Having pretty much taken almost everything there is to take when it comes to classes at my volunteer job, I ended up doing a class in lost wax casting. This is a freaking hard thing to do, as it turns out. What it boils down to is this:
(a) Make whatever you want to make in metal, but first you sculpt it in wax. Turns out that sheet wax and sculpture wax are real pains in the ass to work with, don't stick together that well, don't sculpt that well, and show every bump. So I did not like that part too much.
My goal was to make a guitar pick holder necklace, as I have been pondering buying one or several and thought they seemed kind of expensive. (Now I think they are dirt cheap.) I cut a piece of sheet wax based off of the size of two guitar picks, then made tendrils out of sculpture wax to hold the picks.
(b) Stick a couple of pieces of sprue wax to your wax piece (forms tunnels through which the metal will travel) and attach it to this cylinder doodad holder.
(c) Mix investment with water, pour it into cylinder. That sits around to dry, is later put into a kiln that burns out your wax, leaving a temporary mold. (Neither the mold nor your wax will survive the process. Hence the "lost.")
(d) Get ahold of some metal, which goes into this other doodad machine along with your cylinder. You pick up an oxy-acetalene torch and heat up the metal till it's liquid. Then you set the thing spinning for a few minutes, during which the metal goes into your cylinder mold.
(e) Take out the cylinder and clean it out in a tub, which dissolves the investment. You have a metal piece, which you then need to stick in some vibrating machine and pickle to clean off, cut the sprue channels off of, file, grind, etc. to make it all clean.
Eventually, I came out with this:
This is made out of bronze because I was told it would probably cost $100 to make this in silver. I later sprayed it with varnish a few times to hopefully diminish the future tarnish.