Co2 Pressure 12g / Lge Bottles

Nearing completion of my rig, for running a QB78 from UK Soda Stream re-fillable bottles, via special home designed adaptor & std paintball hose.

A thought that has crossed my mind during the process is about pressure.

What pressure occurs in the 78's gas tube when it is filled from two 12g bulbs ?

What pressure are the 12g bulbs filled to ?

What pressure would a paintball bottle get filled to ?

I think i read somewhere that a pressure gauge on a Co2 bulk fill kit is somewhat superfluous ? Is that the case ?

Answers on a postcard to....... that damn Englishman Again !!

Thanks All

[SDale]

Generally CO2 pressure is the same reguardless of the volume in the tank.

Usually around 850-900 psi at 70-75* F  ambient temp. You could get as much as 1200, but you'd have to paint the bottle Black and leave it out in the summer sun for a few hours.

[ribbonstone]

that's the nice thing about c02...a thimble full or a train tanker car full, it's all going to have the same pressure if at the same temperature; container volume has little to do with it.  Typically, 12gr. or 20oz. paintball tank, are filled to about 70-75% of the available volume.  As you shoot, use some of the pressurized gas in the "empty" part of a tank...and automatically, some of the liquid CO2 converts to gas to keep the pressure the same.

Pressure is related to temperature...but the tank tries as hard as it can to keep pressure equal all the time, converting liquid co2 to gas co2 as you tap out a little "puff" to push a pellet, keeping pretty much at a stable pressure so long as there is liquid co2 in the tank.

So relax...if you hooked your remote line to the top of a tanker truck, would get the same pressure at the base of the pellet as you would hooked to a 12gr. cartridge.