Solidification. The process during casting when the molten material changes from liquid to solid state by cooling to a stable temperature. Contraction occurs during solidification as metal shrinks when it cools (see shrinkage). When plaster solidifies it gives off heat (its shrinkage is negligible). The type of mold is important in solidification, as well as the use of a release agent. The cast should be removed as soon as possible from the mold; when completely solid it may be more difficult to remove it (particularly in a ceramic mold) because of shrinkage. Its shape, of course, depends upon the shape of the mold; how well it fills the cavities of the mold depends upon pouring, the gates and sprues. Anomalies of solidification are usually surface deformations. See casting.