Plaster-cast
To take a plaster-cast of any figure, bust, medal, etc., it is only necessary to obtain a mould by pressing some soft substance upon it, which when it has hardened may be filled with plaster; the latter soon hardens, and a representation of the original is obtained. The substances used for forming such moulds are various: for some objects a composition of beeswax, rosin, and pitch may be poured round it; for very small objects, wax alone, or the crumbs of new bread, will answer; but for larger ones it is necessary to provide moulds of the plaster itself, or clay may be substituted. A cast of a person's face is obtained by first securing the hair at the back, inserting paper tubes at the nostrils for breathing, and oiling the face, the person lying on his back. The thin plaster is then carefully spread one-fourth inch thick all over, taken away when set, and used for obtaining a clay model, from which to make a plaster-mould, which serves as the matrix for the final cast, and which must be divided at suitable places for easy withdrawal from the face. See STATUE-FOUNDING.