hi Chris Actually it is 6 layers of hd foil glued together and crumpled to resemble the blasted tunnel look. painted grey primer then weathered with soot and black. Thanks for looking Tom
Pretty good! Looks a lot like the old b/w photos of the tunnels blasted by the Central Pacific in the Sierra Nevada. Your technique looks much easier than hand-drilling and going through obscene amounts of gunpowder each day!
