This is an improved version of lemonie's Instructable Big explosion, bang, fireball, so hoorah to him for it. But any way, my idea is that I wanted to control the exact moment it went off, so this brought me to my first idea, just put black powder and a fuse in the lid of a butane can. Well this didn't work, I just got a jet of flame, plenty cool, but no fireball or musroom cloud. I realized I lacked the essential ingrediants of compression and rapid combustion. So I made this. It's literally a firing mortar for the can, the idea is a non-explosive shell (a coffee can filled with cement with a large bean can set inside to make an orofice) filled with an explosive, with the can of butane in the middle, and a cement stepping stone on top. The idea is that the explosive, when detonated, implodes the can, thus pressurizing it, then ignites the butane, thus decompressing it, A.K.A BOOM. The stepping stone by this point would have come of, thus allowing the expanding hot gasses to disperse. For saftey, the entire contraption would be put in hole in the ground, with no green grass growing all around. The reason I haven't tested it is that I had a very close shave with the cops for the butane can incendierary grenade. Disclaimer, I am not liable for what you do with this information, nor am I responsable for any damage to person or property, in other words, it's your problem if you kill your self. If you haven't yet noticed why this works like an A bomb, what in tarnation are you doing on this site? But, for credebility, I'll say. The main method of detonating a fission weapon is the implosion method. Prior to detonation a nuclear weapon consists of one or more pieces of weapon-grade fissionable material which are subcritical in configuration.The implosion method is when one sphere of material is compressed (through an explosion) to make it supercritical, which leads to a chain reaction, which results in the destruction of the atom, leading too duh, a big explosion.