"JohnM" wrote in message
m...

Another dangerous trick that works, again from the jewelry business, is
"diecasting" precious metals into a plaster mold, using a wad of wet
newspaper for a diaphragm. You have a pool for the metal cast into the
top
of the mold and a short and narrow sprue leading straight down to the
mold
itself. You fold up about 1/2" of wet newspaper into an 8-in.-square wad
and
soak it. When you pour the metal into the pool, you immediately lay the
wad
of newspaper on top of it and slap it with your hand.

This is a good way to splatter molten metal onto yourself and suffer
permanent damage. My uncle was an expert at it. He wore a full-face o/a
welding shield, a leather welding jacket, and leather welding gloves. He
didn't used to, and he had some interesting scars as a result.

--
Ed Huntress



Yeow.. I'd like to see that done. What's the purpose? To ensure filling
a cold mold?

Yeah, it's good for items with thin sections and detail. It really puts some
pressure on the metal if it's done correctly.


My favorite is a lost-wax process where the pattern is left in the mold
and the mold and casting material is enclosed in a clay egg.. Put it in
the fire with the mold up and you get the burnout, wait 'till the thing
is hot enough that you know your metal has melted and turn it over and
the metal enters the mold. That always seemed like a cool way to do
things.

That's another interesing one. I wonder how many of these one-off casting
tricks have been lost in time?

--
Ed Huntress