The pressure for those soda kegs comes from a co2 tank just like the ones we buy for aquariums. The kegs themselves can hold some pressure, but the walls are thin. A lot of people use those kegs for homebrewing, and to get carbonated beer via this method they apply something in the neighborhood of 20 psi from their co2 tank. The co2 is in dissolved gas form and isn't very much volumewise. A soda keg full of soda, not hooked to a co2 tank, is flat. I don't think they could hold alot of pressure due to their large area and thin walls. 150 psi over 4 square (that would be a tank .6 feet in diameter, and 2 feet tall) feet is 86,400 lbs pushing on the insides of a tank. If you hook a regulator to a container like this, and it doesnt bleed off fast enough, well... I'm sure you can see where this could lead to problems. I can't remember if they have a safety valve or not, but they probably do. I'm not saying it would rupture, but I would be very nervous myself.
Last edited by Sharkfood; 06-22-2010 at 02:17 AM.
Reason: math was off