Metal Casting Process
- The first step in any casting process is melting the metal. This involves a furnace, heat source and iron tools to remove or pour the melted metal. In industrial casting factories large amounts of purified or refined metals are melted at temperatures that can be as high a 2000 degrees Fahrenheit. In a home operation, these temperatures can also be produced and usually done so with a furnace made of firebricks and propane heat source, or a large tin can lined with cement. This allows for the proper melting of the metal and very high temperatures gained by the heat retention of the brick and cement.
- Usually metal is poured direct from a cauldron into a pre-cast mold. The cauldron is often the same thing in which the metal was melted. The most common is the cast iron "bucket shaped" cauldron with a pour lip. This can usually be moved around by a wench and tilted mechanically or manually by a worker. At home, you could pour the metal from the furnace pot using tongs or heat gloves. The metal is poured, then cooled until the piece can be broken from the mold.
- To create a mold, a few steps are required. Build a form to shape the mold around. This can be created from any material but typically they are built from wood, plastic, styrofoam or clay. Surround the form with a mold material to "cast" the actual mold. Bear in mind the mold is like a negative three dimensional form of the actual part, and the form is the exact size and shape of the part. Materials typically used for casting are sand that is mixed with a glue, foam, iron, clay or plaster (kiln dried). The mold must be perfectly dry and able to withstand the heat of the metal.
