How do I determine optimal bake time for a polymer clay sculpture? When making polymer clay sculptures, I often end up with pieces of varying thickness (e.g. thin at the edges, thick in the middle). How do I select an appropriate baking time to avoid burning delicate details, but still ensuring thicker parts are solidified?

Is there a general formula, or do I have to rely on instinct -- "hmm, it's starting to smell really burnt, I should turn off the oven"?
If you burn your clay your oven is too hot. So turn down the heat a bit.
You can also put your creation into a box made from aluminium foil pans. This will protect it from direct heat.

You can also bake the clay multiple times. So create the bigger pieces first, bake them, add the details and bake everything again.

Another option is to bake everything separately and put it together using glue or even the varnish for small details.