Moulds to shape coffee pots, made by Waterford Wedgwood UK. Hollow ceramics are made in plaster moulds. A mixture of clay and water is poured into the mould, and the plaster sucks the water out of the clay, leaving solid clay on the walls of the mould in the shape of a coffee pot. When the solid clay is the right thicknes, the fluid material is poured out from the middle of the pot, leaving the solid pot.
© Science Museum / Science & Society Picture Library