Polymer clay doesn't shrink or expand.

What happens to polymer clay after baking?

The baking times and temperatures for baking polymer clay are crucial. If the temperature is too low, the clay will crumble. But if it's too hot, the outside will fuse and burn before the centre of the clay is cooked through. While baking, the clay should cure evenly throughout and turn into a hard plastic.

How long can polymer clay sit before baking?

It is suggested that thicker pieces be initially baked for 15 minutes, then another 5 minutes, another 5 minutes, etc. The clay needs at least 15 minutes to cure properly.