The main part of the article, which is produced by a moulding process called casting,is the clay body. The major components of the clay body are felspar, ball clay, china clay, silica, and water. The materials are ground to a fine particle size in water by a process called milling. This allows the components to become finely ground and intimately mixed. The slurry produced, which has the consistency of cream,is called 'slip' and is stored in huge mixing vessels called blungers. The slip is sieved through a fine mesh and passed over a magnet to remove coarse and metal particles that may be present. Slip is approximately 70% solid and 30 % water so that when it is poured (cast)into a porous mould it assumes the shape of the mould. With time some of the water is extracted by the mould leaving a semi solid cast piece.