Getting started with clay

Firing clay

A small kiln is a worthwhile piece of equipment for primary schools. Some schools may find that they can come to an arrangement to have work fired by a local secondary school or potter. However, great value can be derived from working with clay, even where there is no possibility of firing the work. Pottery that has been fired is more durable and will not revert to clay when wetted. Earthenware does not become waterproof, however, until it has been glazed and fired a second time. When buying clay and glazes, check their firing ranges.

Slab-built structures will not endure unless fired. If clay sculptures are to be fired they must be hollowed out, otherwise they will crack apart, as the outer edge of the clay will fire faster than the centre. A thickness of about 1cm is usually safe. If a seam of workable clay is available near the school, it could be a very worthwhile project for the children to dig some up and experience the whole process from original raw material to finished piece, fired, for example, in a sawdust kiln.

Clay used for firing must be free of air pockets: as delivered, it is already air-free. If they are not fired, sturdy pieces of ware may be coloured in tempera paint and varnished, but they will not be waterproof.