How do you harden clay?

Clay is hardened traditionally by firing it in a kiln, a special oven that heats clay from all sides at high temperatures simultaneously. However, there are also special formula clays available that self-harden without heat or that can be heated in an oven.

1. Identify the style of clay that you are working with

   Determine whether you are working with traditional clay that needs to be fired in a kiln, self-hardening air-dried clay, or clay that is designed to be re-sculpted, such as Crayola.

2. Prepare the clay for hardening

   If you are using traditional clay, it needs to be fired inside of a preformed mold. If you are using self-hardening clay, it should be sculpted prior to drying to achieve the desired form. Reusable clay such as Crayola is not designed to harden and should not be heated.

3. Fire or air-dry the clay

   Once a mold has been filled with traditional clay, it can be fired in a kiln until it dries out and hardens. Allow self-hardening clay to dry out according to the manufacturer instructions.

4. Remove the clay from the mold

   Allow the clay to cool and return to a safe temperature before handling the mold to avoid cracking or breaking the dried clay.