Clay glossary

A moderately porous pottery body that is fired to a temperature somewhat below that required to produce a vitreous article. Typically 1060 to 1100 C

A type of mill used for grinding or mixing materials in which the treatment is carried out by the pressure of large rollers squeezing the material between themselves and the base of the pan.

A growth on the surface of ware due to the presence in the body of soluble salts.

Made for the use as an electrical insulating material. Typical composition is ball clay 28%, china clay 22%, quartz 25% and feldspar 25%.

The separation of particles according to their size or specific gravity by a controlled velocity water stream. The basis of a method for the determination of the fineness of a material.

A fusible vitreous coating, fired at low temperatures, for clay articles.

A further firing to convert ceramic colouring materials, applied on top of a glaze, to a permanent form.

A white or coloured coating of slip applied to the clay, for decoration, before glazing.

A mixture of two substances which has the lowest melting point in a whole series of possible compositions.

The process of forcing clay through an aperture or die. e.g. through a pugmill.