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DIY Copper Clay Trilobites

Picture of DIY Copper Clay Trilobites
Learn how to make your own 'metal clay' using powdered copper and organic binders. 

The first precious metal clays were introduced in the 1990's - made from pure silver powder and organic binders (Mitsubishi Materials Corp. makes PMC = Precious Metal Clay and Aida Chemical Industries makes Art Clay).  The silver clay behaved kind of like a ceramic clay, could be molded, sculpted, carved, extruded etc.  The metal clay was then 'fired' in a kiln or by torch, to produce a pure metal item.

Fine silver (.999 pure silver) is a noble metal, meaning that it resists oxidation and corrosion.  Many noble metals are also precious metal, gold, silver, platinum.  Because it resists oxidation, fine silver can be fused by heat in an oxygen (normal atmosphere) environment such as in a kiln or open torch flame.  When particles are heated, close to melting temperature, but not melting, they move close together and become sticky, adhereing to each other.  This compaction and partial fusing is called 'sintering'.  Sintering produces metals that are more porous and lighter than cast metal, also not as strong.  Gold clay later became available, but required higher firing temperatures and was very costly.
Precious metals are costly, and in recent years have grown even more expensive.  Many people worked on trying to make 'base metal' clays.  Base metals, such as copper, bronze (copper and tin) and brass (copper and zinc) do oxidize and corrode.  When heated in an oxygen atmosphere, base metal particles oxidize and do not stick together (sinter).  Industrially, metal powders are sintered in special kilns filled with inert gases.  This is virtually impossible to do in a home or small studio setting.  The inventor of BRONZClay (tm) and COPPRClay (tm), Bill Struve, found a wonderful way to fire base metals in a home kiln.  He used activated charcoal  in a closed, stainless steel container to produce a low oxygen environment for sintering base metal clay.  When heated to high temperatures, the charcoal tries to burn and uses any available oxygen in the area, thus preventing (and even reversing) oxidation of metal particles.
 
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ruthinator1 year ago
This made my day, thanks for posting this! About how much shrinkage do you think you get after firing?
Very cool. You did a great job! :)
paqrat2 years ago
Its a shame there aren't programs here that would teach people how to do that. Much of the glass that ends up in landfills could be used.
paqrat2 years ago
Very, very cool instructable. Thank you. I don't know if I will ever use the concept but I am very pleased to know how it can be done. It reminds me of an article I read years ago about casting glass. Similar to lost wax casting, they mixed fine glass pieces with a binding agent ( I believe they used Elmers glue.) and formed the mixture into the shape they wished to cast. Either with a mold or hand formed. Once the material had dried sufficiently they then used a casting medium ( investment akin to plaster of paris but able to take much greater heat) and put the piece in a cask then poured the investment into the cast. After the investment had dried they then put it in a kiln and ran the temp up to a point where the glass would fuse. The binder burned off in the kiln leaving a fused model in the investment. Then came the cool down process. Glass must be cooled slowly or it will break. I believe the cool down process took days. I think Lalique made some glass items by a true lost wax process.

wombatmorrison (author)  paqrat2 years ago
Thanks. I've played a little with homemade 'glass clay' - glass powder held together with an organic binder. I did not fire it in a mold - just on a kiln-washed shelf. I believe that there is a history of recycled, powdered glass beads made in Ghana... crushed glass powder mixed with colorants and packed into kaolin-coated clay molds and fired in wood-burning kilns. I think skilled artisans use the color of the kiln walls to estimate firing temperatures.
wombatmorrison (author) 3 years ago
Somebody sells powdered silver with a binder for DIY silver clay - I think it doesn't handle as well as PMC or Art clay silver. I forgot the name, but it's listed on the metalclayacademy website, under make your own metal clay.
Aluminum metal clay sounds difficult: aluminum oxidizes so quickly...
westfw3 years ago
Cool; I've been wondering whether it was possible to make any of your own metal-clays from metals less dear than silver. This describes both why it's difficult and how to do it anyway. (next up, Aluminum?)
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