"Jud Turner" wrote in message
oups.com...
Anyone know if you can burn out an alumilite master when doing sand
casting? I know you can burn out foam/stryofoam, but how about
alumilite? (www.alumilite.com)

A customer has an alumilite gerbil character that he wants done in
metal, and it'll be a lot cheaper for him if I can just use (and
destroy) his original alumilite gerbil rather than carve a whole new
one.

thanks for any info...

The resin in Alumilite is thermosetting polyurethane. It will not burn out.
Most of the mass will turn black and just remain where it is.

As someone else suggested, you'll need to make a transfer molding from it.
Assuming this character has some undercuts, either a strippable latex
molding compound (cheap and easy); a silicone mold-making compound
(expensive and possibly easy, depending on configuration); or a multi-part
plaster mold (very cheap and probably difficult, as it would have to be made
in multiple, keyed-together pieces) will do the job. There are other
flexible molding compounds, including glue molds and gelatine molds, but
they're for artists and for people who want to spend their time playing with
mold-making rather than making parts.

There are more expert casters around here who may disagree with this, but my
limited experience with art casting suggests to me a dipped-latex or
silicone mold; a wax (probably a special one made for investment casting)
pattern cast in the mold; and a metal-casting-plaster mold in which you
"invest" the wax pattern, which you burn out before casting. The plaster for
metalcasting is available from art supply stores, casting supply houses, and
U.S. Gypsum.

This is not something you're likely to get right the first time you do it,
but, once you have it down pat, none of it is difficult to do.

--
Ed Huntress