Kind of a newbie question, but I'm looking for something to build up the base of a diorama (building up some small hills, etc). I've used joint compound for really small bases before, but if you go too big with it, the stuff starts cracking and coming off in chunks pretty bad. I'm starting a big diorama (about 2 foot square) so I need something else. Is celluclay good for this?
Thanks and sorry for the remedial question

John