I was in high school in 1970 and building a trailer (for the cannon pictured below) with a high school friend in his Dad's shop. The shop was a long, skinny room in a daylight basement. The door led out into the yard at ground level and there were several windows along the length of the shop. Steve and I had been doing all sorts of things, on and off, for months in the shop, including some copper plating. There was an old bucket in the shop that was sort of a "slop" bucket used as a receptacle for whatever needed to be dumped. From the previous week, the slop bucket happened to be full of a fairly concentrated copper sulfate solution from our plating work. On this particular day, the slop bucket had migrated next to the bench that had a huge vise on the end. I had gently clamped an oxygen acetylene torch in the vise and lit it to use as a stationary heat source for heating and then bending a piece of steel for something on the trailer. At some point, the torch fell out of the vise and into the bucket. The flame went out but it took me a while to get the red hot iron bent and put down safely someplace so I wouldn't catch the shop on fire. All the while the torch was bubbling away in the bucket. I dropped the hot iron and turned off the gas.....and we were done for the day.
We didn't go back to work in the shop for a couple of weeks.....summer.....hot Southern California days. Everything was just as we had left it from weeks before. The door was open and Steve was standing in the doorway. I was a few steps further into the shop and had picked up a scrap piece of steel bar out in the yard. It was about 6 inches long and fairly heavy. When I got into the shop, I tossed the scrap a couple of feet into the now dry slop bucket. When it landed in the bucket, there was a terrific explosion that sent both Steve and I flying out the doorway. All of the windows of the shop were blown out as well. As we rolled around in the yard trying to figure out if we were dead or alive, we had no idea what had just happened......
??
It took us a while to figure it out, but we had inadvertently made copper acetylide....a very unstable contact explosive......in that slop bucket. When the torch fell into a bucket of copper sulfate solution (probably had a little muriatic acid in it as well) and the flame went out, the acetylene gas bubbling through the solution made dark brown clouds of of a muddy looking precipitate (we had noticed this at the time and didn't think much about it). When the bucket dried out over the intervening weeks, the now dry copper acetylide only needed a slight tap to set it off. Tossing the scrap steel into the bucket was more than enough to do it.
No one died, thank God......and we weren't even very injured. We did have to replace the windows for Steve's Dad and straighten up a lot of stuff in the shop that had been moved around by the blast. But we learned a valuable lesson....contrary to popular belief, what you don't know CAN hurt you.....
(P.S. Having now learned how to make copper acetylide, we refined the process and made a lot more of it over the next couple of years. It had all sorts of good uses for two high school boys...
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