun May 4, 2008 3:45 am ((PDT)) After a long hiatus from lost foam, I tried it again with disastrous results. I did it in loose sand pouring bronze at 2000F and only one piece was usable and that only because I could weld up a mis-run. Yesterday Ruby and I poured several more pieces and they all came out just great. What I did differently is this: I used flasks and lightly rammed the foam models (blue foam) using K-bond in the cope. Then I rammed the drag and cut sprues and runners and vents as if there was a hard pattern, but leaving the foam in place. Bingo! The castings turned out very well and today I plan to cast the standard which I see as the trickiest piece. Plans for this steam engine can be found here: http://www.vintageprojects.com/machine-shop/steam-engine-hobby.html Regards, Ray in FLA ------- Re: 1947 Woodson and lost foam Posted by: "Steven Haushahn" haushahnx~xxcatc.net Date: Sun May 4, 2008 5:44 am ((PDT)) Ray: I despise lost foam casting as I endured a brutally long and depressing run of failed castings trying that method. I didn't however try it with anything except loose sand. I will have to have another go at it like you describe. Thanks for sharing your experience with us. Incidentally I am presently building that same engine - it's my first try building a steam engine. I am not following the plans too closely but it retains its family resemblance. I made a wood pattern for the standard and rammed greensand. I migged in a repair in a small sink spot. It's mostly an aluminum engine. Was your repair to the bronze done with a TIG welder?. I recently acquired old TIG machine anticipating using it to salvage some brass and bronze castings. Trial runs indicate that I will be a while learning those skills. Steven ------- Re: 1947 Woodson and lost foam Posted by: "James Early" j.w.earlyx~xxworldnet.att.net Date: Sun May 4, 2008 6:25 am ((PDT)) The only way you can guarantee good results from lost foam is if you handle it in the same way you do lost wax. Coat the foam with plaster and then burn out the foam before putting it in the sand and then venting it properly. JWE Long Beach, CA ------- Re: 1947 Woodson and lost foam Posted by: "Steven Haushahn" haushahnx~xxcatc.net Date: Sun May 4, 2008 6:41 am ((PDT)) Yeah you're right, that works but my opinion is set, I don't like lost foam. You? Greensand rules. Steven ------- Re: 1947 Woodson and lost foam Posted by: "James Early" j.w.earlyx~xxworldnet.att.net Date: Sun May 4, 2008 9:03 am ((PDT)) The coating process works best no matter what type of expendable pattern used. If you are using multi use patterns then the rules change accordingly. For fine detailed parts some form of lost or expendable pattern works best. For large parts that will be massively machined then multi use patterns are the most desirable. JWE Long Beach, CA ------- Re: '47 Woodson Posted by: "KM6VV" KM6VVx~xxSBCglobal.net Date: Sat May 10, 2008 4:15 pm ((PDT)) Ray and Ruby Brandes wrote: > I continue to make progress on the Woodson. A couple of > new photos are posted at: > http://www.foundry.ray-vin.com/woodson/woodson.htm > Regards, Ray in FLA Very nice work Ray! Impressive castings. Do you find it difficult to handle the 2000 Deg bronze? Alan KM6VV ------- Re: '47 Woodson Posted by: "Ray and Ruby Brandes" rvbx~xxray-vin.com Date: Sat May 10, 2008 5:59 pm ((PDT)) Alan: The crucible of bronze is pulled from the furnace using lifting tongs and then poured with a two-man pouring shank. The wife and I use face shields which protect us from the infra-red. I have aluminized gloves because I do the skimming and adding the magic dust. The most uncomfortable time is when the furnace is open. We have done close to 100 pours over the years and have it down cold. The first few times, and any time we change anything, we do a cold rehearsal. It is a lot easier to clear problems cold then when hot. Regards, Ray in FLA ------- Mini Foundry [taigtools] Posted by: "Shad" shendersonx~xxthegeekgroup.org Date: Wed May 14, 2008 6:46 am ((PDT)) Hi All: There's been a fair amount of interest in the mini foundry. Since it's somewhat off-topic for this list, I'll do a writeup and post in the [taigtools] files section for others to read. The writeup will cover - SAFETY! Construction of the mini (1/2 lb, 5 cu in) foundry Construction of the not-so-mini (3lb, 30 cubic inches) foundry Design of the 10lb (100 cu in) foundry Propane burner construction Crucibles, tools, and setup Lost Foam Castings SAFETY! Please give me a little time, as I'm recovering from the "creeping crud" that's going around the office. I also intend to include lots of pictures in the writeup. Thanks for the interest! Shad H. ------- Re: casting? [LittleEngines] Posted by: "Mike Duffy" duffymfxx~xxyahoo.com Date: Tue Jul 1, 2008 2:52 pm ((PDT)) Gordon wrote: > A friend of mine just dropped off two large ceramic kilns with electric > heaters. The name plates say that the will go to 2300° so that should > be hot enough to melt aluminum or brass. Will these work for melting > aluminum or brass for castings? The price was right. He paid $50 and > I have use of them for nothing. They will work. I used to use a 220 volt 30 amp electric kiln to melt bronze and aluminum. Problems - There were wound metal elements inside the oven (like the glowing coils in a bathroom heater) that shorted out if a piece of slag or other foreign matter landed on them during the melting process. It would take about an hour to melt a 2 to 3 pound block of brass. When the furnace was hot I could melt another 2 to 3 lbs in a half hour. When the elements shorted out I initially bought new ones at a cost of $20. each. I eventually found out the maker of the wire. Turned out to be Hoskins Alloy 875. I bought a large spool of the wire and wound new elements using a mandrel in a lathe run at a slow speed to wind a new element. This (I estimate) brought the cost of an element down to about 15 cents. The second problem - was the high cost of electricity. Eventually I gave the furnace away as it was too expensive to run. If I get back into metal casting it will be with some kind of charcoal, propane or other gas fired unit. Mike in So ------- [Metal_Shapers] Casting ala Gingery -- Belt cover for the Porter Cable shaper Posted by: "pacer8020" pace8x~xxbellsouth.net Date: Wed Nov 12, 2008 1:12 am ((PST)) When I introduced my "new" Porter Cable shaper a couple weeks ago, I told that it was missing the upper belt cover that was originally a cast piece. Having built about everything that Dave Gingery dreamed up for his series on building a workshop out of scrap aluminum, I felt like this cover would be a good refresher course. With help from Ed Godwin in the group here I found a sketch with the diminsions of the cover and a copy of an original parts manual with a good pic of it in the files here,--- so it looked like not too big a deal--HAH!! Well it was quite a learning experience -- that it is a bitch of a pattern to try and get out of sand, -- that I had to make a second pattern to correct the many errors I kept finding on the first one, -- that my sand from back in the Gingery days was apparently 'wore out' and to replace it. Once I got the pattern re-made and the new 'dirt' came in yesterday, I promptly set about to make the 9th attempt to pull the pattern and make a pour!! The new 'dirt' was amazing! what a difference -- and with the new pattern, I succeeded on the first try, had it completed in about 2 hrs. Got it painted and put in its new home today. Heres some shots of the process--- Just coming out of the sand, -- my eyes popped out when I saw this much...it just might come out all right!! http://i22.photobucket.com/albums/b301/pace1980/Porter%20Ca ble%20shaper/PorterCableshaper001.jpg Completely out of the sand and YESSIR shes lookin good!! http://i22.photobucket.com/albums/b301/pace1980/Porter%20Ca ble%20shaper/PorterCableshaper002.jpg Laying side by side, pattern and 'clone' ready to be painted http://i22.photobucket.com/albums/b301/pace1980/Porter%20Ca ble%20shaper/PorterCableshaper005.jpg And here she is residing in its new home --- sure did improve the looks of the little guy. http://i22.photobucket.com/albums/b301/pace1980/Porter%20Ca ble%20shaper/PorterCableshaper006.jpg ------- Re: Casting ala Gingery -- Belt cover for the Porter Cable sh... Posted by: "rgsparberx~xxaol.com" Date: Wed Nov 12, 2008 5:20 am ((PST)) pace8, You are a master craftsman and an artist! Your results are first rate. Got lots of questions. How did you make the curved part of the pattern? How did you make that classy arrow? What prep did you do on the aluminum before painting? What brand of paint did you use? I see the fresh Petrobond and know the feeling. I changed mine this year and was equally amazed with the results. I changed after my 10th drop out using my worn out Petrobond. I still plan to have it rejuvenated but must bring it to a friend with a muller. Rick Sparber web site: http://rick.sparber.org ------- Re: Casting ala Gingery -- Belt cover for the Porter Cable sh... Posted by: "pacer8020" pace8x~xxbellsouth.net Date: Wed Nov 12, 2008 7:06 am ((PST)) I'll resend them with tiny url... http://tinyurl.com/5dmt3b http://tinyurl.com/5nopsa http://tinyurl.com/6rjmsd http://tinyurl.com/6jdq7c Now Rick, to your questions... The curved part -- well another pic is probably the best way to answer that: That piece was the booger to get pulled from the sand!! http://tinyurl.com/5lyt2p The little arrow: That's soft white pine I'm cutting the 'U' shape from and I just took a small piece of it and rough bandsawed the shape, and then Dremeled & filed the shape, glued it on and globbed the spackling on! The 2 raised lines are 3/8 dowel split lengthwise on the band saw, glued on and spackling applied. Paint: As you probably are only TOO aware, Al can be a pain to paint and have it stay on, and I don't have any magical method. I just put a light coat of rattle can primer on it and used a little spackling putty to fill in some of the worst voids/bubbles, dusted it with a little more primer and shot it with the spray gun. The one thing that seems to help is to not get a lot of paint build up, as you know, it chips so badly on Al. email me if you wanna bat it around some more. ------- Re: Casting ala Gingery -- Belt cover for the Porter Cable sh... Posted by: "MICHAEL BAKER" mickeybakerx~xxbtinternet.com Date: Wed Nov 12, 2008 4:49 pm ((PST)) Hi, nice job on the casting. As for painting aluminium I think you need what is known as 'etching primer'; this actually bonds chemically to the surface and gives a secure base for your paint. Most automotive paint suppliers will have it. Regards, Mike ------- Re: Why make a casting? [sherline] Posted by: "Michael Jones" mwjones99x~xxmac.com Date: Sat Apr 25, 2009 8:39 am ((PDT)) "mrbillk2" wrote: > Hello everyone. I'd like to make a live steam model engine. I'm still in > the research stage, sorting out the ones I think I can do from the many > interesting ones. I'd like to start with an interesting success. I take it from what you write below about drive wheels that you're thinking of a model steam locomotive. To get involved in building live steam locomotives you'll need to consider a variety of factors, including where you'll run it, how heavy will the finished model be, how many of the parts can you make with your own machines, etc. If you want to make your first steam project a success, then my suggestion would be to start with something that's achievable and satisfies you. You'll then have a working model (steam or stationary) and from completion of that, you'll be able to draw on your experience in choosing a more challenging follow-up project. > I've been reading books and looking at plans. I've noticed that some > instructions say to make a casting and send it off to a foundry to have > the large main drive wheels made out of cast iron. I don't know what the > advantage to doing it this way would be. I also know that just because I > can't think of a reason doesn't mean that there isn't one. I've made quite a few patterns for steam locomotive castings (wheels, axleboxes, hornblocks and cylinders) which I've had cast. The reasons are the time it takes to machine each component from solid with a lightweight machine like a Sherline. When you start with a lump of cast iron, you're paying for a solid chunk which you're going to carve into something that might have half its weight in the finished part...but you paid for all the iron or steel to start with. Here's an example. I made a pattern in polyurethane board for a locomotive wheel. It took my CNC Sherline mill about 6 hours to carve all the detail and required several changes of cutters. The end result was a pattern that could be used directly by the foundry which then cast 10 wheels. Because I could ramp up the speed of the machine for a softer material than cast iron, the job was completed much faster than if we had been carving the wheels from solid which would have taken much, much longer. With a casting you're paying mostly for the material (by weight) that's in the casting. You're not paying for a lot of extra material that you're going to machine away. > My guess is that without a CNC mill the spokes are hard to make. The shape of the spokes is hard to make if they happen to be oval cross- sections in the prototype. They can be made without CNC, but it's hear- tbreaking to make a slip-up after a lot of machining has been completed. Surprisingly, with some fixtures, it's easy to make these profiles for spokes in wood and then assemble them in the pattern, but you still have to blend them with fillets to the other parts. That can be hard to achieve good results and all the imperfections will be seen in the casting, so the patterns have to be right. > Could that be the only reason? Strength or weight wouldn't be an > issue, would they? The principle reason castings have been used in the past is cost. Even with conventional pattern making (using wood patterns, core boxes), etc., it's been cheaper to have castings made that to try to hog the component out of a lump of material. There are other factors, too, related to why castings were traditionally used, but I won't go into those for now. >Cast iron is a little harder to machine then steel isn't it? Cast iron has traditionally been used because it was cheaper to make castings from compared to other materials. Steel castings have always been more expensive and harder to obtain. C.I. machines very nicely, but produces a lot of grey dust which is quite abrasive. Steel is harder to cut and Sherline machines are probably not the best to use if you have to remove a lot of material. I wouldn't consider making steel wheels from the solid for a steam locomotive on a Sherline (depending on size). There is a outer skin on iron castings that needs to be removed during the first pass. Continuously cast iron (durabar) doesn't have this skin. > Anyway I thought I'd ask the most experienced machinists and modelers I > know of. Thanks for your time. My advice would be to consider a model locomotive design that is supported with castings at least for the wheels and cylinders. When you gain experience machining you'll be able to judge whether you want to tackle a project which requires you to make patterns. Get on with building the model, not worrying about making the patterns, too. Just a few thoughts. Regards, Mike Jones Cardiff, Wales ------- Re: Why make a casting? Posted by: "Ron Ginger" rongingerx~xxroadrunner.com Date: Sat Apr 25, 2009 9:00 am ((PDT)) First reason is to make an accurate scale model, if the original was a casting you likely want a casting for the model. Bar-stock parts often look 'clunky' when compared to the original engine with smooth, flowing cast parts. Some parts are cast for economy of material- I once made a coupling for a tug boat that took a 35 pound round bar and made an 18 pound part- and a huge pile of chips. Would have been better to make a cast part. Some castings have hollow insides -- like water jackets on IC engines. Darn hard to make inside hollow parts from solid bar. For flywheels weight is important, so cast iron is best. But you can buy solid cast iron bars and machine the parts from that. It is beautiful stuff to work with. I made the spoked wheels on a locomotive from it. All that said, there are some fine models made from bar stock. For a whole line of engine models made without casting see Ray Hasbrooks models and plans at hasbrouck.8m.com ron ginger ------- Re: Why make a casting? Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Sat Apr 25, 2009 11:11 am ((PDT)) Hi Bill: Locomotive or stationary engine? In either case, you may want first to get some experience with one of the casting kits from PM Research, or other supplier. http://www.pmresearchinc.com/store/home.php?cat=4 These are great little casting kits, lots of fun, good experience, and very fine looking and running engines when completed. PM and others also sell cast bronze flywheels for finishing. I use them on my bar stock engines. Cast bronze machines very easily, as does good quality cast iron. I've never had a problem with PM's castings. DC David Clark in Southern Maryland, USA ------- Re: Why make a casting? Posted by: "n2562001" jlkiefferx~xxcharter.net Date: Sat Apr 25, 2009 5:32 pm ((PDT)) Bill: In general I would agree with everything that has been described and suggested. As I see it, Model Engineering Models tend to fall into three categories. Freelance, generic representations and exact scale. For the first two categories models can many times be built around available castings saving much machining. Many castings are available through the various model engineer supply houses. Items such as basic simple wheels are an ideal CNC project but many are also machined manually with little difficulty. As several have indicated the larger the part the more practical a casting becomes reducing machining. On the other hand, if you decide to build an exact scale model it will be a whole different ball game. Personally I have yet to see a casting set that was to scale for anything under about the size of a five gallon bucket. While small high quality high detail castings are available, they are also very expensive especially for small runs. They can of course be machined to scale but it usually ends up being more work than machining from bar stock or fabrication. If you plan to build a exact scale model under about the size of a small loaf of bread, you will find machining from barstock to be the most practical 99% of the time. With few exceptions almost all parts will be one-off. Much time and machining can be saved by fabricating a part by silver soldering and or welding several parts together to make one part. In addition a bead blaster can be used to clean , texture and final form the part to dulicate the original. Since you referenced a wheel I will give an example. I have posted a photo under my name of a flywheel with round tapered "S" curve spokes. While certainly possible on an expensive commercial CNC system, it would not be practical as a one or two off item when compared to simple and accurate fabrication. It was constructed as follows. First the hub was turned with spoke holes drilled. Next tapered spokes were turned straight making the taper very accurate, simple and fast. Then two rods with the correct radius were clamped in a vise with proper spacing. Since the spokes were left longer than need be, they were all grabbed together on each end with two vise grips. From that point they were easily wrapped around the two rods in the vise forming the "S" curves in less than 60 seconds. Since they were all done together they were all identical. From that point the spokes were silver soldered in the holes on the hub. The ends of the spokes were then lightly machined to diameter to fit the machined outer rim and checked for spacing. Then of course each spoke was silver soldered to the rim. As mentioned everything was then blended and final formed in the bead blaster. Bright surfaces were then machined and polished before and after painting. Jerry Kieffer ------- ZA-12 Casting - corroding steel [Min_Int_Comb_Eng] Posted by: "jamesengine2006" jerryx~xxjamesengine.com Date: Sat May 23, 2009 2:10 pm ((PDT)) New development today - or rather big mess. I'm using a pan in a melter to melt the ZA-12. This is about the 10th time using this pan. Today a hole developed in the bottom and dumped the ZA-12. I have safety procedures so no safety issue. I took the melter apart and a hole had eaten through the bottom of the pan. Anyone know if ZA-12 (mostly zinc) will corrode steel and eat through it? Zinc is used all the time to coat steel so I'm at a lost to what is going on - except my casting machine needs a rebuild. Thanks Jerry J. ------- Re: ZA-12 Casting - corroding steel Posted by: "Jerry Kimberlin" kimberlnx~xxcomcast.net Date: Sat May 23, 2009 2:18 pm ((PDT)) >Anyone know if ZA-12 (mostly zinc) will corrode steel and eat through it? Probably the aluminum in the ZA-12 alloy. Aluminum will eat up iron pretty easily. It will also get a bit poisoned by the iron, so it may not be too good for the ZA-12 if too much iron gets added inadvertently. JerryK ------- Re: ZA-12 Casting - corroding steel Posted by: "Gail" nmsteamx~xxcomcast.net Date: Sat May 23, 2009 3:25 pm ((PDT)) Jerry, ZA-12 will dissolve steel quite well. ZA-8 is used in cold chamber casting machines to help preserve the life of the molds. Most stainless steels work quite well with ZA-12. My ZA-12 pot is cast iron and that has worked well. I have been using the same pot for over 20 years with no sign of wear. It has been emptied out several times, and each time I have sprayed it with graphite as a precautionary measure, but I don't think that was really necessary. The low pressure hot chamber die casting machines that I know about use cast iron. Gail in NM,USA ------- Re: ZA-12 Casting - corroding steel Posted by: "Jerry James" jerryx~xxjamesengine.com Date: Sun May 24, 2009 1:07 pm ((PDT)) Gail/Jerry K Thanks for the info. I was using a Lee production pot with a bottom pour. It was working great until the hole developed. It was about ¼" diameter. I have a bigger cast iron pot that I sprayed with the graphite - maybe should have used some on the Lee pot :-) I'm off to the hardware store to get some steel pipe - see how that holds up. Jerry J ------- Re: ZA-12 Casting - corroding steel Posted by: "Jerry Kimberlin" kimberlnx~xxcomcast.net Date: Sun May 24, 2009 3:02 pm ((PDT)) Well, people who use steel pipe say that it doesn't hold up very well either - on aluminum. Most say they get added longivity by using kiln wash or a ceramic liner made from refractory. Since Zamak melts at a lower temp than aluminum, I would expect the steel pipe to last a little longer, but see no reason not to spray in some graphite or use kiln wash or something as an assist. JerryK ------- Date: Sat, 17 Oct 2009 21:27:35 -0700 From: "Bill Taggart" Subject: [OldTools] Very worthwhile casting thread over at Wooden Boat Lots and lots of detail, good photos, a whole explication of the process, replete with trial and error and error ... http://www.woodenboat.com/forum//showthread.php?t=88357 Be sure to make it to the end - even if you just skim the stuff in between. At least look at the photos. Bill T. ------- Casting [sherline] Posted by: "Ron Ginger" rongingerx~xxroadrunner.com Date: Wed Feb 3, 2010 6:46 am ((PST)) >> Hi David, >> > If you could still give some hints on the moulding please. >> > I am more interested in that than the gib. Many Thanks, Hamilton > Good Morning Hamilton, > I can't top these: > http://www.alumilite.com/index.cfm > http://www.freemansupply.com/video.htm > Lots of excellent instructional videos. Freeman Supply offers a sample kit for about $40 that includes several of the machinable plastics and some RTV and casting resin. It also has a great video that shows many good techniques. Smooth-on.com supplies a huge array of resins and rubber- they are somewhat aimed at the art world but still very useful to modelers. They have some local dealers that offer seminars. I took a one-day seminar in Boston last year that was excellent. They demonstrated several molds and processes. The seminar cost $50, but you got a $50 sample kit at the end of it. I've made several RTV molds and investment cast parts. It's a great technique to learn. ron ginger ------- NOTE TO FILE: The following casting related links came out of a discussion on making one's own lathe pulleys since original parts can be very expensive or difficult to find. Interesting reading, with some useful tips on casting, cutting metal, and machining. ------- Re: motor pulley for 12" lathe [atlas_craftsman] Posted by: "dougrl3x~xxaol.com" Date: Mon Mar 8, 2010 7:13 am ((PST)) Here is a guy who made his own and then machined them on the lathe, so, if you are lucky enough to have the resources to cast your own, then machine them down, there you go! A lot of work, but an interesting read and how-to, be sure to read each part / link at the bottom of the page. http://www.backyardmetalcasting.com/castingpulleys1.html Doug ------- Re: motor pulley for 12" lathe Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Mon Mar 8, 2010 7:29 am ((PST)) Here is an alternate way to make your own pulley: http://rick.sparber.org/Articles/CD/CDM/pma.pdf Rick ------- Cast iron repair [atlas_craftsman] Posted by: "woolfgeo15" weldon.hammondx~xxutsa.edu Date: Sat May 1, 2010 5:46 am ((PDT)) Can anyone recommend a someone for casting small parts in cast iron and welding of broken cast iron parts for antique tools? Thanks ------- Re: Cast iron repair Posted by: "Jim Ash" ashcanx~xxearthlink.net Date: Sat May 1, 2010 5:55 am ((PDT)) There's a foundry in Pennsylvania called Cattail Foundry that is known to pour one-off's for the model engineering folks. I've seen their castings and they know their stuff. http://www.simmeth.com/wjs_1/cattail/index.htm ------- Re: Cast iron repair Posted by: "Russ Kepler" russx~xxkepler-eng.com Date: Sat May 1, 2010 6:59 am ((PDT)) Cattail Foundry in Pennsylvania has done good work for me. They don't do repairs but can cast new from broken castings. They're an Amish outfit so don't expect the phone to be answered in fewer than 10-12 rings (if at all). Cattail Foundry Emanuel J. King 167 W. Cattail Road Gordonville, PA 17529 (717) 661-9172 There are others on this link: http://wiki.owwm.com/Default.aspx?Page=FoundrySources ------- Re: foundry work needed [Min_Int_Comb_Eng] Posted by: "boiler_room_machine_works" tvaughanx~xxneo.rr.com Date: Sun Oct 3, 2010 2:39 pm ((PDT)) hhelmen wrote: > Does anyone know of a foundry that will cast iron from small loose patterns in the Eastern US? I met a gentleman in York Pa. who had some train wheels done nearby, but have lost his contact information. Hank < Hi Hank, I can recommend working with Dave Clark clark5x~xxzoominternet.net Dave will cast in iron, bronze, brass, aluminum or special alloys. He can also make and repair patterns if needed. He has been helping me with a number of parts and his service/quality is very good. Located in Medina, OH. (Usual disclaimers.) Tim ------- Aluminum swarf [taigtools] Posted by: "mbonfire2002" mbonfirex~xxhotmail.com Date: Thu Nov 18, 2010 1:56 pm ((PST)) Maybe someone can confirm this but I think I read somewhere that using swarf for casting is not advised...I believe the concern was that the considerable surface area to mass ratio of swarf resulted in lots of oxide (and other contaminants) per pound of metal leading to poor castings. If so, that would imply that the swarf scrap would need to be purified before it is used for casting. Truth of urban legend? ------- Re: Aluminum swarf Posted by: "Shad Henderson" ogberix~xxgmail.com Date: Fri Nov 19, 2010 7:22 am ((PST)) Swarf can be used for castings, but there are a few caveats. First, it must be compressed into a fairly solid "puck" to exclude as much air as possible. As you said, swarf has a high surface area to volume ratio, so it oxidizes nearly instantly when dumped into a crucible. Secondly, it's usually contaminated with cutting fluids. At best, these simply burn off with a stink and some smoke. At worst, they explode into vapor in the intense heat, scattering the "puck" and possibly flinging molten aluminum everywhere. Third, while they can be melted, they need to be dumped in and submerged in a heel of molten metal to prevent too much oxidation. Lastly, it's probably swarf from an extruded aluminum. This aluminum machines well (usually), but makes for poor castings due to its low silicon content. I don't bother with melting swarf. Too many drawbacks for the surprisingly small amount of metal it produces. I also strive not to mix up my real cast aluminum scrap with my extruded aluminum scrap. Cast aluminum generally melts and casts the best, as it's got silicon already in it to improve fluidity. A fresh casting is most always "annealed", though in a few months they harden to about T2 temper. It's possibly to heat treat them to a higher temper, but generally that's out of the reach of the home foundry user. Instead, we simply beef up the part a little for extra strength, or simply don't use home castings in a situation where failure could mean death or serious injury. As for cleaning the melt, I use Morton's Lite Salt to gather up the dross (aluminum oxides). About a heaping tablespoon wrapped in a piece of aluminum foil dropped into the melt causes the dross to stick together, where it's mechanically removed with a slotted spoon with an extra-long handle. After that, I drop in a heaping tablespoon of granular pool shock wrapped in aluminum foil, and use the spoon to hold it on the bottom of the crucible. The sodium hypochlorite reacts chemically with the aluminum, removing extra hydrogen from the melt. Stand upwind and be careful, as the by-products of this are chlorine gas and hydrochloric acid. Once the melt stops bubbling, I skim it once more, then do my pour. The pool shock removes hydrogen from the melt. If this step isn't done, you'll likely end up with hydrogen porosity in the casting. This is evident by tiny little "pinholes" throughout the casting when machining it. Contrary to popular belief, you don't need to "stir" the melt. I poke around a bit with a metal bar to make sure there's no chunks, but that's about it. Stirring introduces hydrogen into the melt, so it's counter-productive. Also, it's worth noting that aluminum and magnesium both look alike, weigh about the same, and you'll find both in cast form. The simplest method to determine what it is: Clean off a spot with a file, wire brush, etc. Get down to bare metal, then put a few drops of vinegar on it. If it does nothing, you have aluminum. If it fizzes and/or turns black, it's magnesium. There are some almag alloys out there, so if there's any reaction, it's best not to try melting it. If you *do* accidentally get some magnesium in the melt, and it ignites, the only thing you can do is shut down the burner and start gently shoveling sand onto the burning mess. Magnesium fires are scary. And for the love of Mike, once it's out, leave it be for 24 hours. If you poke around while it's still hot, it could re-ignite. And it'll take *quite* awhile to cool off if it's entombed in sand. It's possible to cast magnesium in a home foundry, but the advantages of it are far outweighed by the dangers of having a 10 lb crucible of highly reactive molten metal that can burst into flame, and is nearly impossible to extinguish. Stick to aluminum. Once you start casting your own parts, you'll wonder how you got along without doing so! Need a 3x3x3 block of aluminum? You can cast that. Pattern making is just as addicting as whittling parts out of billet. Perhaps moreso, because sometimes you'll dream up of nearly impossible shapes to make. Hope it helps! ------- zamak castings? [Min_Int_Comb_Eng] Posted by: "Ken , VK7KRJ" vk7krjx~xxusers.tasmanet.com.au Date: Sat Dec 4, 2010 1:43 pm ((PST)) Hi, I am thinking of using one of the zamak alloys to cast the head, block and crankcase for a single-cylinder test engine of 40cc. Does anyone on the list have any experience of using zamak for this purpose, or general thoughts on it's suitability for this? I was thinking maybe za12 or za27. I would think a steel or cast iron cylinder liner would be needed, but what about the other bearing surfaces - would bushes be needed or does zamak handle the bearing function ok? Any thoughts, opinions, etc will be appreciated. Cheers, Ken www.vk7krj.com ------- Re: zamak castings? Posted by: "jamesengine2006" jerryx~xxjamesengine.com Date: Sat Dec 4, 2010 2:29 pm ((PST)) Ken, I have cast several parts with ZA-12 and love it. You can melt it at much lower temperature then aluminum and can use common lead melting (bullet casting) equipment. It will corrode thin metal containers so stick with cast iron pots - been there and done that. You can use a turkey fryer burner and cast iron pot easily. Many are concerned with zinc fumes but you would have to heat the ZA-12 well above the melting point. I melt and pour at around 475C to 525C - the higher temp for thin wall castings. From what I've read on the net, zinc fumes at above 900C. I have never had any ZA-12 fume. ZA-12 has the strength of cast iron. It has bearing properties similar to bronze so it makes excellent bearing material. It is also VERY easy to machine and cast. There are three down sides vs aluminum. It is heavier than aluminum which shouldn't be a problem unless you plan on putting the engine in a model flyer. It should only be used in "lower" temperature applications. You shouldn't use it for pistons or cylinders - definitely use a liner. The last one is that the casting will end up looking like pewter - a dull grey finish. I purchased some plating kits from Caswell but have not used them yet to see how the finish turns out. Hope this helps. Jerry J. ------- Date: Wed, 25 May 2011 14:19:24 -0700 (PDT) From: gary may Subject: [OldTools] the age of bronze gentle galoots You may recall that a friend of mine, one Den Fandrich, is up and running with a small and quick bronze foundry here in South Seattle: JLA. The inaugural pour was the last sculpture of the late James L. Acord, co-founder. Den's made several pours of ingots, reducing scrapped copper pipe and faucet stocks---whatever---into a "house" bronze for general use--he's also gleaned several tons of top-quality scrapped bronze castings over the years, being eagle-eyed and lodestone-like for the stuff and spending two decades at the center of Seattle's art-foundry industry. Times being what they are, the market for bronze sculpture is somewhat sporadic, in short, here's an opportunity to get some cast bronze artifact(s) at a rock-bottom price. JLA was designed with this accessibility as a primary goal, so it will always be the most reasonable and most accomodating foundry in the US; right now is a good time to consider one-offs and small production runs. I'm working on a generic chariot plane casting, myself, and working with Den on a recipe for gunmetal, which is something the foundry will stock in a house recipe and also something that can be cooked up to spec, 125 lb at a time. IOW, if you know exactly what you want, here's the place to get it, bronze-wise. Investments ready to pour that can hang around waiting for left-over bronze?---now's the time. I know nothing about investments. I *do* know that wax and balsa models can be encapsulated into a cementitious pudding that is 'burned out' in a kiln; the pudding hardens in the kiln (as the model burns away) to become a mold that receives molten bronze. For a consistent series of castings, there are numerous approaches, none of them fully understood by me. Den's explained it to me like this: "Make the goddammed model." This is what I know. If you wanted to make a production run of identical bronze castings for lever-caps and/or screws, trammel points or infill bridges, or anything you wanted around 100lbs of at a time, JLA is where you should go. If you have a dream casting you want just one of, JLA is ready to do it. In Den's house bronze, which is nice stuff, these items will gleam. I don't think pure bronze is the right stuff for plane body and sole castings, but when Den has the gunmetal cooked up, it'll be exactly the right stuff for any and all wood contacting tools, leaving no tracks or traces behind. Sadly, I have no financial interest in JLA. No financial interest will attach to me if you go there. Putting you in touch with Den does not make me involved, etc etc. JLA is working on a website: http://www.jimlacordbronzefoundry.com/gallery.htm It may contain everything you need to know. best to all galoots, everywhere--- gam in Seattle ps--please "reply all". pps---to Lee---don't know if sending email to Mojoe44 gets to Den or not, less'n you do it. If you get a bunch of responses from galoots all over the world, and I hope you do, will you pass them on? ------- Re: updated article: Making Square Holes, version 3 [Metal_Shapers] Posted by: "Rexarino" rexarinox~xxgmail.com Date: Fri Apr 20, 2012 4:35 pm ((PDT)) On Tue, Apr 17, 2012, Rick Sparber wrote: > This article continues to grow as more people send in their low tech > tricks for making square holes. If you are interested, please see http://rick.sparber.org/msh.pdf Since my favorite hobby is casting metal, I'm surprised I forgot to suggest that one could cast a tool. Place an outer tube to hold the casting medium of choice, make a bottom that will resist the medium, and allow a square sacrificial blank to protrude up inside the tube to the depth required. For instance, to cast an aluminum/zinc socket, the tube could be a short section of pipe or EMT tube, the base can be a sand-clay mix, and the sacrificial square can be anything that won't melt, covered by a thin wrap of steel or heat resistant "fiber paper" as a release agent, http://shop.bullseyeglass.com/fiber-paper-1-16-thin-x-24-wide.html or copper foil http://shop.bullseyeglass.com/metal-foil-copper-1-10-ft.html as a liner that will stay with the casting. Heat up a small can of aluminum scraps with a torch, pour into the mold (DRY THE MOLD THOROUGHLY FIRST!!!! Use the torch or an oven, if SWIMBO "approves - - -" ) and there's your wrench. Casting plastics, filled epoxy, Bondo with lots of metal shavings or fiberglass included - all would work, especially if a piece of steel were wrapped around the square mold for a wearing surface. It would be reasonable to rough up the inner surface of the pipe first. Rex ------- Date: Fri, 11 May 2012 23:05:47 -0400 From: Darrell & Kathy Subject: [OldTools] yet another great time waster project Galoots, Well, it ain't woodworkin', but I used some old tools. I kind of collect random junk. Any of you who has visited my shop knows this. Last year I was at St Hilda's Church "Free Market". It's like a rummage sale but everything is free. They do pass the hat around, and everyone drops a few bucks in. Good fundraiser. And a good way for some people to rid themselves of a lot of random junk. Also good for *me* to acquire said junk. Like that handful of pewter mugs. You know the ones, they say "Bob" or "Dave" on them and have glass bottoms. Recently one of my wife's friends gave her a box of stuff, which would otherwise have gone to the dump. Mixed in with the stuff was some random junk. I took one look and said "Mine!". Now I had a nice hunk of soapstone. The wood for those new closet doors I'm supposedly building is sitting in the shop. Acclimating. Right. Better get to work on those doors, eh? Nope, not when I can play with molten metal! I recalled one of the stories Esther told us about her SCA friends casting pewter, and I decided that this was something that would waste a lot of time whilst I actually appear to be doing something useful. I sawed the soapstone in half, tossed one piece in the "interesting scrap" box, and cut the other piece in half again. This isn't your nice fine grained reasonably hard soapstone, nope, it's the really soft stuff. I barely spent 30 seconds cutting the stone with a dull hacksaw. Dragged out the plate glass with some old adhesive backed 220 grit sandpaper on it and lapped the faces of the blocks so they were a good match. Off to the A.B. Jardine post drill with a big forstner bit to cut a neat circle in the face of one block. Then my ineptitude came to the fore. Carving a fleur-de-lis inside the circle. Awful. Simply awful. But it beats jointing and thicknessing those door frames, so I figured it was good enough. I carved a roughly conical hole in both halves of the block, and it looked like a mold. I rummaged around the scrap metal bin and found some of that pewter and a coffee can to use as a crucible. Time to go out to the garage and haul out the casting furnace. OK, for pewter all you need is an old camp stove. This one I picked up off the curb about ten years ago I think. Or was it the one I bought at a yard sale for $5 (which came with a gallon of fuel :^) Whatever, it still works. http://galootcentral.com/components/cpgalbums/userpics/10074/pewter_cru cible.jpg Crank it up, melt the pewter. I used a hand screw clamp to hold the two halves of the mold together. Pour it in, wait a few seconds until the metal goes from shiny to dull, and then take it out of the clamp. I was not sure how the stone would react to all the heat, so I wore a full face shield, and had a bucket of water outside to cool off any overheated body parts. Nothing went awry so far. http://galootcentral.com/components/cpgalbums/userpics/10074/pewter_mo ld.jpg The first batch were really thick, because of the depth I bored to with that forstner bit. Almost always a void at the tip of the fleur de lis. I lapped the mold back a bit on the sandpaper and tried another batch. This time they were so thin the metal cooled too quickly, and would not fill the mold. Once I got the rock hot enough it started to cast OK. Back to the shop to deepen the mold again, and mess with the shape of the design. Messed it up even worse. Pours better now, a medium thickness (1/8 inch I would guess). Always gets this stripe where the hot pewter enters the mold. I don't how to fix that yet. http://galootcentral.com/components/cpgalbums/userpics/10074/pewter_me dallions.jpg I think I will cut the other piece of stone in half and bore them as blanks. We'll see if any of the Scouts in our troop want to try carving a design. I just need one backer block for any number of medallion designs. Betcha the kids will have fun at the badge-trading tent with a pocket full of commemorative medallions at the Fort George camp next fall (www.sbfg.ca). Darrell LaRue Oakville ON Wood Hoarder, Blade Sharpener, and Occasional Tool User ------- Date: Sun, 13 May 2012 20:24:01 -0700 From: scott grandstaff Subject: [OldTools] New directions - Thank you Andy!!! Well guys, the genie is out of the lamp!! I suppose its no surprise to anyone I have delved into cast pewter parts and decoration, done directly in and onto wood as people once did, but largely disappeared now. But there was one important aspect I hadn't figured out yet. Pewter bolsters and end caps. I was complaining about this one day, when up pops our own Andy Baughn. "Hey wait. When I was a kid my dad gave me a book on woodcraft and camping that covered that. Let me see if I can find it." And find it he did!! A few hours later he sent me a page scan of the old book. Couple of pictures and a few words threw the light on bright!! Today was my first test project. I didn't bother to take pictures as I went along. I didn't expect to be showing anyone the test subject. And truth to tell, if you had this in your hand there are a couple of un- saveable defects. But by and large, and for proof of concept, This totally rocks!! I took a favorite kitchen knife, one of a pair. (A weirdo pair looking like Donna Reed's 1962 kitchen, nobody would think sexy.) Yet they have blades of truly great steel. I don't know if this company made great blades all the time or the two I got in a box of kitchen junk at a yard sale were lucky specimens. But whatever, they are exceptional steel blades to my way of thinking. But the wood handles were very plain. Nice enough to grip, but no forged bolster or even an end cap at the blade end for sanitary purposes. Perfect test specimen!! I will do the whole photo tutorial later and hopefully with more detailed and decorative accents. But for now, it's tight and it's filling and not that bad for the first shot across the bow. Cast pewter bolster http://users.snowcrest.net/kitty/sgrandstaff/images/house/pewterbol ster.jpg Scott Grandstaff Box 409 Happy Camp, Ca 96039 http://www.snowcrest.net/kitty/sgrandstaff/ http://www.snowcrest.net/kitty/hpages/index.html ------- Date: Mon, 14 May 2012 15:06:20 +1000 From: Peter Robinson Subject: Re: [OldTools] New directions - Thank you Andy!!! Scott, that's lovely, well done. Now, I do have an issue with all this... photos are all well and good, but... what book is it? I must find one.... regards, Peter ------- From: James Thompson Subject: Re: [OldTools] New directions - Thank you Andy!!! To: scottgx~xxsnowcrest.net Oh! No! Not another slippery slope? Sooner or later, on this list, all mysteries will be revealed. Now I have yet one more really cool thing to learn, and I am afraid that if I stuff any more facts into my head, it will explode. Yet I have no choice but to learn how to do this. Miles to go before I sleep. Bring it on, Scottie! You lead, I'll follow. And Andy, please give us the name of the book. ------- Date: Mon, 14 May 2012 14:55:29 -0400 From: "Andy Baughn" Subject: RE: [OldTools] New directions - Thank you Andy!!! Glad to see it worked so well. I've had that book for most of my life and read it from time to time thinking someday I will build the wigwam, tipi, moccasins etc. Only thing I have done from it is tan a deer hide (worked great). Glad to see someone else was able to use it. One of the worst things people can do is not share knowledge with others. Bad Andy [later message] Oh, sorry. It was The Big Book of Indian Craft by William Ben Hunt. When I was a kid Grandpa had a tipi in his back yard. Me, my brother and my cousin would camp in it and pretend to be Indians. He gave me the book for my 8th birthday I think it was. Probably read it 500 times by now. ------- Date: Mon, 14 May 2012 12:07:03 -0700 From: scott grandstaff Subject: Re: [OldTools] New directions - Thank you Andy!!! > One of the worst things people can do is not share knowledge > with others. Man do you got that right!! All of that old "trade secret" crap hindered the advance of mankind like nothing else. Here is the page. Let me know if this works: http://users.snowcrest.net/kitty/sgrandstaff/images/house/Babbit.jpg yours Scott Scott Grandstaff Box 409 Happy Camp, Ca 96039 http://www.snowcrest.net/kitty/sgrandstaff/ http://www.snowcrest.net/kitty/hpages/index.html ------- NOTE TO FILE: That page includes instructions for making a skew knife from an industrial hacksaw blade, shaping a wood handle, and casting in place the metal portion of the handle using pewter or Babbit. Neat. ------- Date: Mon, 14 May 2012 15:12:11 -0400 From: Anthony Seo Subject: RE: [OldTools] New directions - Thank you Andy!!! Back when I was a young'un I probably had you beat on the number of reads. That is a great book for all kinds of projects. Ben Hunt used to write articles for Boy's Life, the Boy Scout magazine. His book on wood carving is great also. I got a replacement copy a few years ago just to have one around. The prices on the new ones are crazy high at least on Amazon but there are a bunch of used listings on there. There are also a number on Ebay right now. Just search for Ben Hunt Indian. Tony (who had a full outfit and headdress back in the Order Of The Arrow days...) Olde River Hard Goods http://www.oldetoolshop.com TSMusic on Facebook http://www.facebook.com/tonyseomusic ------- NOTE TO FILE: The following is a very well done video showing the steps and tips for producing a sand casting using his selected materials. ------- Core Sand & Match Plate foundry Pattern [shopbuilttools] Posted by: "Rod" granthamsx~xxwiktel.com rodney_grantham Date: Sat Jan 12, 2013 10:45 pm ((PST)) My latest project has been working on a rim chuck, which is like a diaphram with fingers. http://www.youtube.com/watch?v=MeYNLUNk0E4 shows a core box made from Trimplank which is a fraction of the cost of expanded pvc like Sintra, available from most home centers in their millwork department. It's another useful material for your shop. Your comments, questions and suggestions are welcome. Rod ------- Date: Tue, 9 Jun 2015 19:56:25 -0400 From: Claudio DeLorenzi Subject: [OldTools] Using old pewter for tool repair restoration Dear Fellow Galoots: I read a posting elsewhere from Scott Grandstaff on using pewter on a hand brace build. I came across an old router plane that was partially built, obviously craftsman made, in a long narrow pattern (similar to the E Preston router, which I have been looking for and not finding anywhere). If anyone has one for sale, please send me a message -- I am interested. Anyway, when I got all the old mud and crud off this thing, it looks to be bronze, and the two handles were actually Rosewood. The steel bolts on the handles were corroded so seriously that the hole in the rosewood knob has rotted significantly -- maybe a half inch all the way around, and the hole in the center mount is now far too large and some surgery is required to make this useful. I want to save the original rosewood knobs if I can- the outsides look nicely shape. The inside bottom of the knob has been carefully cut to fit over a central boss for the screw as well as two vertical brace walls, so I don't want to redo them if I can use the originals that the patternmaker made for this. I was going to just make a plug on my lathe and put it in there in a nice contrasting wood, but then I remembered Scott's posting on his brace build. I found it on his website (actually a different one, but about the same thing), and it looks like he just smelted some pewter in a tin can and made a pour through some aluminum foil. I thought it looked really good (as almost everything Sir Scott does at Happy Camp, a most impressive guy and an engaging writer to boot). At a flea market this weekend, I found a huge old pewter pot. Actually, I had to ask the pot guy if he had any pewter too ugly to sell, and he said something to his daughter in Russian who fished the thing out of a box in the back (apparently he was too embarrassed to display this thing with his good stuff, since it would drag down the quality of his wares). So for 10 bucks I have a ton of pewter, and I don't have to worry about destroying some precious artifact because this thing is really ugly and I will feel no guilt in destroying another man's work. The plan is to drill out the rosewood on my lathe out to a diameter of about 5/8 of an inch or so (to get to good wood), and then backfill with molten pewter, then polish and then drill and countersink for a brass screw. I thought the pewter next to rosewood would look awesome, especially with a polished slightly rounded brass screw in the middle of it. I think it will also be practical, since it will support the knobs well in all directions. Since this is an area I don't know anything about, I thought I would ask for help from fellow galoots. Any advice on using molten pewter would be greatly appreciated. Will the aluminum foil be enough of a dam, or do I need to use a heat sink next to it -- like wet clay or something? Will that much pewter cause the wood to just burn up -- so should I do several small pours and build it up slowly? Do I need to do anything to the previous layers to get the layers to bond together? I don't want to screw this up, so I need some advice. I'd be interested in hearing from anyone with experience in the casting arts. I did try to email Scott, but I think the electrons got lost on the way to Happy Camp, so I did not hear back from him... Claudio AKA DrDee Waterloo, Ontario Canada ------- Date: Wed, 10 Jun 2015 20:03:57 -0400 From: Charlie Driggs Subject: Re: [OldTools] Using old pewter for tool repair restoration Hi Claudio Go for it. Jim Thompson and Scott Grandstaff combined to convince me to tackle casting pewter for tool repairs or upgrades a fair while back, and IIRC three out of four jobs I tackled came out just fine. I had major difficulty replacing missing pewter rings on the grip of an otherwise nice Stanley brace, which I traced to the molten pewter cooling in the channels on the grip before it could completely fill the circumferential grooves. That brace still hangs from the ceiling joists and someday I'll get back to figuring out how to do that one successfully, but the repair you are proposing seems to be one I'd expect to go quite nicely in a single pour as long as you have enough material in the melting pot. I think it is highly unlikely the rosewood will be set alight by pewter that is just a bit warmer than necessary, as the melting point of the pewter I have used (also from pewter cups, pots, bent college mugs, etc.) is well below the ignition temperature of solid wood. I used masking tape to create and close up pour channels (as close as we will get to being sprues), and I expect you could do the same. Less thermal mass in whatever you do to guide or retain the molten pewter is better, as pewter is poor at holding its heat compared to steel or copper, and you don't want to be pre-heating things in the oven when wood parts are involved. If you did use dense metal or other substances as heat sinks, or something that rapidly transfer and are good at retaining heat, the pewter just might solidify before you saw a fully developed pour. Scott is far more skilled at this than I am, but casting small pewter items was a much easier experience for me than pouring lead and tin into foundry-style sand molds way back in junior high school shop class over a half century ago, and less dangerous too. I do remember Mill Rat telling me to use something that would act as a release agent on surfaces on which I did not want to see pewter penetrating and sticking, and it has been so long now that I don't remember if I used wax, petroleum jelly, or something else. As I recall, I discovered it is also possible to have the molten pewter too hot, reduce the chance for a successful pour -- as indicated by a skim of purplish-yellow material on a majority of the surface of the molten pewter. I initially used a propane torch to heat the cheap little stove pot used as a crucible, and subsequently found a very nice two burner hot plate (new for less than $30 US) that worked more controllably. I suggest that you make a test pour or two in other materials that are expendable before trying the very pour that drove you to ask these questions. Charlie Driggs ------- ------------------------------------------------------------------ This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------