Old TV screens are about 7/16" thick, watch out for the stuff in the tube. I break the tube with a .22 pistol, then carefully pick up the glass after it has been rained on several times. Get a painters' canvas drop cloth and knap on it, when you are finished, pick out the larger flakes, the fold it into 1/3'rds, the fold it in half, all the chips will go to the middle. Then take it over to a trash can and hold one end, the chips will fall out the other, a few shakes and you can fold it up until the next day. Bill