Ceramic Clay Firing Temperatures And Times

Ceramic work is typically fired twice.

Ceramic clay firing temperatures and times.

At the same time the clay body still is quite porous and absorbent enough for easy glazing. The temperature needed to transform soft clay into hard ceramic is extremely high and is usually provided by a kiln. It is bisque fired and then glaze fired. The clay goes from this soft totally fragile substance to one which is rock hard impervious to water wind and time.

Very low fired overglazes and lusters are then applied to the. People want to know if they can fire a certain clay to a certain cone. Because the bisque firing has already changed the clay into the ceramic material glaze firings can increase temperatures faster at the beginning and middle of the firing. As well as firing clay the glaze must also be fired to maturity.

Firing converts ceramic work from weak clay into a strong durable crystalline glasslike form. Ware must be fired at least once at a higher temperature first in order for the clay body to mature. You cannot fire pottery in a home oven because ovens do not get up to the high temperatures of more than 1 500 degrees fahrenheit that you need for firing clay. First it is important to know that the maximum cone rating of a stoneware or porcelain clay is the temperature at which it vitrifies.

This range is usually used for luster glazes and very low firing overglazes. The goal of bisque firing is to convert greenware to a durable semi vitrified porous stage where it can be safely handled during the glazing and decorating process. The type of kiln used and the firing schedule will also have an effect on the color and texture of the glaze. By cone 08 the ware is sintered and has become a ceramic material.

Firing at cone 06 to 04. Between the range of cone 8 and cone 12 high fire stoneware will mature. Firing clay from mud to ceramic. All cones mature with time and temperature.

Generally bisque firing is done between cone 08 and cone 04 no matter what the maturation temperature of the clay and of the glazes that will be used later. A cone 04 glaze firing schedule with down firing. Firing temperatures cone equivalents. Raku clay is usually bisque fired to cone 04 to 1 clays that are to have crystalline glazes should be bisque fired slightly higher than normal i e.

The ware will often not only go through a bisque firing but also a higher temperature glaze firing. It is important to match the firing temperature of the glaze to the maturing temperature for the particular clay body. We get many questions about clay firing temperatures. This is the hardening tightening and finally the partial glassification of the clay.