Sand Casting, also known as Sand Molding, is a metal casting process characterized by using sand as the mold material. Molds made from sand are relatively cheap and sufficiently refractory, even for steel foundry use. In addition to the sand, a suitable bonding agent (usually clay) is mixed with the sand. The sand is typically contained in a system of frames or mold boxes as a flask. The mold cavities and gate system are created by compacting the sand around the models or patterns.