Book - Appendix D - Resources
The Casting and Mold Making FAQ from Raven's Forge Miniatures
"Bo" Mathews from Raven's Forge Miniatures has kindly allowed me to replicate his FAQ on mold making and casting that is hosted at his site - http://www.ravensforgeminiatures.com/. This FAQ is a rather helpful document to anyone interested in getting started in making molds and casting things from white metals. Thanks Bo for letting us give it another home here.
Researched and Written by: David R. "Bo" Mathews (This email address is being protected from spambots. You need JavaScript enabled to view it.)
CHANGES FROM V. 2.01.01
1.) Section 2.4 Latex Rubber written
2.) Added section 6.3 Plaster as a Mold Making Material
3.) Section 8.14 Pewter revised to make easier to read/less confusing
4.) Added section 8.3 Plaster and Plaster Type Materials
5.) Added the following firms to dealer list: Micro-Mark; Alumilite Corporation; Dow Corning Corporation; Conley Casting Supply Corporation; Castings; Contenti; Alumilite; Lee Precision; Synair Corporation; Ortho Cast, Inc.
6.) Section 10.0 Where Can I get? has been reorganized (see Table of Contents for new sections)
TABLE OF CONTENTS
1.0 PURPOSE OF FAQ
2.0 TYPES OF MOLDMAKING MATERIALS
2.1 What Do You Mean By "Vulcanized" And "Vulcanizing"?
2.2 How Does Heat Vulcanization Work?
2.3 What Is "Room Temperature Vulcanizing Rubber"?
2.4 What is Latex Rubber?
3.0 MODELS FOR THE MOLDMAKING PROCESS
3.1 What Type Of Materials Are The Original Figures Used To Make The Molds Sculpted From?
3.11 How well do the two part epoxy masters hold up to the heat vulcanization process?
3.2 Since There Is No Heat Used In The RTV and Latex Moldmaking Processes, What Type Of Material Can I Use When Sculpting Figures?
4.0 PROCESS FOR MAKING AN RTV RUBBER MOLD
4.1 Materials And Equipment Needed For An RTV Mold
4.2 How Do I Make A Two Part Mold?
4.3 The One Part Mold
5.0 PROCESS FOR HEAT VULCANIZED RUBBER MOLDS
5.1 Materials Needed
5.2 How To Make A Heat Vulcanized Rubber Mold
6.0 LATEX MOLDS
6.1 Materials Needed
6.2 How To Make A Latex Mold
6.3 Plaster as a Mold Making Material
7.0 GATES AND VENTS
8.0 CASTING
8.1 White Metal
8.11 Alloys
8.12 Zinc And Alloys
8.13 Tin And Alloys
8.14 Pewter
8.15 Lead And Alloys
8.15.1 Lead poisoning OR "Can I get lead poisoning by casting using lead?"
8.2 What about resin?
8.3 Plaster and Plaster Type Materials
8.31 Silicosis
9.0 WHAT ELSE CAN YOU TELL ME?
9.1 What Are Some Of The Pros And Cons Of Heat Vulcanized Rubber, RTV Rubber And Latex Rubber Molds?
9.2 What About Other Hazards? SAFETY THOUGHTS! READ THIS!
9.3 Is Casting Your Own Figures Really Fun?
10.0 WHERE CAN I GET..............................................?????????
10.1 Heat Vulcanized Rubber And Related Equipment
10.2 RTV
10.3 Resins
10.4 Metal and Accesories
10.5 Sculpting Tools And Putty
10.6 Pre-Made Molds And Accesories
10.7 General Information
11.0 GLOSSARY12.0 CONCLUDING THOUGHTS.
1.0 PURPOSE OF FAQ
This FAQ is a work in progress, to share what I have learned and continue to learn about RTV, Latex and Heat Vulcanized rubber molding techniques, and about casting from these molds using white metals, resins, and plaster. I am continously working on it, in order to update and expand the information presented herein. If anyone has any questions, please e-mail me at the address below. Questions about moldmaking and casting and requests for clarification and/or additional information are welcome, as they let me know what I need to work on for new additions, ultimately, make this FAQ better.
2.0 TYPES OF MOLDMAKING MATERIALS
There are three types of materials to consider when one is casting using white metal alloys, resin compounds, or plaster: heat vulcanizing rubber, room temperature vulcanizing rubber (RTV), and latex rubber.
2.1 What Do You Mean By "Vulcanized" And "Vulcanizing"?
The vulcanization of rubber was discovered by Charles Good year in 1839. This process hardens and strengthens the rubber drastically, as well as improving its elasticity and flexibility. Through vulcanization, rubber gains the ability to withstand the heat from molten white metal.
There are two methods to vulcanize rubber. The first involves heat and sulfur compounds in the vulcanization process, and the second uses a chemical reaction caused by the addition of a catalyst to liquid rubber.
2.2 How Does Heat Vulcanization Work?
Vulcanization is a process of heating rubber until it becomes a viscous mass, and then allowing it to cool down. In vulcanized mold making, this heating is done ahile the mold is under a great deal of pressure. This pressure serves two purposes: it forces the viscous mass of rubber into the spaces around the model, and also keeps the rubber from expanding and becoming too porous (which rubber can and will do when heated). There are several types of heat vulcanization, using heat, or a combination of both heat and sulfur compounds. The heat vulcanized molds I will discuss use only heat.
2.3 What Is "Room Temperature Vulcanizing Rubber"?
Room Temperature Vulcanizing rubber (RTV rubber) is a type of rubber which vulcanizes chemically, without the addition of heat. RTV is found in either one part or two part (rubber and catalyst) compounds
2.4 What is Latex Rubber?
Latex rubber is a liquid type of rubber made from the gum/sap of the hevea tree and guayule and milkweed plants. It is highly unstable, and begins to decompose in several hours after collection. However, the addition of 0.6% to 1% ammonia acts to prevent decompositon or coagulation.
When exposed to air, preserved latex liquid forms a thin skin over the object it is used to coat. The addition of successive coatings bind together to form a thicker skin. The latex will stick easily to itself even after it has set, although a light dusting of talcum powder will usually prevent this. It does not withstand heat very well, but can be used to make molds to be used with plaster or two part resin.
3.0 MODELS FOR THE MOLDMAKING PROCESS
3.1 What Type Of Materials Are The Original Figures Used To Make The Molds Sculpted From?
The master model for a heat vulcanized rubber mold must be made of a material that can withstand heat (335 ) and pressure (several hundred pounds of pressure). The most common materials used to produce these models are metal and two part green epoxy putty.
3.11 How well do the two part epoxy masters hold up to the heat vulcanization process?
Epoxy models survive the process, but usually grow brittle due to the heat and pressure. Occasionally, after the mold is vulcanized, while the models are being removed from the mold, they will fracture or break (especially small parts). This breakage or fracturing in no way harms the mold. It harms only the master model's ability to be used to make another mold. However, since the mold has already been produced at this point, a new master may be easily cast from it.
3.2 Since There Is No Heat Used In The RTV and Latex Moldmaking Processes, What Type Of Material Can I Use When Sculpting Figures?
For RTV rubber, the master may be of any material, since it does not need to be able to withstand heat or pressure. Metal, epoxy putty, jeweler's wax, or almost any type of material can be used to create the master when RTV or latex is used as the mold material.
4.0 PROCESS FOR MAKING AN RTV RUBBER MOLD
There are two methods for producing an RTV mold: two part mold and the solid mold. The two part mold is the one used by most amateur mold makers, and requires longer to complete than the solid mold.
4.1 Materials And Equipment Needed For An RTV Mold
RTV rubber compound and activator bowl, measuring cup, stirrers to mix RTV
plasticene
lego blocks, plastic card or material to make a mold box
mold locknuts or cylindrical object to make holes in clay with
mold release
model
vacuum table or vibrating table (to get air out of RTV after mixing and after pouring in mold)
4.2 How Do I Make A Two Part Mold?
In the two part mold process, the model is embedded in modeling clay or similar substance to about 1/2 its thickness or depth, and mold locks added. Mold locks align the two mold halves together. Mold locks can be made by poking holes into the clay the model is mounted in (the filling of the holes by the RTV will create pegs, and the pouring of the second half of the mold will create holes for the pegs), or by use of brass or steel mold locknuts. The exposed model, clay and mold form are then coated with a substance to keep the RTV from sticking firmly to them. Vaseline dissolved in naphtha (1:9 Vaseline to naphtha ratio) is often used as a release agent. However, caution should be taken with it, as it can be unstable and EXTREMELY flammable. There are several good spray agents on the market. Just shake them up and spray (like spray paint). Dishwashing soap mixed 1:9 with water and brushed on is recommended by the Dow Corning Chemists (thanks to Reaper Ed for that bit of info), and is cheaper and safer than any of the other agents.
Half the RTV compound is then thoroughly mixed, de-aired using a vacuum table, and poured gently into the mold box (this can be made from plastic card, lego or other materials) at the lowest point, until the highest point of the model is covered with the RTV compound to a depth of at least 1/4". After being de-aired on a vacuum or vibration table the mold is then set aside and allowed to cure. If you do not own a vacuum table (few do - they are fairly expensive and delicate), you can use cheap brushes to brush several thin coats of the RTV compound over the model, working it into the cracks and crevices, and then pour the mold full. Also, the mold can be tapped firmly but gently after being poured, to shake the air bubbles to the top.
When the mold has cured, the mold is turned over and the clay cleaned from the model and mold half. The model, cured RTV, and mold form are then coated with a release agent. The second half of the RTV compound is then mixed, poured into the mold form, and de-aired to create the second half of the mold. When the compound cures, the mold is pulled apart carefully, the model removed and everything fully cleaned. Next, a sprue (or pouring channel) is cut, and the first figure cast. Then, any needed gates and vents are cut.
4.3 The One Part Mold
The solid mold process is somewhat different. The model is mounted on a rod of some sort (which usually serves to form the pouring gate), and placed standing upright in the mold form, which is custom made per model and allows for at least 1/4" thickness of the mold on all sides. The full amount of RTV compound is mixed, de-aired and poured into the mold. The mold is then placed on the vacuum table, and de-aired. After the mold has cured, the mold form is removed, and the mold carefully cut apart. This is a dangerous procedure, because the knife used to cut the mold can easily slip and cut the mold cutter, or can bounce up and imbed itself into the mold maker. After being cut apart, the first figure is cast, and then the gates are enlarged (if necessary) and vents are cut.
5.0 PROCESS FOR HEAT VULCANIZED RUBBER MOLDS
5.1 Materials Needed
Heat vulcanization machine
heat vulcanizing rubber (flat sheets)
heat vulcanizing mold frames
mold locknuts
model
spray release
rubber solvent
mold knife
sprue former
5.2 How To Make A Heat Vulcanized Rubber Mold
Heat Vulcanized Molds are made in quite a different process. The model is attached to a sprue former. The mold frame (a box with four sides, and a removable top and bottom) is placed on its bottom plate, the mold is filled with rubber sheets (cleaned with rubber solvent) roughly halfway and the model and locknuts are placed into the mold. A release agent is used, as with an RTV mold, and can be a spray agent, or Talc, which is dusted on (thanks again to Reaper Ed). After the release agent is used, the mold is filled to the top with rubber. The rubber sheets usually are cut into to allow some space for the model. The top plate is placed on the mold and the entire form is placed into the pre-heated vulcanizer. Pressure is applied gradually throughout the first 5-10 minutes, and then the mold is allowed to "cook" a certain amount of time, according to the mold thickness.
After the "cooking" is done, the mold frame is carefully removed from the vulcanizer, opened up and allowed to cool. When cool, the mold is opened up. The release agent usually negates the need for cutting the mold open, but occasionally some cutting must be done to fully release the mold halves from one another. The first figure is cast, and vents are cut into the mold as needed.
6.0 LATEX MOLDS
Latex is a type of rubber used to make molds for use with casting mediums requiring no heat, such as plaster or two part resins. They CANNOT be used for any type of metal casting. The mold life for latex molds is usually fairly short, especially if they are used for anything with a severe undercut in the mold. They do not lend themselves well to two part molds, instead being used for "skin molds" with one side open to pour the casting materials into and forming a flat surface for the base. They are used most often to model scenery pieces cast in plaster or resin with only three sides.
6.1 Materials Needed
Latex mold compound
Brush(es)
model
clay
box material
mold release
6.2 How To Make A Latex Mold
Imbed the base of your model into the clay. Build a box around your model. Spray on mold release. Using the brush, brush the latex carefully onto the model, being sure to get into all of the cracks and crevices. The first coat should be fairly light. Continue coating the model until the latex is 1/8 to 1/4 inch thick on all points of the model. Allow the latex to cure as per instructions. Peel the mold off of the model. The mold can also be made more stable with the addition of a plaster "box" around the mold. When making a plaster mold around the latex mold, coat the entire inside of the box the latex mold is in and the latex mold with release, and pour a thin (1/4 to 1/2 inch) shell of plaster over the latex. This thin shell of plaster will allow for more stability of the latex mold, and will also allow for the latex mold to be removed from the plaster mold when de-molding the casting made in the latex mold. Be aware that the plaster box can be extremely delicate however, and is easily broken. (special thanks to Bill Armintrout and Binhan Lin, who use this technique, and were kind enough to tell me all about it and put up with all of my questions!.) The latex mold can be strengthened by adding hardware cloth (fine wire mesh screen) or heavy gauze to the mold between the latex coats. (thanks to Al Fisher)
6.3 Plaster as a Mold Making Material
Someone has e-mailed me to ask the following: I was wondering if "Plaster of Paris" (the plaster that anyone can get from any hardware store) is able to withstand the heat of a low temp. metal like lead or pewter. I was thinking of making a mold out of it and then using lead to make the copies. Will it work (or will it just melt the plaster)?
The problem with using plaster to make a mold is that plaster is a hard brittle substance. It could be used as a mold with latex or RTV rubber being cast into it, but not a hard substance such as white metal - the mold would have no give, and so would not flex. The flex is needed to allow the removal of the metal figure (RTV and Latex have enough give and flex to pulled out of a plaster mold). Also, plaster is made with a great deal of water, and if not fully dry, the moisture would cause the hot metal to spew out the gate with explosive force, causing an extremely dangerous hazard.
It is for this reason that I can not see using plaster as a mold making substance, except for casting parts in RTV or latex rubber. Please note NOT to wash any implement used in plaster in a sink or wash the plaster down any drains - it will stop them up PERMANENTLY. Allow plaster to dry, it will crumble easily, and can then be re-used or disposed of. (see section 8.3 Plaster and Plaster Type Materials)
7.0 GATES AND VENTS
Gates are the channels that carry molten metal to the mold cavity, while vents are the channels that carry hot gases from the mold cavity. They are cut as needed after the mold is made. Usually, they are found in the form of triangular shaped channels cut into the mold rubber. Gates carry the molten metal to the mold cavity, and are usually made when the mold is vulcanized, through use of a model gate added to the model. Gates may also be added after the mold is vulcanized. Vents are cut after the mold has been cast a few times. They are cut from areas that are not filling with molten metal, indicating an area that is trapping hot gases and not letting the cavity fill up. Vents are cut in the same way as gates, but are cut from the mold cavity to the outside edge of the mold, usually to the same side of the as the gates ( especially in rectangular home casting molds), to keep the molten metal from flowing out of the sides or bottom of the mold, and causing problems.
8.0 CASTING
8.1 White Metal or What types of material can you use to cast figures with these molds?
White metal (i.e. lead, lead alloys, Britannia metal, pewter, and other low melting point, non-ferrous metals - anything that melts under 800 degrees) may be used, as well as two part or heat melting resin compounds. White metal casting can be done with both RTV or heat vulcanized rubber molds, but NOT with latex molds.
Heat vulcanized rubber molds will produce more quality castings per mold. Unfortunately, there are so many variables that can affect the quality of casting that it is hard to give a percentage of castings one could expect to get from heat vulcanized rubber molds over RTV molds. On the average, it should be 75% more. However, because of variables, it could be as low as 50%, and as high as 175%.
8.11 Alloys
Alloys are combinations of two or more metals made to improve the qualities of the base metal. The primary base metals for casting are Zinc, Tin, and Lead. The metals used in alloys include Aluminum, Antimony, Cadmium, and Copper.
8.12 Zinc and alloys
Zinc (Zn) is a high temp white metal, melting at 788 degrees in its pure state. Zinc and its alloys are not usually the first choice of either the home or commercial caster. They may be composed of 88-96 % Zinc, 4-11 % Aluminum, and 1-3 % Copper, depending on the type of alloy. They have fair to good fluidity when molten. The casting range is 735 - 875 degrees, which is a bit high for the rubber molds, and can lead to faster mold burn out. Zinc alloys are quite brittle, not easily bent, and are only fair in their ability to take small detail.
8.13 Tin alloys
Tin (Sn) is a white metal with a relatively low melting point of 450 degrees. It is light weight in comparison to lead, has a high fluidity when molten, and is hard without being too brittle. Tin alloys may be composed of 90-92 % Tin , 2-8 % Antimony , .25 % Copper, 2 % Cadmium, and 4-6 % lead, depending on the alloy. The casting range is 515 - 625 degrees, which is considerably lower than zinc, and comparable to lead. It has good strength, takes detail well, and has less chance to burn molds.
8.14 Pewter
Originally, pewter was an alloy made from tin and lead, with other metals added.
These days, pewter is defined by the American Society for Testing and Materials (ASTM), as "a lead free alloy of high tin composition". It consists of 92 % Tin, 6-7 % Antimony, and 1-2 % Copper. This alloy is known as "Certified American Pewter."
8.15 Lead alloys
Lead (Pb) is the original metal for casters, with a melting point of 621 degrees. It is quite heavy in ratio of weight to volume, has little strength in its pure form, and takes detail poorly. It does have the ability to alloy well, however. Lead alloys contain 62-95 % Lead, 1-35 % Tin, and 3-13 % Antimony. Lead alloys have a casting range of 510 - 700 degrees, with fair to very good fluidity. They take detail moderately well, along the lines of Zinc alloys. The main concern of lead is toxicity over time. Lead fumes, dust and the ingestion of lead are all methods of lead poisoning (see 8.15.1).
8.15.1 lead poisoning OR "Can I get lead poisoning by casting using lead?"
Molten lead (and any alloy containing lead) will give off lead vapor, which can be dangerous if you are exposed to high levels over a period of time. However, non-lead alloys are now available through several of the metals suppliers. A filter mask rated for metal vapor is a must when casting, even with non-lead alloys, as is a well ventilated area to set up your equipment. Also, filings, dust, and small cuttings from lead miniatures can be ingested, which can lead to lead poisoning.
8.2 What about resin?
There are several two part and heatable resins available that will work in molds. Both types should work fine in these types of molds. I am looking into the various types of resin/plastic that can be used.
8.3 Plaster And Plaster Type Materials
Plaster of Paris may be used in a mold as a casting medium for making scenery and such. It can also be used as a backing for a latex skin mold, to give the latex mold strength. It is not recommended for use in casting figures.
Plaster is mixed in a plastic or rubber bowl with water to a slurry state (slightly thicker than pancake batter), poured into the mold, and then allowed to harden/dry. Note that drying plaster is exothermic, meaning it generates heat as it sets and dries. Gently pick up the mold and tap it against the surface it is sitting on just after you pour the plaster. This will cause air bubbles to rise out of the plaster to the top of the mold.
Cleanup of plaster is quite easy. Allow the plaster to dry in the bowl, then just flex the bowl and most of the leftover will come out in chips. Please note NOT to wash any implement used in plaster in a sink or wash the plaster down any drains - it will stop them up PERMANENTLY. Allow plaster to dry, it will crumble easily, and can then be re-used or disposed of. Use the chips as filler for your next pieces. Also, you can use reuse old plaster (ground up into dust) mixed with new plaster at a rate of 1 part old to 10 parts new (1:10 ratio old:new).
8.31 Silicosis
Silicosis is a lung disease caused by breathing air filled with small silica particles over an extended period of time. Plaster contains finely ground silica, and long term exposure can cause silicosis. When working with plaster, wear a dust mask and try not to stir it hard enough to cause dust.
9.0 WHAT ELSE CAN YOU TELL ME?
Lots, just keep reading.....................and asking! This section is for questions and thoughts that need to be addressed, but do not easily fit into one of the categories in the FAQ. They may eventually form new sections, but at this time, are not ready to be reclassified into new sections.
9.1 What Are Some Of The Pros And Cons Of Heat Vulcanized Rubber, RTV Rubber And Latex Rubber Molds?
Heat vulcanized rubber is stronger, harder, more elastic, more flexible and more durable than RTV rubber. It will give more quality castings per mold over RTV rubber. Heat vulcanized molds do require specialized equipment, which uses both high temperatures and pressure and can be dangerous if strict attention is not paid during its use. The rubber can be burned if heated too high or for too long, but if not heated high enough or long enough can be returned to the vulcanizer for proper heat treatment.
RTV rubber requires that the proper amount of catalyst be mixed into the uncured rubber. It must also be placed on a vacuum table or vibration table to remove any air trapped within it before being poured into the mold form. These are expensive pieces of equipment, and are really a must for making RTV molds. Without proper de-airing of the RTV, air bubbles can form around the model, causing imperfections in the casting, or weaken the mold, ruining it.
9.2 What About Other Hazards? SAFETY THOUGHTS! READ THIS!
Hot metal splatters when it is spilled, and can burn through flesh and clothing. Also, the mold used with the white metals MUST BE ABSOLUTELY DRY!! Any moisture in the mold cavity will cause the HOT METAL to come spewing out the gate with explosive force, causing an extremely dangerous hazard. Make sure ALL molds are dry - heat vulcanized molds may be damp from the air, while RTV molds that are not fully cured will have residual moisturewithin them.
Resin can be a skin, eye and respiratory irritant.
Plaster, while an inert substance, is finely ground, and an irritant to lungs (see 8.31 Silicosis). It must also be allowed to fully dry before excess is disposed of. Wet plaster poured down sink drains can easily stop them up.
The mold separator spray, while not necessarily toxic, is an irritant to both eyes and lungs, and probably flammable, depending on the type of propellant used.
Equipment always has the potential to be dangerous. The equipment for RTV or heat vulcanized molds is no different. The RTV equipment is delicate and must be properly maintained. The equipment used for heat vulcanized rubber is not delicate, but it is heavy. It also has high temperature surfaces that can produce very bad burns.
Always remeber that moldmaking and casting, while fun and easy (once you get the hang of it!!) is an ADULT endeavor. One should always wear latex/plastic gloves when handling RTV or resin and heavy industrial heat resistant gloves when casting with metal. And - DON'T FORGET EYE PROTECTION - your sight is extremely valuable, and much too precious to risk!
9.3 Is Casting Your Own Figures Really Fun?
Casting you own figure is quite rewarding. In addition to sculpting your own figures, you can make pieces to modify commercial figures, and make those odd little units that every period has but commercial companies can't or won't bother with.
10.0 WHERE CAN I GET..............................................?????????
The following list includes many companies that carry equipment and supplies. They are organizewd into sections, so as to make it easier to find the companies carrying materials you are interested in. Several companies are listed more than once. The first listing of a company will include full address/phone number/etc., while the second will include only the name of the company and the previous section it is listed in.
10.1 Heat Vulcanized Rubber And Related Equipment
Conley Casting Supply Corporation
124 Maple Street / Warwick, RI 02888
(401) 785 9500 / (800) 445 7900 / (401) 781 9420 FAX
Jewelry supply company. Carry equipment and supplies for figure sculpting and casting.
URL: http://www.vpm.com/conquest
Contenti
123 Stewart Street / Providence, RI 02903
(800) 343 3364
Romanoff Rubber Co., Inc.
9 DeForest Street / Amityville, NY 11701-2805
(516) 842 2400 / (800) 221 7448 (order department)
Romanoff sells a great deal of equipment for making molds. They offer RTV to make gravity molds (it's fairly expensive), commercial equipment and material to make spincast molds, commercial spincasting equipment, lead/ lead alloy/ pewter melting pots, sculpting tools, etc.
Tekcast Industries, Inc.
12 Potter Ave. / New Rochelle, NY 10802
(914) 576 0222
Somewhere in all of the information you get there is a catalog. A small one. I am sure I saw one somewhere. Actually, they send several brochures on their products. Each one is packed full of information that is very useful to someone interested in moldmaking and casting. Emphasis on their commercial equipment for spincasting.
10.2 RTV
The Castolite Co.
P.O. Box 391 / Woodstock, IL 60098
Large catalog full of information. B/W photos of sample ways to use the products. They offer RTV, moldmaking materials, and several types of casting resins/plastics.
Dow Corning Corporation
Midland, MI 48686-0994
Produce a number of RTV rubber compounds. Request their RTV moldmaking package. It is full of information.
Fiberlay Inc.
2419 NW Market St / Seattle, WA 98107
1-800-942-0660 Order Line / 1-206-782-0660 Technical Support Line
Carry primarily bonding epoxy for the surfboard and boating industry, they also have a (small) section carrying RTV and latex rubber, and casting epoxy resin. Also carry two part expanding foam and equipment for mixing the resins, rubber and foam.
K. R. Anderson Co., Inc.
2800 Bowers Ave. / Santa Clara, CA 95051
(408) 727 2800
Epoxies and RTV's
Rio Grande (10.1)
Romanoff Rubber Co., Inc. (10.1)
Tekcast Industries, Inc. (10.1)
Vagabond Corporation,
P.O. Box 39 / Warner Springs, CA 92086
(619) 782-3136 / (619) 782-3138 FAX
Vagabond sells Model-Cast Casting Resins and silicone rubber (RTV).
(thanks to Al who sent me this!)
10.3 Resins
Alumilite Corporation (10. 2)
The Castolite Co. (10.2)
Fiberlay Inc. (10.2)
K. R. Anderson Co., Inc. (10.2)
Synair Corporation (10.2)
Vagabond Corporation (10.2)
Alpha Jewelry Supply, Inc.
Box 2133 / Bremerton, WA 98310
Jeweler's supply house. Files, carving tools, etc.
10.4 Metal and Accesories
Belmont Metals
320 Belmont Avenue / Brooklyn, NY 11207
Metal supplier
Lee Precision
4275 Highway U / Hartford, WI 53027
(414) 673 3075 / (414) 673 9273 FAX
Firearms reloading component manufacturer. What is useful here are the white metal electric furnaces they sell. All have thermostats, plug into the wall and are under $100. The last catalog I received had a list of factory seconds for sale, and included two furnaces.
10.5 Sculpting Tools And Putty
Micro-Mark
340 Snyder Ave.,Berkeley / Heights, N.J. 07922-1595
General info: 1-(908)464-8764 9a.m. to 5 p.m. weekdays only. / Fax: 1-908-665-9383
The small tool specialists, have tons of tools and supplies for modelers available.
Raven's Forge Casting Company
904 Edgewood Drive / Sheffield, AL 35660
A miniatures company, but also offer custom heat vulcanized rubber gravity molds from customer's original models, and custom spincasting. Also carry two part green epoxy in original strip form (not "tootsie roll" packaging, but strip form!) for sculptors.
10.6 Pre-Made Molds And Accesories
Castings
Orcas Island / PO Box 298 / Eastsound, WA 98245 0298
Carry already made molds and equipment for casting with these molds or others.
The Dunken Co., Inc.
511 Main Street / P.O. Box 95 / Calvert, TX 77837
(409) 364 2020 / (409) 364 2752
Dunken sells already made molds, both metal and rubber (Prince August brand too), as well as the accessories to go with them.
10.7 General Information / Not Yet Classified
Castcraft
P.O. Box 17000 / Memphis TN 38187-0000
Brochures trying to sell books full of info on how to use and how/where to get moldmaking and casting equipment and materials.
Douglas Walsh
Vacuum Form
272 Morganhill Dr. / Lake Orion, MI 48360
Mr. Walsh sells a vacuum pump that can also be used as a compressor. He also sells plans for building your own vacu-form machine, oven kits, and several other items. (thanks to T. Martin who sent me this)
11.0 GLOSSARY
Alloy - combination of two or more disimiliar metals made to improve one metal, to change its characteristics, or to lower its cost
Cavity - negative impression of a model that has been cured (vulcanized) into a rubber mold. Molten metal or resin poured into the mold cavity will produce a casting / reproduction of the original model
Fluidity - Ease of pour for molten metals
Gates - Channels cut in a mold that carry molten metal to the mold cavity
Model - anything used to cure a cavity in a rubber mold
RTV - a liquid silicone rubber which cures at room temperature by addition of a catalyst
Vents - Channels cut in a mold to carry hot gases away from mold cavities
Vulcanization - The process of treating crude rubber with heat and/or chemicals to decrease plasticity, tackiness and sensitivity to high temperatures and give it useful properties such as strength, hardness, stability, and elasticity
12. 0 CONCLUDING THOUGHTS.
Thanks to all who have sent info to me. I try to credit everyone who helps with this, but sometimes inadvertantly miss someone. If I have missed you, I apologize, and please let me know.
I must emphasis that this is strictly an ADULT endeavor. I recommend being at least 16 if you are not working under parental supervision.
Again, if anyone has any questions, please e-mail me at the address below. The questions I get are always answered, although it may take me sometime to do so.
This FAQ is officially maintained by Britt Klein at the kewlaid.highfiber.com FTP site. If anyone wishes to create a link to this site from their page, or wishes to post this FAQ on their page, please contact me about doing so. Also, please contact me with information about links or postings (so that I can keep up with them, and send updated copies!).
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Appendix D - Resources
Listed below are websites, books and other items of interest to the mold making, casting, plating hobbyist. Do you notice something missing? Let me know of a resource you find valuable and I will share it with the rest of us.
Web Sites of Interest
http://www.backyardengineer.com/ (Back Yard Engineer) - Kevin Regan's site with some really cool information on injection molding machines that he builds in his garage. Kevin even offers parts for his designs.
http://www.computersculpture.com - Andrew Werby's site with information on creating masters.
http://www.unitedartworks.com - FAQs from the alt.sculpture news group can be found here. These contain some info on molding and casting
http://www.backyardmetalcasting.com - Lionel Oliver's foundry page. Home of the flowerpot crucible furnace.
http://www.ray-vin.com/frtech.htm- Ray Brandes' Foundry site. Contains excellent examples and a very nice air driven vibrator (Excellent for shaking bubbles from plaster castings!) You can get the plans or purchase it.
http://www.lindsaybks.com - Lindsay Publications - Highest quality books, new and old, for experimenters, inventors, tinkerers, mad scientists, and a very few normal people..
http://www.dansworkshop.com - Mr. Daniel Hartman has a lot of great information on his site about casting and an excellent page on modifying and improving Gingery's Lil' Berth. Check it out, you won't be disappointed!
- You have reached the James Rogers Sculpture Studio web site. We are a premier producer of grade "A" sculpts for the toy and collectable industries. Please look around to get a better idea of our work, and how we go about it. When going to this site and are looking at the mold making process, delete part of the url so it reads http://www.jamesrogersstudio.com/molds/ you will get a bit more detail on how they do it. Nice site.
http://www.SCULPT.com - We are the largest distributor of all thing sculptural, including but not limited to molding compounds, casting compounds, finishing tools & patinas. We represent Smooth-On, Polytek, Alumilite, Dow, Silicone's Inc, USG, & US Bronze, just to name a few. We also stock a line of vacuum chambers as well as all your other molding accessories. As a part of our service we have a free technical support department at your disposal , plus online tutorials.
http://metalshop.homestead.com/ - Dave Drescher's site has his dealings with a number of projects, including lost foam casting, lock repair a boat plaque and much much more. Take a gander at this site and it should help you get some ideas.
http://www.freemansupply.com/ - This site will be of help to some of you. They have over two hours of instructional video online for you to view on mold making and other topics.
http://ForgeGallery.EllisCustomKnifeworks.com - Darren Ellis' site on furnace/forge building. This site has lots of great pictures. Check it out.
http://home.c2i.net/metaphor - David Reid's site has too much stuff to list it all here. There are articals on casting, wax and loads more. A very nice site. Have a look, as I am sure there is something there that will interest you.
Books
These are some of the books that I have got and found them helpful and interesting. The majority of them I have ordered from Lindsay Books. If you have not been to their site, I would highly recommend you check them out.
The Charcoal Foundry - (From the back of the book.)
Working in metal is one of the oldest and most fascinating of the crafts. A source for castings of parts, members and working stock is difficult to find, but you can easily produce your own at home. There are no great technical obstacles to overcome and costs are surprisingly low. There is no need to go to a custom foundry or machine shop for help. The simple manuals in the "Metal Shop From Scrap" series will show you how to build and use the equipment you need to produce your own castings, parts and machines.
The main ingredient is these projects is scrap aluminum and pot metal. The only tools you need to start are ordinary home shop hand tools, many of which are probably already in your possession. Much of the remainder is found as salvage or cast-off and little expense need be involved.
Being in the lower melting range of the metals, aluminum and pot metal are delightfully easy to work with. If you are one who has attempted to weld or solder aluminum you may feel that you would encounter the same frustrations in an attempt to produce a casting, but exactly opposite is true. It melts easily, quickly and clean, it is extremely fluid and there are no deep secrets involved in handling it. Castings shake out clean and bright and you very first one is most likely to be a success.
The charcoal foundry is extremely simple to build and operate and the initial cost is so low that it can be in the reach of nearly anyone. The fundamentals of pattern-making and molding are quite easily understood and mastered. You can make great strides with simple tools and materials that are usually on hand in most home shops.
Once you have built the charcoal foundry and the lathe there is little beyond your reach by way of shop equipment. You can build as large or small as you wish and you are your own parts supply company. If you already have some machine shop equipment you will find that adding a foundry to your shop greatly expands your capacity. Being able to produce your own castings of parts for accessories and equipment is a great advantage. Design your own, make a copy or follow a plan. It's easy when you can produce your own castings. It's easy, low cost and great fun. See if casting won't open a whole new world of shop experience for you.
The Metal Lathe - (From The Back Of The Book)
Having been descibed as "the only machine that can duplicate itself or any other machine in the shop", the metal lathe is the most versatile and desirable of all metal working machine tools. It is certainly among the most expensive pieces of equipment, but there is no need to do without one in your shop because here is a lathe that can not only duplicate itself, but it can produce its own original parts from home made castings and stock materials. A fascinating project from its simple wooden patterns through finished castings and finally a complete machine. You will master many basic skills as you progress.
The basic machine described in this manual has a compound slide rest, belt powered lead screw, split nut carriage feed, adjustable gibs in sliding members and adjustable tailstock set over for taper turning. With its 7" swing and between centers capacity of 12", it provides the foundation for the complete home metal working shop. A machine you'll enjoy building and one you'll be as proud to own as any you might buy.
A later manual in the series will show you how to add change gears, a four jaw chuck, center steady rest and other very desirable and helpful accessories to your equipment. All you need to begin is the charcoal foundry and basic hand tools. The only power tool used to construct the original lathe seen in these photos was a 3/8" electric hand drill. All of the parts are machined on the lathe itself as it evolves. There is never a need to look for outside custom machine work.
How to make patterns and how to mold them, how to use basic hand tools to prepare the castings for final finishing, and how to set them up for accurate machining on the developing lathe are all covered. The original lathe was used to machine a complete set of parts for a second identical machine, and so it not only duplicated itself but actually originated itself to a large extent. A delightful metal working project that provides a very thorough educational and a sound and practical piece of shop equipment.
The Metal Shaper - (From The Back Cover)
A delightful project with super exercises in pattern-making, molding and casting. Detailed drawings make pattern-making easy and there are extra tips on molding unusual shapes. Many split patterns make the whole job easier. All of the castings are made in the charcoal foundry using the one quart pot, and they are machined on the home built lathe. The manual includes methods and accessories to enable you to use the home built lathe to machine all of the parts except the work table, which is machined on the shaper itself.
Such features as variable speed, adjustable stroke and automatic variable cross feed make this a truly practical machine for the home shop. Comparing the cost of ordinary lathe cutter bits to any single purpose milling machine cutter, you simply can't beat a shaper for economy and ease of operation. You grind the bits to shape on an ordinary emery wheel and you can use both ends. Sharpen or re-shape them in minutes in a simple hand operation.
The maximum stroke is 6" and the mean capacity is better than 5" x 5". The tool head rotates through 180 degrees for angular cuts and it has a graduated scale and simple lock. The down feed has a graduated collar and the yoke is graduated for setting the stroke length. A compact machine with great versatility and generous capacity. With it you can cut keyways, splines, gears, flat and angular surfaces, dovetail slides and irregular profiles to mention a few.
This project really proves the worth of the compact home foundry. You'll acquire a valuable piece of equipment, rarely found in home shops today, and you'll gain still more knowledge and skill as you build your own metal working shop from scrap.
The Milling Machine - (From The Back Cover)
The design of this horizontal milling machine is chosen with the developing home shop especially in mind. There is more detail than in the lathe and shaper but we are still using the same simple methods. All of the castings are within the capacity of the charcoal foundry using the one quart pot. Additional discussion on pattern-making and molding assure that the project is within the grasp of beginners. There are detailed instructions for machining the parts and the miller itself can do some of the operations on its own parts.
The machine is very rigid in its construction. Its lathe like characteristics make it very versatile. Included accessories make it possible to do large diameter turning, boring and facing jobs. It can even be used to make its own cutters. An ideal supplement to a shop with a small lathe.
The work table is 2 3/8" x 12" with a 3/8" "T" slot and it travels a full 12". The carriage travels 6 1/2" in line with the spindle with the tailstand in use and 8 1/2" with it cleared away. The spindle can be raised as much a 6" above the work table. There are eight speeds in two ranges from 43 RPM to 2430 RPM, and the transmission is designed to follow the vertical travel of the spindle without changing belt tension.
It is the milling machine that will enable you to add change gears to your lathe and do other exotic machining operations not possible in many small home shops. There is little beyond your capacity when you complete this project.
The Drill Press - (From the back cover)
Built entirely of home-made castings and standard hardware items, this drill press will make a valuable addition to your shop. It drills to the center of a 12" circle with a quill feed of 2 1/2". Both its spindle and countershaft are mounted in ball bearings. A single lever belt tension mechanism changes speeds quickly. A low speed of 260 RPM enables you to drill 5/8" holes in steel. Its table is adjustable radially for angular drilling. Quill feed is by cable winch or roller chain so there are no racks or pinions to make or purchase.
The machine is carefully planned and designed with the home built 7" swing lathe in mind. All of the castings are within the one quart pot capacity of the charcoal foundry. There is still no need to have any work done at the local machine shop and still no need to purchase any expensive tooling or accessories.
Though building a drill press may be the most difficult project in the series to justify, considering that a very serviceable imported machine can be purchased very cheaply, these operations have great training value as you build your shop and develop your skill. It is very likely that you will value the experience far mor than the machine. It will certainly repay you for your labor and patience as you use it for some of the exacting jobs still left to face as you finish building your shop.
The Dividing Head & Deluxe Accessories - (From the back cover)
Now that you have a machine shop you need accessories for the machines. This manual will show you how to tool up your shop to produce the things you want. Making your own tools and accessories is rewarding both in product and pleasure, and it helps greatly to develop your skill.
An angle plate, a set screw chuck and an expending arbor are only the beginning. A clamp dog, threaded mandrels and simple hand reamers are needed in all shops for many operations. Certainly any lathe is improved by a two or four jaw chuck, and a center steady rest for the lathe enables you to do machining operations on the tail end of the stock as well as expanding the capacity of the lathe.
Building a worm wheel dividing head will enable you to do precise indexing for gear making and other dividing jobs on your milling machine. This one functions as a rotary table for the drill press too. This is an accessory seldom found in a home shop. You will be amazed at its simplicity, durability and accuracy.
Learn basic gear calculations and how to prepare the blanks, index them and mill the tooth spaces. Make your own gear toothe cutters from ordinary lathe tool bits at a fraction of the cost of commercially made gear tooth cutters.
Add change gears to the lathe to cut all standard threads from 8 to 80 per inch, both right and left hand and internal or external. A threading indicator is added to the carriage so that you can do accurate threading without reversing the motor to return the carriage after each pass. You'll find that the gear driven fine feeds are much better than the original round belt carriage feed drive on the home built lathe.
You won't want to stop here for much more is easily possible. The dividing head not only divides gears but will also do graduated feed collars and protractors. All divisions through 50 and all even numbers and multiples of 5 through 100. Many numbers beyand are available up to 1,960, and you can easily make a special plate for any number of divisions in a special job. Now that you have your own foundry and machine shop you can have any item of equipment you want, and you can build it yourself from scrap meterials.
Designing & Building The Sheet Metal Brake - (From the back cover)
The main purpose for publishing the "Metal Shop From Scrap" series was to present methods for building such equipment as is normally found in a machine shop. Lathes, shapers, milling machines and their accessories fall into that category easily. A bending brake can certainly find plenty of use in any shop, and many metal working projects can be greatly simplified by the use of sheet metal rather than castings, forgings or other structural forms. It is well that we included it in the series for it has proven to be one of the more popular titles.
This is a welding project rather than a casting and machining project, though obviously some of the members of the brake could be redesigned as castings. You can find much or all of what you need to build the brake at the local salvage yard. This is a light duty portable leaf brake. Of course heavy work will require a larger, heavier piece of equipment, but you will find the basic principles here.
Simple operations such as cutting squarely to a line with a hacksaw or drilling a hole precisely on location require a measure of skill. The ability is gained through understanding basic principles and by practice. "Learn to do it right and apply what you know!" You'll find a worthwhile series of productive exercises in this project, and the result will be a compact sheet metal brake that will greatly expand your shop capability.
The Flowerpot Crucible Furnace - This little jewel is what got me started in metal casting. Lionel walks you through how to make a crucible furnace using plain brick morter, a flower pot and an old popcorn tin. You may think it is unbelievable but I have more than 20 melts in this furnace without much wear on the pot or the morter. As a matter of fact, the pain is still nice looking on the can. You can get this book through Lindsay Books or from Lionels website at backyardmetalcasting.com.
"Lil’ Bertha" Electric Furnace - This book details the construction of an electric furnace that you can use for a multitude of things. For example, melt metal, Heat Treat, Burnout and more. This book is available from Lindsay Books.
Building a Gas Fired Crucible Furnace - (From the Back Cover)
If you happen to be one of those many adventurous spirits who have discovered the delights of metal-casting using a simple solid fuel furnace, you are probably ready to expand your foundry operation. If so, this book is for you.
The truth is, you'll find little here that is really new or innovative. Instead, you'll discover a furnace that uses design principles proven through years of use, but now almost forgotten. This design having been perfected over the last ten years, provides features that are especially useful in the small home shop foundry. The retractable body gives side access to the crucible which makes moving the crucible easier and safer than lifting it out with tongs.
Lighting the burner is easier and safer too. Nearly everyone who has seen it in operation has commented on the very low noise level which makes it much less intimidating than other furnaces. The burner design can even be adapted to other uses such as firing a kiln, burn out oven, or retort. It will perform nicely in any unit where the flame can impinge an internal barrier or the furnace wall.
Common materials are used throughout and no special skills are required. Costs can be so low as to be considered negligible.
And no longer will you need to melt metal outside. This furnace can move your entire foundry operation inside if you have a shop facility where you can provide adequate ventilation and a noncombustable floor.
The speed and convenience of a gas fired crucible furnace can increase your productivity and possibly the size of your castings as well.
Working evenings, you can advance the state-of-the-art of your shop by leaps and bounds, and significantly increase your enjoyment of melting and casting metal.
Making Crucibles - This book by Vince Gingery shows you cow to make your own crucibles for your furnace. Available from Lindsay Books.
US Navy Foundry Manual -
How to Design & Build Centrifugal Fans for the Home Shop -
Ornamental Metal Casting -
Shop Notebook 1 - Jam packed with ideas and small projects by Dave Gingery. Available through Lindsay Books.
How to run a lathe - a book by south bend lathes was published in 1942 details how to level, lubricate and run a lathe. The technology today is much newer but the theory stays the same. This is a good book. Available from Lindsay Books.
Lathe Operations -
Running An Engine Lathe - (From the preface)
The engine lathe is still the most widely used machine tool in the average machine shop. For although it has been replaced by the hand- and power-feed turret lathes, the automatic screw machine, and various special machine tools, these are only profitable where duplicate parts are to be made, not necessarily in mass production.
The average shop, especially the repair or job shop, still depends largely on the engine lathe owing to the great variety of work that can be done on it. For this means a knowledge of the engine lathe and how it is used is the best foundation for those who want to become familiar with the machinist trade.
An understanding of the workings of the engine lathe, its cutting tools, the turning tapers, the cutting of screw threads, and testing of the lathe for accuracy will make the operation of any other machine tool comparatively easy.
Fred H. Colvin
Machine Shop Projects -
Shaper Operations -
Plastic Injection Molding Machine - This book by Vince Gingery details how you can build a plastic injection machine that can handle up to an ounce of plastic. He also talks about different plastics and making molds for it's use. This book is available through Lindsay Books.
A Plastic Vacuum Forming Machine - This book by Vince Gingery shows you how to build a Vacuum Forming machine. It details the materials you need and covers several type of plastics and also covers how to make your molds. This book is available through Lindsay Books.
Do It Yourself Vacuum Forming -
Clay Modelling and Plaster Casting -
The Clay Lover's Guide to making molds -
The Prop Builders Molding and Casting Handbook -
Methods For Modern Sculpters -
Modeling In Wax for Jewelry and Sculpture -
List Servers
http://groups.yahoo.com/group/casting/ - The Casting List has over 1800 members, from all over the world. NOTE: NEW MEMBERS ARE TEMPORARILY MODERATED TO PREVENT SPAM, so spammers, don't bother! This list covers the following topics: Scratch-building of model masters in a variety of materials, such as styrene, brass, wood, whatever. Making molds out of various materials, including RTV rubber, plaster, epoxy, etc. (anything goes) Casting of the resulting molds in plaster, polyurethane plastics, low-temperature metals, etc. The list is specifically aimed at modelers in any area (model trains, ships, aircraft, etc.), or industrial casters, who wish to create their own models or parts from scratch and duplicate them. It will cover techniques, materials, and other auxillary topics, such as photoetching, vacuum forming, sculpture casting, suppliers, etc. A check of the archives for reference to your topic is suggested before posting, since some topics have been covered numerous times. If you're not sure if your topic is covered here, send me an e-mail at This email address is being protected from spambots. You need JavaScript enabled to view it. and I'll let you know. Regards, Pat Lawless, Moderator
http://groups.yahoo.com/group/Electroplating/ - This group was started to help those interested in electroplating as a hobby or as a small business. Here we share knowledge,experiences,tips and our projects. If you need help in getting started you have come to the right place. Jump in and ask as many questions as you want! An ELECTROPLTING 101 page is being developed at http://members.cox.net/oldies1955/electro/electro101.htm Check it often as it is always in work! Another very good forum to learn from is http://finishing.com They deal with all aspects of metal finishing on the profesional level and much can be learned there also. We will help with questions about all aspects metal plating. Lets help each other,and learn together.
http://groups.yahoo.com/group/gingery_machines/ - Builders and would be builders can trade notes here.Topics discussed might include problems and solutions in building the machines and tools.
http://groups.yahoo.com/group/hobbicast/ - This is the primary forum for interaction between members of the Home Foundrymen's Association. It is a general discussion forum open to both members and non-members with the purpose of sharing information and knowledge between group members and helping to solve casting problems, etc.