Firing converts ceramic work from weak clay into a strong durable crystalline glasslike form.
Ceramic clay firing temperatures and times.
First it is important to know that the maximum cone rating of a stoneware or porcelain clay is the temperature at which it vitrifies.
Firing temperatures cone equivalents.
However anywhere from 2305 to 2336 1263 to 1326 may be appropriate depending on the specific clay used and desired effect.
The average firing temperature for high fire stoneware is 2381 1305.
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.
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.
The ware will often not only go through a bisque firing but also a higher temperature glaze firing.
People want to know if they can fire a certain clay to a certain cone.
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.
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.
We get many questions about clay firing temperatures.
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.
Ware must be fired at least once at a higher temperature first in order for the clay body to mature.
The temperature needed to transform soft clay into hard ceramic is extremely high and is usually provided by a kiln.
As well as firing clay the glaze must also be fired to maturity.
As a kiln is firing up and cooling down the changes in temperature make some profound changes in the clay.
It is bisque fired and then glaze fired.
Very low fired overglazes and lusters are then applied to the.
At the same time the clay body still is quite porous and absorbent enough for easy glazing.
A cone 04 glaze firing schedule with down firing.
By cone 08 the ware is sintered and has become a ceramic material.
This is the hardening tightening and finally the partial glassification of the clay.
This range is usually used for luster glazes and very low firing overglazes.
Between the range of cone 8 and cone 12 high fire stoneware will mature.
Firing at cone 06 to 04.
It is important to match the firing temperature of the glaze to the maturing temperature for the particular clay body.
The clay goes from this soft totally fragile substance to one which is rock hard impervious to water wind and time.
Ceramic work is typically fired twice.
