Polymer clay's history as an art medium is only decades long, unlike many media that have been around for centuries and have long traditions. This newness means that there is a great deal of innovation by users of polymer clay. Often, ideas are born by borrowing from the traditions of some other materials, such as metalworking (mokume gane), ceramics, glass (millefiore), paper, etc.
Polymer clay hardens by curing at temperatures created in a typical home oven (generally at 230 to 275 °F (110 to 135 °C), for 15 minutes per 1/4" (6 mm) of thickness), and does not shrink or change texture during the process. When properly cured, most clays create items which won't break if dropped or normally stressed. It also comes in liquid form and in permanently flexible solid form, as well as specialty formulations such as eraser clay and glow-in-the-dark clay. A piece may have additional layers or enhancements added to it, and re-cured with no ill effect. As long as the maximum curing temperature is not exceeded, there is no limit to the number of times a piece can be re-cured.
Few tools are essential for use with polymer clay, and these can often be found around the house. A pasta machine is often used to create evenly flat sheets, to mix colors, to condition the clay, and to create patterned sheets.
Clays can be mixed together to create new colors, gradient blends, or other effects. Judith Skinner] was credited with a technique which uses a pasta machine to create gradient-blended sheets of color. This technique is used frequently in many other applications and is one of the early skills developed by hobbyists or artists in the medium.
Polymer clay can be colored with other media. Paint, ink, colored pencil, chalk, metallic (mica-containing) powder, metallic leaf and foil, glitter, and embossing powder can be applied to the surface. The same materials also can be mixed in as inclusions; this is often done with translucent clay. When acrylic paint is cured onto the surface, it forms a permanent bond with the surface.
After it has cured, the clay surface can be left as is, sanded and buffed, or finished with a varnish.
