Pump + X-valve + CO2 = ok?

[mr doo doo]

I'm currently using a classic valve in my pump, but want to use my X-valve instead so i can use the classic for something else. I hear CO2 (from a 12 gram) would be ok with a X-valve since the ROF will be extremely low. is that true? what bad can CO2 do to an X-valve anyways?

Thanks

[questionful]

It would not be okay. What you can do is deactivate the RT reg by removing the reg seat or something (perfectly safe as the pressure relief would still be in there) and use a Stabilizer as a foregrip or something. I got the idea from aqua_scummm, he made a post about it on SO.

http://forum.specialopspaintball.com/index.php?showtopic=149981

[rawbutter]

I'm not sure I agree. The only problem with CO2 is the liquid, and I don't think there's liquid in 12grams.

I've used CO2 in an x-valve (with a remote) before with no problems besides shootdown. As long as you don't get liquid in the valve, you should be fine.

[mr doo doo]

I'm not sure I agree. The only problem with CO2 is the liquid, and I don't think there's liquid in 12grams.

I've used CO2 in an x-valve (with a remote) before with no problems besides shootdown. As long as you don't get liquid in the valve, you should be fine.

cool, that is what i was thinking about: the liquid part. i mean, RRFireblade uses 12 grams on his pump, so i was sort of assuming it would be fine since 12 grams doesnt carry much liquid inside.

[Smoothice]

cool, that is what i was thinking about: the liquid part. i mean, RRFireblade uses 12 grams on his pump, so i was sort of assuming it would be fine since 12 grams doesnt carry much liquid inside.

supposedly rrfireblade has done quite a bit of modification to his xvalves. I'm not sure if that is to make them work on 12'ies or to increase the efficiency.

[Spencer]

I'm not sure I agree. The only problem with CO2 is the liquid, and I don't think there's liquid in 12grams. .

Nope, there has to be liquid in a 12gram, other wise you wouldn't get much less shots off the thing.. If you compress co2 past a certain point it becomes a liquid. And the pressure inside 12 grams reaches up to 1200 psi.. Also isn't it 12 grams of liquid co2 in them?

[mr doo doo]

supposedly rrfireblade has done quite a bit of modification to his xvalves. I'm not sure if that is to make them work on 12'ies or to increase the efficiency.

i thought he modded his x-valve to increase efficiency since he got like 25 shots of a 12 gram. on my classic, i only get 15 ...

[Spider-TW]

Nope, there has to be liquid in a 12gram, other wise you wouldn't get much less shots off the thing.. If you compress co2 past a certain point it becomes a liquid. And the pressure inside 12 grams reaches up to 1200 psi.. Also isn't it 12 grams of liquid co2 in them?

You're probably looking at the burst pressure of a 12 gram. There's 12 grams of CO2 in the cartridge, less than half an ounce (28.3 g). Normally, that 12 grams should be mostly liquid in there, just a long ways from being full. How much liquid depends on the temperature.

At about 75 degrees Fahrenheit, CO2 vapor pressure is about 750 psi. If the volume goes down, the CO2 vapor condenses, reducing the volume of vapor. If the volume goes up, the CO2 liquid vaporizes to fill the volume up to the vapor pressure. The pressure stays the same as long as there is some liquid left to vaporize or if there is vapor to condense. That all assumes the temperature is allowed balance out. That's why fixed HPA systems tend to be set around 800 psi. Air doesn't quite expand as much as CO2 in common marker conditions and it takes a little more pressure to get similar final volumes with air.

If you raise the temperature, the CO2 liquid will vaporize first and then the pressure will start going up much faster. Kind of like boiling water on the liquid side, but the curve is different and the vapors are very different between the two.

It would be the best thing in the world except that the CO2 absorbs a lot of heat to vaporize, cooling off the whole volume and effectively lowering the vapor pressure, sometimes to the point that the vapor under pressure will re-condense. which messes up your pressure, density and velocity.

[athomas]

Its the condensation that causes problems with CO2. The retro valves charge fast enough to chill the C02 leaving the tank and generate heat when it recompresses in the chamber. The change in temp causes condensation issues which allows pressure spikes and orings that don't seal properly due to freezing.

[mr doo doo]

basically, i shouldnt do it then unless the temperature outside is hot?

[Nick E]

NO.
Basically, you shouldn't do it at all, unless you disable the special regulator. The regulator "slam fills" the chamber, causing the c02 to condense into liquid(what athomas was talking about), screwing things up. You could take out the reg piston and just use a side mounted stab or whatever, which would work.

[mr doo doo]

ah, haha, ok ok. i always get confused when someone talks science and whatnot. dont want to run a stabilizer since it will just be too much money and stuff. so i guess 12 grams is a no no... thanks guys.