Ted, at one job years ago, my co-worker filled a heavy black 55 gallon trash liner with acetylene, and a splash of oxygen for good measure. The igniter was a flashlight bulb that had the glass broken with pliers. He soldered about 100 feet of two conductor wire to the bulb, and taped that inside the filled bag. He set it outside the plant, and used a 6 volt lantern battery to light the exposed filament from inside the building. You would have thought a gasoline tanker had exploded from the sound of it, and it shook dust off of the trusses.
I saw the aftermath of a slightly smaller version of acetylene in a trash liner. It ripped a steel commercial man-door off the hinges and bent it badly. That was a practical joke that went a bit overboard, and the millwright who did it told me he thought he was permanently deafened afterward. It would be a great noisemaker for the Fourth of July, but with a plastic bag containing something that explosive, I kinda worry about static electricity setting it off while taping it closed. At very least, I'd expect ruptured eardrums from the concussion.
