Adventures in Metallurgy
To someone interested in costuming, the ability to cast metal objects is really useful. You can make buttons, belt buckles, coins and brooches, rings and jewellery, and all manner of other nifty hard metal objects.
I've seen it done before, years and years ago, and I thought it was really neat. I even went so far as to buy some mold material and metal ingots last year but predictably I never did anything with them. Now that's changing.
To cast metal, you need metal, something to melt the metal in, and a mold into which you pour the metal, plus all of the obligatory PPE (Personal Protective Equipment, that's my Navy days creeping in).
Metal can vary widely. Pewter is easiest due to its low melting point, but aluminum and zinc are easy enough to melt at home, with melting points ranging from 550 degrees Fahrenheit (for some pewter alloys) to 1120 degrees (for aluminum). Copper, gold and silver require slightly higher temperatures (around 1900 degrees or so), but it's still fairly achievable with not too much effort.
Melting the metal can be done with an electric hot plate, or with a torch, or with a more complicated forge-type setup. Propane, acetylene, and such are all fine choices depending on just how hot you want to get (mixing in appropriate amounts of oxygen of course).
The mold can either be carved (for new work) or cast itself (to copy existing work). Plaster works for casting molds, as does rubber and some silicones. Molds for new work can be carved from whatever can stand the heat of the molten metal, usually some sort of stone although wood can be used if you don't need too many castings and the detail doesn't need to be fine.
This year I took a hands-on class on casting, and the results are below:
The mold is soapstone, which is pretty soft and easy to carve, but also easy to botch. I think I'm going to gravitate towards something harder. The hand tools are simple wood carving tools, with a variety of shapes and sizes of carving tips. The metal used was a pewter alloy of 90% tin and a few percent of bismuth and antimony.
Lead pewter is traditional, but then lead poisoning is traditional too. You have to limit the percentage of bismuth because bismuth is one of the few substances on Earth which does not shrink as it cools, and too much bismuth will result in a casting that is stuck in its mold.