Making a plaster cast
Casting is a process in which a sculpture or a part of a sculpture is reproduced via a mould that can be of plaster or silicon rubber.
A mould for a plaster cast first of all has to be coated with a soap lather, after which several layers of plaster and water are applied with a brush. If a large piece is involved, then a metal armature has to be inserted as well to strengthen the future cast. Before the parts of the mould are put together, the edges have to be thickened with a layer of the mixture for strength.
After drying, the parts of the mould are separated and the cast is removed. The penultimate phase, if a plaster cast is made of several parts, is to combine them into a single whole. At the sites where the parts are joined, visible lines remain that have to be removed by working of the surface, chasing. The final phase in the making of a cast is patination, a process by which a visual similarity with the original material of the sculpture is achieved.