I've posted this question on a FB forum, but thought I'd try here too...
I've made and packed a plaster pate de verre mould. It had undercuts in it so I've packed it with talc to stop it collapsing during firing.
My question is - how much to tweak the firing schedule to allow for the heat the talc absorbs. I know it needs a longer time to heat and cool - but how much longer? 20%? double? I can't find anything on Warm Glass or Morganica.
Advice appreciated, otherwise I'll just guess!
Thanks, Moira