While laying WS foam risers for subroadbed the other day I was searching for different objects in my garage to use for weight to hold the risers down while the glue dries. One of the items I used was a new can of that insulation foam in a can that you spray into holes and what not and it expands and hardens filling the hole. The thought occurred to me that maybe that stuff could be used in making mountains or in other areas where maybe just some filler is needed. Anyone ever use this stuff? Would it make a suitable mountain if you used it to build the mountain and then did some carving on it?? Seems like it would be tough and very lightweight.