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The Bisque process hardens the ware making it easier to handle without breaking during the glazing process. Clay fired at this temperature still retains its porosity, however. The porosity of a material refers to its ability to absorb a liquid. The liquid part of glaze, in this case water, is absorbed by the porous bisque ware, and the glassy materials in the glaze are left deposited on the surface of the bisque ware. So, the bisque process is typically done to make glazing easier.
The bisque firing can take a total of 3 days from start to finish. On day one, the kiln is loaded with the dry greenware and the kiln is preheated, set at a low setting to dry the ware, and left overnight to slowly warm. Firing too fast during this early stage of the firing can easily cause the work to explode. On day two, the kiln is gradually turned higher and the temperature rises until the target temperature of around 1800°F. is reached. The kiln is then turned off and allowed to slowly cool. On day three, the kiln is opened, the bisque ware removed and the cycle repeats.