glaze fit

"Glaze fit" describes how well a ceramic glaze bonds to its underlying clay body or ceramic piece. When a glaze and the ceramic body expand and contract similarly during heating and cooling, they "fit" well, minimizing stresses that can cause cracking or crazing. If the glaze expands more than the body, it can crack as the piece cools; if it contracts more, similar issues occur. Achieving a good glaze fit ensures a durable, stable finished piece with a smooth, crack-free surface. Proper matching involves controlling the chemistry and firing conditions to balance the thermal expansion properties of both materials.