Through the Answers section here, I learned of mixing borax, rebake into powder, and then mix alum to create a high polishable cast...and also read discussion of the use of horse hair or fiberglass fibers from insulation for reinforcing the plaster. Unfortunately, I haven't ever found enough details to test either of these methods. The other day at the store, my wife asked if tinsel would work. It never occurred to me, but it sounds like it would make sense. Have you ever tried to pull a strand of that stuff a part? Also, I'm sure right after Christmas, it would be dirt cheap and in vast supply. I have been using the plaster of paris for making mold for some Sugru/Oogoo projects. Anyone ever try this or have any suggestions? Or if anyone knowledge about the fiberglass thing that I can use as basis, that would be cool too. Also, I know there are better materials than plaster of paris, that are stronger and all, but I am trying to at least use what I have on hand first, and I know other people would find it useful too.