"Harold and Susan Vordos" wrote in message
...

"Andy Dingley" wrote in message
...
On Wed, 09 Nov 2005 07:49:54 GMT, mark
wrote:

Could a person melt brass or bronze

Go with bronze ("copper" loose change is good, but sort it with a magnet
first) Brass has the problem of zinc boil-off, which is significant for
small loadings.

Not with US coinage. Early pennies are copper/zinc alloy, and newer
pennies are copper plated zinc. The balance of our coins are either
nickel/copper alloy, or nickel copper sandwiched. There are no bronze
coins
made in the US.

Harold

[I believe the new Sacajawea dollars are manganese bronze, but it would be
rather uneconomical to melt them down. Send them to me, and I'll give you an
equal weight in new silicon bronze ingot, the American foundryman's
overwhelming choice...

As for the Original Poster's question, yes - you can pour brass in a mold.
No, straight plaster of Paris isn't a good idea. Yes, you need to heat any
plaster-based investment to drive off the chemically-entrained water; 1250F
is a good temperature for that. No, you don't have to buy jeweler's
investment; you can add 2 parts sand by volume to 1 part plaster of Paris to
give it sufficient strength to withstand burnout. Yes, you can melt bronze
in a crucible with an oxy-acetylene torch, but no, that won't give you
enough to pour with straight gravity. For small amounts of metal, you need
some way to overcome surface tension, like vacuum from the bottom of the
flask, or centrifugal force, or even steam pressure. If you want to melt
enough to pour by gravity, then you need a furnace to melt in. Yes, you can
improvise a crucible with a steel pipe or whatever, but no, this isn't a
good idea - the temperature of molten bronze is too high, and the
consequences of a crucible failure are too dire. Get a real clay-graphite or
silicon carbide crucible; they aren't that expensive compared to
hospitalization. (Of course this doesn't apply to the British, who get
hospitalized for free...)]

Andrew Werby
www.unitedartworks.com