On Tue, 5 Feb 2013 09:49:59 -0700, "Steve B" wrote:

I want to make a noisemaker air tank cannon by cutting off a tall O2 bottle.
I don't want to fire any bowling balls, just create a loud boom for New
Year, and 4th of July. Would it be better to use gunpowder or Acetylene/O2
mixture? I am considering of using an inflatable 99 cent ball to block the
barrel, just charge it, insert the ball, inflate, and fire. Leave it
hanging on a rack when not in use, and call it a bell, in case anyone should
investigate the sound of the report.

Steve

Don't fire that sucker too close to the house! That volume of
Acetylene/O2 mix will create significant overpressure, could break
windows if too close.

Empirical data: ignition of a 30-quart kitchen garbage bag filled
with O2/ C2H2 mix didn't break any windows but it did knock garden
tools off the wall of a wooden yard barn that was maybe 50 feet away.
A tall O2 bottle will have aprroximately that volume of gas at
atmospheric pressure.

I would strongly suggest grounding everything while filling to
preclude static sparks, and then use electric (sparkplug or squib)
ignition.

A friend of mine actually did make a bell or gong out of a tall oxy
tank; cut the end off here at my house with my plasma cutter. When
struck with a bonger, it makes a very satisfying and
quite-long-lasting tone; it's a very high-Q resonator. Geez, if
twanged with a charge of O2/C2H2 the thing may ring for quite a while!