Baking polymer clay sculptures in the oven
One of the best properties for polymer clay is that a kiln is not necessary to cure the clay. Polymer clay can be baked at low temperatures and the household oven or toaster oven is all that you need.
I predominately use Super Sculpey so the instructions below will use Super Sculpey for the example. However, no matter what clay you use, you should be able to see baking instructions for it on the box or container that the clay came in.
Super Sculpey’s instructions recommend baking your sculpture at 275 degrees for 15 minutes for every ¼ of an inch in thickness. If you have a sculpture that is over ¼ an inch thick then I would recommend either backing the sculpture in stages or lowering the temperature and baking the sculpture for a longer period of time. My personal preference is to bake my sculptures for a longer period of time at lower temperatures. I’ll put my sculpture in the oven at around 200 degrees and let it sit while the oven heats up to around 230 – 250 degrees. I will then bake it at that temperature for about 30 minutes. This process has worked well for me but you may want to test with a sketch piece before baking a finished piece.
Another great property for baking polymer clay is that you can bake it multiple times so that you can work on your sculpture at different stages. To bake and re-bake your sculpture you will need to use Vaseline.First of all, you will need to bake your sculpture and let it sit for awhile to cool down. After your sculpture has completely cooled down, could take several hours depending on the size of the sculpture, you will need to lightly coat the baked sculpture with Vaseline. I recommend using a paint brush to apply the Vaseline but your finger should also work. After the Vaseline has been applied you will then wipe it down with a paper towel or rag.
The next step is to apply a thin layer of clay on top of the Vaseline to adhere the clay to the baked sculpture. This should give you a sticky enough area to begin sculpting on top of the baked area. There are no limits to how many times you can bake the sculpture so just repeat the steps above if you need to bake the sculpture again.