The two basic types of clay used as a modeling material are hardening clay and non-hardening clay. Hardening clay hardens in one of three ways: by fire in a kiln, by baking in an oven, or through the process of air drying. Non-hardening clay is malleable and reusable. Several types of hardening clay harden in a regular home oven rather than through kiln fire or air drying. Both of these types of clay are used to create permanent vessels, art pieces and figurines.
Polymer Modeling Clay
Polymer modeling clay is available in a variety of colors and textures for making jewelry, miniatures, doll heads and art projects. Two popular brands of polymer modeling clay are Sculpey and Fimo. Both brands can be hand modeled or pressed into molds; rubber-stamp impressions and heat-resistant embellishments may be incorporated into the soft clay prior to baking. It takes about 15 minutes to bake polymer modeling clay projects in a regular home oven.
Polymer Modeling Compound
Sculpey also makes a polymer modeling compound that you can bake in a regular home oven. Its polymer modeling compound differs from its polymer modeling clay in that the compound creates a porcelain-like finish. Create pottery, jewelry and artistic ceramic projects using the modeling compound. The modeling compound is available in either white or terra cotta. Create projects using molds or by hand modeling. Carve, stamp or embed heat-resistant objects into the soft modeling compound. Paint the finished project with acrylics or latex-based paint.
Laguna OvenCraft Clay
Another brand of modeling clay that hardens through baking in a regular home oven is Laguna OvenCraft clay. OvenCraft clay differs from polymer modeling clays in that you can throw it on a potter's wheel, hand model the sculptures or press it into a mold. OvenCraft modeling clay hardens after baking for one hour in a 350 degree oven. The finished project resembles red-brown speckled stoneware. Paint or stain the finished project using any finish medium.
According to CanTeach.com, a few homemade clay recipes harden by baking in a regular home oven. One recipe calls for blending two parts flour, one part salt and one part water for two minutes to create the clay. Create projects using hand modeling or molds, then bake the clay for one hour in a 275 degree oven. After the clay hardens, you can paint it and preserve it with a clear varnish.