"Michael D. Callahan" wrote:

    Not trying to sound like a know it all by replying to every post someone makes,
but I have a really cheezy aluminum foundry and have done some sand casting. The
styrofoam molding technique you mentioned is called the "lost foam process" and I
have seen it work at a local art foundry in cast iron, but you don't have to use
beaded foam unless you are trying to get into mass production.

    Blue foam works. Make your part out of blue styrofoam insulation or beaded
packing foam, allowing 1/4" per foot for shrinkage. Take a METAL garbage can or
55gal drum and put a foot or so of DRY (even small amounts of moisture can cause an
explosion) sand in the bottom. Put your pattern in and start filling the garbage
can. (If you put a small wood block under the bottom edge of the can, you can rock
it back and forth to help settle the sand as you go.) When you get near the top you
can make a pouring sprue by putting a 1"x1" length of foam on the top of the
pattern and sitting a small clay flowerpot with the bottom knocked out on the very
top for a funnel.
    The hot metal melts out the foam and leaves a fairly smooth surface that only
needs to have the sand brushed or blasted off.  Mike C.

Thanks Mike. How do you melt your aluminum? I have a small electric oven
that goes to about 2000 F but it is only about five inches cubed.

Paul Lamar
 
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