- Last Updated: Thursday, 19 June 2014 19:43
The phenomenon of shivering is when the fired glaze flakes or falls off ware after completing the firing process, much like a paint chip peeling from a surface. It can happen immediately during the cooling process or delayed in time. Raised edges and rims are the most commonly affected areas. First of all, handle with care as the fired glaze is literally a sliver of glass that can cut the person handling the piece.
The most common cause of shivering is a mismatch between the coefficient of thermal expansion (CTE) of the clay body and the glaze; i.e. the glaze CTE is much lower than the body CTE. Coefficient of thermal expansion is a measurement of the ceramic ware’s expansion and contraction during the heating and cooling process of firing. When the clay body shrinks more than the glaze, the glaze becomes compressed and will not adhere to the fired clay body.
There is no salvaging the affected piece. We would recommend that you broaden your testing to determine the best course of action. If you find that a particular glaze shivers over a variety of clay bodies, you might discuss the problem with the glaze manufacturer or switch to another glaze. If you find that several different glazes fail over the same clay body, contact the clay manufacturer for recommendations.