Wired: Like every surfer, LeRoy Whinnery mourns December 5, 2005, as Blank Monday. That was the day Gordon “Grubby” Clark shut down Clark Foam - the world’s leading manufacturer of blanks, the foam cores for surfboards. But unlike other surfers, Whinnery knew of something that might replace Clark’s suddenly unavailable formula for supermalleable polyurethane. It just had to be adapted from a rather unusual application: nuclear warheads.