Originally Posted by willwren
And that match and gas tank idea worked. I found it. It was louder than I expected.
Okay, true story: I'm showing up for work one evening some years back at this local mega-church outfit that fixes up donated used cars for needy applicants, that kind of thing -- volunteer work once a week. So anyhow, there'* this gas tank sitting on the floor, all puffed up like a balloon. I asked what happened, and it seems that one of the other guys had the tank out of a car to fix a leak in it. So he did it the right way: filled the tank with water before he started welding or brazing or whatever, then drained the water when he was done, then filled it with alcohol and swished that around to clear out leftover water, then drained _that_, then left it overnight to dry.
So the next morning he comes in, looks at the tank and decides to do a teensy bit more welding on it. He figures it'* dry inside now, but forgets that it'* full of alcohol fumes. So he fires up the torch, starts in, and suddenly there'* this great big *FLONKKKK*
The tank blows out like a kernel of popcorn, pops itself off the bench and lands on the floor. It didn't tear itself open, so last time I saw it, they were trying to get it back in shape by sitting on it...