The formed pot is called "green ware". A green ware pot can be melted back down to being a glob of clay simply by adding water. Before the pot can be put into a kiln it must be thoroughly dried. This can take up to a week depending on atmospheric conditions and the thickness of the clay.
When the pot is no longer cool to the touch is it probably bone dry. Some people also test it by licking the clay. It should stick to the tongue. I don't do that. If the bisque firing is started slowly, any residual moisture will be driven out. It does need to be no longer cool to the touch. If it is cool to the touch, that indicates moisture is still evaporating (thus cooling the pot).
Usually the kiln should be as full as possible. Bisque firing does not bring the clay to a temperature where it is viscous (liquid) so the green ware can be stacked as close as possible. It won't stick together.
I like to fire any multi-part pot with the parts in their expected place so if a pot has a lid I like to do the bisque firing with the lid placed on the pot. If you don't do that, the lid or the pot could warp and not fit well. If they are together they will shrink the same amount.
The kiln is fired to a temperature sufficiently high to harden the clay. For stoneware clays this is normally about cone 05 (1050 °Centigrade, 1900 ° Fahrenheit). You can't heat the kiln as fast as possible; the kiln temperature must be brought up slowly to avoid breaking the pots by thermal shock. Certain temperature points are critical.
|100||212||water turns to steam|
|225||440||cristobalite (a form of silicon oxide) rapidly expands|
|573||1050||quartz (another form of silicon oxide) rapidly expands|
|900||1652||the clay is now strong enough to take normal handling|
Once you get above 600° C the clay has been transformed and will no longer melt by just adding water. The chemically combined water is driven off at that temperature.