A former colleague of mine
was, in one of his previous jobs, employed as a welder. In Ireland, very close to the border with Northern Ireland. He would have been sacked for this little stunt (if not imprisoned) had he been found out.

One of his favourite tricks was to fill an empty crisp bag with oxygen and acetylene, put it on a piece of newspaper, light the paper and shove it in below the cubicle door when someone was having a crap. The victim would instinctively stamp on it to put it out, which of course expelled the gas and caused it to explode. Much hilarity ensued from seeing the innocent crapper emerging shellshocked from the cubicle.

Anyway, one day, said mate and his colleagues decided to scale up the experiment. They got a big black bin bag, and filled it with an explosive oxygen/acetylene mix, sealed the end with tape and took it off over a field into a ditch. They placed a "fuse" of newpaper, lit the end and ran like hell. 100m or so away, they sat, hiding below a piece of sheet steel.

Several minutes passed.

Eventually, they decided the paper had gone out and went to approach the device. Major error - never go back to a firework once lit, children. They had fortunately only gone a few feet before it went off.

He described the effect, which occurred in a fraction of a second, of the hedge by the ditch suddenly going from green leaves to nothing, and a ripple in the grass as the shock wave made its way over the field. Then BOOOOMM!

They legged it back to work.

Seconds later there were police sirens and blue lights everywhere. As there was no evidence of any explosion, save for the mutilated hedge, they were never caught. But apparently when the heat was off, they'd gone back to the scene and found no evidence of the bin bag, just a bare earth crater where the grass had been blown away, and a large amount of slimy green mush, which was the foliage which had been blown off the hedge.

Must have been quite spectacular.
( K2k6 has a proper job these days, Wed 15 Aug 2007, 10:06, Reply)