After looking at T. Alexander's OUTSTANDING!! rockwork in his thread "Styrofoam Rockwork", ( http://www.the-gauge.com/forums/showthread.php?s=&threadid=3279 ) I have a couple of questions about the expanding spray-foam mentioned briefly in that thread. Firstly, Is there any advantage to using this over using styrofoam? I'm thinking about the advantages of filling "nooks and crannies"... would it be possible to simply fill those with painted bits of styrofoam? Secondly, Would the expanding foam adhere to a styrofoam base? Will it "eat" certain types of styrofoam? And lastly, Is it easier,more difficult, or about the same to carve as styrofoam? I'd like really appreciate anyone's input. Thanks!