Thanks, David P. You've given me a great deal to think about and research. Will definitely look up these products. All I really want to do is cover over with something I can carve paint and seal. Hope these products work. Thanks again.
I create weird and unique waterfalls and fountains that are partly submerged. I need a product that will waterproof painted polystyrene or Plaster of Paris. Permanently. Anyone know of such a product?