Step 4: Sculpting Your Masterpiece
I used a fine-toothed pull saw to carve the faces of the rock. It worked well because it was long enough to cut wide faces. Work your way across the entire mountain cutting off the rounded "lava-like" sections of spray foam. Be careful not to cut too deep -- you don't want the chicken wire to show through.
I cut horizontal and vertical ridges into the rock face to simulate a real mountain.