I've posted this in a game hobby forum as well. I'm repairing a house that had some fire damage, and as such I have a lot of drywall scraps. I am curious about the additives that can be expected, but my own searches obviously don't have the right key words.
My first experiment didn't pan out to well. I don't know if it was too hot or too many adulterants or what else may have contributed, but the result did not behave like plaster.