I use Kato polymer clay so they are baked at 130Celsius for at least ten minutes, I'm quite precise with the temperature as I've found that Kato can discolour or go shiny (not what I want) if the temperature is too high.
oh icic... i use scuply III and mine got either discolor or brittle 
, finally gave up and use grace clay
, finally gave up and use grace clayI've never used Grace before, how are you finding it?
i got mine online from tinkleartncrafts
Thanks I'll look into that 