alternative to a co2 regulator?

[Lockednloaded]

I have a CO2 tank and an adaptor, but I don't really want to spend money in a regulator, so I thought a good way to get around that would be with a pre-calculated expansion tank. I could have a small high pressure expansion tank with a gauge, and with some simple math, I could calculate how big that expansion chamber has to be to fill my gun to a certain pressure. For safety, I would mount a pop-off on my chamber in case I mis-calculate anything.

Would this work? I feel like this would be especially useful to aussies because they can't order paintball parts

[ramses]

That does work, but you'll need a rather large expansion tank. I was doing a calculation recently, and I found that at 60* F, 20oz of CO2 will expand to 10 gallons at 110 PSI. The pressure is also very temperature dependent, and the tank will get really cold, as will the expansion chamber

Wolfram Alpha can be quite helpful with this stuff. Simply type in Volume of _____ oz of CO2, ________ units of at _______ pressure and it will usually give you an answer.

[PVC Arsenal 17]

CO2 is terribly inconsistent, even with a good regulator like the one I use. Yes this can be done, but don't always expect to get the results you want. Definitely make use of a pop-off valve.

[saefroch]

CO2 is terribly inconsistent, even with a good regulator like the one I use.

I'd say it's not the CO2 but the regulator you're using. A very precise regulator is hard to come by, which is why a lot of the hybrids on this site use manometric fueling, instead of volumetric.

In reality, a mechanical regulator is probably subject to all sorts of error, where a electronically controlled regulator would be far superior .

[Hubb]

The best CO2 reg I've used is a Palmer's Stabilizer. A new one can be bought for less than $70.

About your idea, it works. I've used it on a few different designs. The 800+ psi would fill a small chamber then I'd close it off from the tank. From there, I'd dump the expansion chamber into a larger one, and it would put the pressure around 100 psi or whatever. I just used the simple P1V1=P2V2 calculation and, although it wasn't exact, it did work as I intended it to.

[Lockednloaded]

I don't need a precise regulator, so I think this will be fine for my purposes as long as its accurate to ±10psi