One of the most difficult aspects of working with polymer clay in my opinion is the baking. It is very easy to burn the clay if you are not careful. I originally sent this out as an e-mail message and it was reprinted later in Rubber Bytes magazine.
It is not recommended by some that you bake in the same oven that you use for baking food. I purchased a used rotisserie oven from a neighbor and I use that. A toaster oven is excellent and not very expensive. I bake outside to avoid the fumes, which I've heard are not good for you at all. Even in the dead of winter this works. Use a heavy duty outdoor extension cord that can handle the load and is in good condition. Try not to run any other appliances that use a lot of energy at the same time so you don't blow a fuse (like dryers, toasters, microwave, space heater). I can't tell you how many fuses I've blown in pursuit of art. If you're using an unfamiliar oven, you might want to keep a close watch on it the first couple of times because some parts of the oven might be way too hot while other levels are just right. You might get burning if it's in the wrong spot. On mine the stuff (including the paper) burns in five minutes on the bottom rack but is just right one notch higher.
Do a few test bakes on pieces that you don't care about to find the ideal temperature setting. I think everyone burns their first batch! I usually end up in the 250-275 range. Start low and gradually increase the temp to find the highest temp without burning. It will probably be different for each oven. It's good to conduct tests on light colors because these are the first to burn. To increase hardness and durability, it's better to increase the baking time than to increase the temp. I've read of baking times of several hours for some pieces but I usually do 45 min. and let the pieces cool slowly with the oven door closed. Most of my pieces are small. For larger ones (1/2 to 1" thick) I've baked for an hour with good results.
Paper is the best surface for baking on that I've tried. It will not burn at that temperature No sticking, no shiny spots like you get with aluminum foil. For very small pieces that might roll I fold the paper like an accordion. Any utensils or trays that you use with the clay should be permanently consigned to art use only (not food) just to be safe.
I hope these tips help prevent big messes and disasters! These are from one person's experience only and may not be the best or only way to do things. Please be safe! Make sure to read the directions on the clay package carefully.
For more information on all aspects of Polymer Clay work, I highly recommend the book "The New Clay" by Nan Roche.
Send e-mail to Carolyn Substitute.