I'm trying to make a mold of the chassis of a Furby so that I can slap some sculpey on there and bake it without it losing shape. I had the two halves all wrapped up, put plaster on them and they came out relatively fine. However when I poured the plaster for the cast in it fused itself to the mold and I spent a good 4 hours making a big chunk of plaster.
How can I avoid this? I'd also appreciate it if you could give me some beginner's tips so this sort of thing doesn't happen again.