i used to. i started out with silver, worked my way up to gold.
basically, a lot of jewelry starts out as a piece of red wax. then a sprue is added to that, and it's suspended in a cavity & investment is poured all around it.
investment is like Plaster of Paris but, it's more porous, not air tight (not that Plaster of Paris is air-tight ... they're just similar).
when the investment is hardened, the wax is baked off at about 1100 F.
once the wax is baked off, you have a cavity that is real similar to the original wax piece.
then hot metal is poured in, using one of 2 methods, centrifugal & vacuum casting. you need a way to force the molten metal into the far reaches of the cavity.
as far as the piece of wax you start with ... there are 10's of thousands of different shapes. or, you can carve your own, which is what i usually did.
Facebook
Twitter