How much PSI?

[Shazaam]

How many PSI are 12 oz C02 tanks suppose to hold? It doesn't say on my tank.

[LordChaos]

Internal pressure on all CO2 tanks (regardless of size) is a function of the ambiant temperature and amount of CO2 in it. Normaly, at room temp, it should be ~800 psi or so IIRC (though it's been a few years, so you might want to check).

[UTLadiesMan]

At room temperature, CO2 turns into a liquid at about 850 psi. So if it's half liquid, half gas, the pressure of the gas is 850 psi. Pump more CO2 in there, and the pressure of the gas is 850 psi. Shoot out a lot of CO2 and the pressure is 850 psi. If you shoot to where there is no longer liquid, you will then be under 850 psi. If you fill until there is no longer gas, you will be above 850 psi and might destroy your tank. Of course, as the temperature rises, it takes more and more pressure to liquify CO2, and the opposite for lower temperatures.

[LordChaos]

Originally posted by UTLadiesMan
At room temperature, CO2 turns into a liquid at about 850 psi

I knew it was in the 800's.

Also, IIRC, a typical CO2 fill puts the tank at 2/3 liquid and 1/3 gas.