So, let's start with the basics on polymer clay.

Also sometimes called oven-bake clay, it's an artificial PVC-based clay that doesn't dry out or harden. If you ever do find your clay is crumbly or stiff and hard to work, it's easy to rejuvenate it by adding more plasticizer; this can be a branded clay softener like Sculpey Diluent, or just regular mineral oil or petroleum jelly. Personally, I like to mix in very small amounts of the extremely soft Sculpey Mold-Maker clay - I usually have plenty on hand, and in small amounts it really doesn't affect the color of the main clay body.

Once you've shaped your clay the way you like it, you can easily cure - that is, permanently set it so that it is solid and can no longer be worked - by baking it in a home oven. Most polymer clays cure at temperatures between 250 and 300 degrees Fahrenheit. Typically, the baking time is dependent on the thickness of the clay as measured at the widest point.

There's some wiggle room here, and it can get a little confusing when you're mixing clay types with differing requirements - for example, what do you do if you make a sculpture out of Fimo, with Granitex and Premo accents? And what if you're baking something very thin?

Fortunately, there's a decent margin of error in baking polymer clay - it will tolerate a bit of overbaking. I like to add 20 minutes to the baking time if I have any doubt, which usually works well for me.

For more information about baking polymer clay, check out Polymer Clayer's article on the subject!