What is polymer clay?

Polymer clay is, in a word, plastic.  However, that is too simple.  As we know, plastics have evolved enormously in recent decades. There are many different levels of plastic, from "cheap" plastics that dollar store items are made from,  to the super plastics, used in medicine and space.

Because polymer clay is NOT a traditional earth-based clay, it is not surprising that it is used for completely different applications than traditional clays.  Generally speaking, polymer clay is used in making miniature and doll sculptures, in jewelry making, in covering an endless list of objects, and in ways that are like three dimensional painting.

There are several different brands of polymer clay, the best known being Fimo and Sculpey.  Polymer clay is the generic name that is used in the industry.

Polymer clay fires at a much  lower temperature than traditional earthen clays and a kiln is not needed.  The average firing temperature (we also call it "curing") is about 270 degrees Farenheit, so it can be cured in a typical home oven.

Another aspect of polymer clay that makes it very different from traditional clay, is its ability to pick up and hold impressions of the most minute detail.  It will pick up the texture, lines and detail of whatever presses against it, which includes finger prints, the weave of fabrics, or the veins of a leaf.

When cured, the strength and hardness of polymer clay varies from brand to brand.  It is much more expensive than earthen clays.  Because of these two factors, polymer clay is not really meant to be used to create whole vessels out of, such as bowls, vases, cups, etc.  The brands of clay that are stronger when cured, tend to also be flexible and a bit soft to the touch..  The brands that are harder and more rigid, when cured, tend to be brittle.

Because of this, polymer clay artists frequently use a solid base material, and cover it with clay design and sculpture.  Glass is a popular material to cover, as is metal and wood, which are a little harder to work with.

There have been many questions and discussions as to the toxicity of polymer clay.  There is a lot of misinformation that has been passed around on this subject and is based on older versions of pre-polymer clay molding materials.  The polymer clay brands in general use today are rated as non-toxic art materials.

 *Update*  Beginning in 2008, nearly all of the manufacturers changed the formulation of their clays to remove the small amounts of PVC used, because of the controversy about its toxicity.  Eberhard Faber, the maker of Fimo, was the first and required to do so by law.  The major American manufacturers followed suit voluntarily.

Polymer clay is also slightly porous, which is why it is not recommended for use on the parts of containers that will have food in contact with them.   Because of this porous nature, minute particles of food and foodbourne bacteria could become trapped and contaminate the item for further food use.  This, however, has not been proved or disproved by research, as yet.  This, however, is the reason it is not recommended for use for food items, rather than any toxicity to the clay itself.