"Roger Hull" wrote in message
s.net...
I have zero foundry experience. I want to melt a few pounds of Copper and
cast it into backup plates for welding. What should I make the crucible
and
moulds out of? OR, is it possible to buy a crucible somewhere?
Thanks.

Roger in Vegas
Worlds Greatest Impulse Buyer


I'm not convinced your plan is well conceived. If you've never worked with
molten copper, you're in for some unpleasant surprises, one of which is the
casting temperature is relatively high, over 2,000 F. It's a bitch to
work with in that it often comes out quite porous. It loves to solder
to almost anything it contacts, to add insult to injury. I can't help
but think you'll spend a lot more money trying to make your copper pieces
than you'd pay for some scrap buss bar at your local recycling place, but if
you're hell bent on melting copper, you'll need a decent furnace, fuel to
fire it, a proper handling tool, as well as a reasonable crucible. One
made of steel won't do well unless you cover it with a wash, otherwise the
copper will dissolve a percentage of the steel and ruin the copper to some
degree. You also risk dissolving through your container if it's very thin.
I'd suggest a graphite clay crucible, or even better, a silicon carbide
model. Bottom line, unless you'd like to do some casting in the future,
you'd be far better off not trying to cast your own plates. The cost of
getting set up is prohibitive if that's your only purpose.

Assuming you get so far as to actually melt your copper, you could probably
use a heavy channel with plates welded on the ends for a mold, but it will
need some mold dressing so the copper won't solder to it. You won't achieve
flat castings, but they'll be close.

Foundry supply houses sell a mold dressing, and would be the source for a
decent crucible and a handling tool. You'd probably have to build your own
furnace, although they sell them, too.

I used to melt scrap copper to cast bars for silver recovery. It was less
than pleasant, and I had the equipment at hand.

Harold