This is a good question,,,,,as a kid ,, me and my bro's built many bombs,,,not a one exploded in our face's,,,started out with 500,000 match heads packed into paper towel tube's,,,,went "boom",,,,then moved "up" to unrolling seven brick's of firecracker's and packing them into paper towel tubes,,,went "BOOM",,,,did you know "HTH" pool chemicals blow up packed some in paper towel tubes,,,oh man,,big "blue" toxic "BA-BOOOM" 100ft blue cloud floating over the neighborhood,danger,danger ,,then came keg's of black powder,,,went boom like a hand grenade, complete with a "crater" in the ground,,,Jesus well that stopped when my friend Andy whilst playing around , burned his face off when the scab fell off we all called him "paleface" and "Spock",,, ,,,pretty "white",,,,,,,,,whiter than Jonney Winter,,,,then another friend found "The BOMB" while shopping at a local "Agway" farm store ((we were farmers), available to farmers was the equivilent to C4 satchel charges, meant to be used to blow stumps out of the ground,,,complete with a plunger, wire , the works set one off behind a local "pub" around last call one night,, took down a 30ft concrete wall it was planted behind,,,emptied the bar right out as well ,,WTF blew up jesus where's the wall no one was injured,,,,Jesus these day's all thats available to "farmers" is good old super phosphate,,,packed in a paper towel tube,,,,still enough to take small tree's down and roll the fat lady over several time's,,,,we were lucky we didn't get burned,, other than "paleface" of course,,,,all of this was carried out when we were "wasted,,stoned,,and drunk",,, all these bomb's, plus riding street bike's as fast as you could go down a 13ft wide cow path without hitting a tree or big rock or something,,,Jesus ,,lucky to be here man