Anyone can cast metal at home with the right equipment, a bit of skill, and caution.
As a simple example, let's say you want to cast a flat, star-shaped pewter piece with a large, circular hole in the middle. You'll need two pieces of plywood and a wood block to make the mold. The wood needs to be very dry, so pass a soldering torch over it to burn it slightly.
Cut the star shape out of one piece of plywood with a piercing saw. (Make a straight cut-line from the edge of the plywood to the cutout star; this will be useful for removing the finished piece later). Firmly nail this plywood onto the wood block. Now you have a star-shaped depression to pour the pewter into. To leave a circular hole in the middle of the star, cut the circle shape out of another piece of plywood (same thickness as the first piece). Nail it into the center of the star shape.
To melt pewter, put it into a small, handled tool, such as a ladle. Cover the cup part of the ladle with a wire screen. This will help hold back any chunks or debris so only liquid pewter pours out. Now heat the ladle over your soldering torch or camp stove. When the pewter has melted, carefully pour it into the mold. You may need to tilt or tap the mold gently so that the pewter flows into the points of the star. When the star has completely cooled, use a screwdriver or similar tool to pry the plywood off the wood block. Gently remove the pewter star. That's all there is to it!
Casting in silver is more challenging but highly satisfying. One of the most popular casting methods, "lost wax," is achieved by replacing a wax model with molten metal using centrifugal force. Shop around for casting equipment; you may purchase pieces separately or buy a starter kit.
To begin, carve a model of your desired piece out of wax. Next, you'll need to slightly melt the end of a sprue (a wax rod that will act as a channel during melting) and attach it to the model. The sprue is now ready to be mounted onto a sprue base (a rubber base specifically designed for holding the model in a stainless-steel flask).
Now you're ready to invest, i.e. cover your figurine with plaster. Be sure to protect yourself with rubber gloves and a good dust mask. Mix investment powder (following label directions carefully) with water. Avoid making bubbles, as they can create bumps on your finished piece, and use a vacuum pump to remove any air from the investment. Pour the investment into the flask, and use the vacuum pump again to get rid of any bubbles. After allowing the investment to harden for about half an hour, you can remove the rubber base. Wait at least two hours (overnight is best) before the next step.
In a small kiln, set the flask, open end down, on a brick or screen so that the wax may flow out. Heat to 1250°F (670°C). When it reaches this temperature hours later (exact time may vary), shut off the kiln. Prepare your casting machine according to the manufacturer's directions. Place the hot flask into the machine with tongs. Now heat your silver in the crucible over a reddish flame, adding a bit of flux as it begins to melt. When the metal has liquefied, release it into the investment cavity. The centrifugal force created by the machine will press the liquid metal into every detail of your mold. Wait for the machine to stop, and then use tongs to remove the flask. Quench the flask in a metal bucket of water. This will release some terrible fumes, so be sure to do it in a very well ventilated area while wearing a respirator. The plaster will start to crack off; help it along with a dull knife or similar tool to reveal the cast piece.
