"Hmmm, isn't Plaster of Paris used (with gauze) to make plaster casts? eg for broken limbs and similar"
As I recall, it's applied one thin layer at a time, in strips. There's plenty of time (and surface area) to cool things off between layers.
A heat insulated microwave packed with the stuff all in one go will be a different matter.
Biting the hand that feeds IT
