Since I began making dolls, I've frequently been asked questions regarding what kind of polymer clay, tools and materials I use. Your choice of clay should be your first consideration. My favorite is Sculpey's® "Living Doll."
Your choice of a polymer clay should involve some research into its sculptability, how it bakes and what its properties are. When I first started working with polymer clay and sculpted my first doll, I was afraid to put it in the oven and have it burn up. I believe everybody would be worried about this on her/his first time sculpting, am I right?
So I wouldn't risk my hard work, I felt it would be wise to make some cylinders to be baked at different temperatures and times and see what happened to them. This way there was no risk of spoiling my doll. Once the cylinders were baked, I observed how they behaved regarding twisting, traction and how colour shades changed according to temperatures.
It was my conclusion that polymer clay manufacturers have a good reason to give the directions they do about oven temperature and baking times.
According to my own trials, the manufacturers' directions are the most suitable. This is why, when someone says to me that she/he bakes her/his clay with the oven barely heated, or with any temperature lower than 130ºC (thinking that the piece might be burnt at a higher temperature), or at a higher temperature in order to finish quicker, I always advise them to closely follow the manufacturer's directions instead.