How to Cast Brass. Brass is an alloy of copper and zinc. It's sometimes confused with bronze which is a completely different alloy of copper and tin. Brass can be cast into many forms such as house numbers, wall hangings, and cabinet knobs. It's used in musical instruments and any place where low friction is required, like in locks. The process of casting brass should only be done by someone who knows about metals.
Things You'll Need
Home foundry furnace
Large bin with cold water
Make a mold of the shape you'd like to cast the brass in. A mold can be made out of rubber, plaster or sand. For the do-it-yourselfer, green sand may be the best choice. It's a mixture of silica sand and clay for binder with some cornstarch to help with the absorbing of moisture.
To mix, figure out 25 percent of the amount of sand you have to find out how much clay to add. One percent of the amount of sand is the percentage of cornstarch you add.
Melt any brass scraps in a furnace. Be sure to use a container that can withstand the heat. An iron pan usually works well. The melting point of brass is around 940 degrees Fahrenheit.
Pour the molten brass into the mold you made. Let set for an hour or much more, depending on the size of the brass piece you cast.
Use the tongs to place the mold in a cold bath. The heat difference should crack the mold right off leaving you with a still hot finished piece. Cool thoroughly before using.
Any type of foundry work can be very dangerous, since it involves the use of heat and fire. Wear protective body and eye gear.