Re: Bronze Clay?
Steve, the wax would burn out and the bronze powder would sinter (fuse) together, forming solid bronze. The process would be identical to that used for Precious Metal Clay (Silver Clay), which consists of powdered silver in a resin binder. The piece would be fired in a kiln at a temperature high enough to burn out the wax, but not high enough to melt bronze.
Your response suggests that you're assuming this is a casting process. It is not. The "metal clay" would consist of powdered bronze suspended in either a resin binder or, as I advocated, microcrystalline wax binder. It would be pliable and you'd model your sculpture with it directly. To get a "bronze," you'd then fire the piece in a kiln, vaporizing the binder and leaving only the sintered bronze powder, which becomes solid bronze. The object is not to melt the bronze and pour it into a mold (which would make the whole modeling process pointless). This is intended as a cheap, direct substitute for arriving at a bronze casting, as it totally eliminates the casting process altogether.
I haven't tried this, as there is no such commercially available product; just silver and gold "clays," which are used in jewelry making. They shrink by 30% as the binder vaporizes, leaving behind sintered silver or gold. The same process should be applicable to any metal, though. All you need is powdered metal, suspended in some type of binder that can be easily burned away at relatively low temperatures. You can even "hand fire" Precious Metal Clay with a butane torch. If you substituted bronze powder, the firing temperature would probably have to be modified, but the process and result would be the same. Gold clay fires at a higher temperature than silver clay, so I would imagine bronze clay would fire slightly higher than gold.
Last edited by GaryR52 : 08-23-2005 at 03:58 PM.