[TheForge] Volume of a #4 acetylene cylinder?

[Keporter at aol.com]

Acytelene is sold by the cubic foot. It isn't practical to sell it by the  
pound or by the gallon, because it must be stored under pressure within acetone, 
 which itself is contained in a special bottle that is filled with a padding  
material to ensure against shock. The acetylene is stored at about 400 PSI, 
but  cannot bubble out of the acetone very fast; thus partially full containers 
are  often sent in to be filled. So, in order to manage the situation, 
acetylene is  sold by the cubic foot, and how many cubic feet are being compressed 
into the  bottle is kept track of during filling--anyway, that's the theory :-) 
Unless you  plan to weigh your bottle before and after every filling, you 
kind of have  little choice but to trust your dealer; nice huh? Most people, who 
don't use  their torch for steel welding, are switching to propylene, which is 
nearly as  hot, and about half the price to run, even with increased oxygen 
consumption  figured in.
Mike P.