Nitrogen Vs CO2 OBA

I've been looking around, but can't find much information about Nitrogen OBA systems. I'm wanting to know the difference between the two, why run one and not the other, pros and cons of both systems....pretty much anything. I know Nitrogen is more expensive than Co2, but I'm not worried about it; we have a nitrogen farm at work. Any info would be appreciated. Also, do you need to run a gas sticker on your rig if you run Nitrogen or CO2? I know all the transport trucks do and I figured it might be something that would be required, but I've never seen it around.

From what I know of my paintball days, the biggest difference between the two is performance in cold temps. CO2 output at least on a paintball cylinder is around 800psi at 70 degrees F. But drop the temperature, drop the bottle pressure. Drop it enough, you can be outputing liquid CO2, whcih Im assuming is not good for tires. But nitrogen remains constant at the normal temperature range you would experience.

Another difference if your running air tools, is CO2 tends to be a dirty gas, lots of dirt/rust particles in the fill. Def. Want to filter that stuff.

From what I've been reading and such, you can use the same tanks for CO2 and N2, just not the same regulators. Does that sound correct?

98, that's some good info to know. I know that co2 produces liquid when used at high rates, but other than that, I just know guys use it on the trail a lot.

I was under the impression that the tanks are different. Also PowerTank makes an adaptor to mount their regulator on a N2 tank.

(1) tank of CO2 is equivalent to (3) tanks of N2. CO2 is a dirtier gas but can still be run in air tools just fine but you need to keep them oiled properly. I believe it's even dry enough to run through a paint gun.

I believe the main difference is that N2 is almost completely dry and a much cleaner gas. But who cares for tires. As for pressure, I've ran my tank at Tellico the last 2 trips and the outside temp was around 25 degrees, no problems at all....

But if you get N2 for free there isnt any reason not to use it.

Would you need to run a placard on your rig if you run CO2 or N2? Are there any laws concerning that style of OBA? I've read the state laws, but can't find anything, but I'm thinking mainly DOT laws.

53guy said:

Would you need to run a placard on your rig if you run CO2 or N2? Are there any laws concerning that style of OBA? I've read the state laws, but can't find anything, but I'm thinking mainly DOT laws.

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that one would be up to the cop that pulled you over and the mood he/she was in
i dont see any reason to run the plac. but i could be wrong ive just never heard of anyone having too

http://www.paintballguns.net/co2-vs-hpa.php

A quick comparison of the two, remove paintball marker and insert air tool and it should apply the same.

I have a nitrogen tank I originally bought to adjust the pressure of my shocks. I had no idea you could use it in tires until someone told me they use it in NASCAR. Then I started seeing a tire store in the area advertising nitrogen fill ups. I have been using my 20cf tank to air up for the past year and it works for me. However the tank dose not last nearly as long as Co2. I would estimate about 5 fill ups (x 4 35" tires) from 15psi up to 32. I would still like to get a Co2 tank too for air tools.

On my last trip, my 10lb Co2 tank had enough in it to remove/install 24 tires with the impact wrench (taking off a rim counts as 1, putting on a rim counts as another 1), fill up mine and my buddy's tires for the weekend, re-seat one bead, and blow off some of that evil dust that Rockport is known for. Oh, and it cost under $100 for the used tank with new fixed regulator and I think it's like $15 to refill. Dirty or not, I love it.
Jeep on!
--Pete

I think I'll probably run N2 for a while until I can find a place to refill co2 around me. Everyone just wants to swap bottles and I'd rather not get rid of my aluminum one.

I get my Co2 from a local welding supply shop. No exchanges there, just refills. Check your phone book or google to see if there's anything near you that has eluded your radar.
Jeep on!
--Pete

There has been some miss information here so I will try to give the correct facts. Nitrogen works great in tires, so does CO2.

CO2 is not dirty. It does have some moisture in it but that isn't normally a problem.

CO2 tanks and nitrogen tanks are usually different since the nitrogen is held at a much higher pressure (around 3000psi). You could use a nitrogen tank for CO2 but not necessarily the other way around.

CO2 holds more cubic feet because CO2 is in a liquid state in the bottle at its normal pressure around 800psi. As you use the gas off the top, the CO2 boils and generates more CO2 gas. This causes the bottle to get cold as you use it. If you use it real fast, you can actually get to the point where the CO2 actually starts to freeze in the bottle and will limit the available flow rate.

Regulators for CO2 and nitrogen are of different ratings and are normally not interchangable.

You can get a CO2 tank that is made from aluminum, but nitrogen tanks will not be aluminum.

Aluminum tanks are normally painted with a special clear coat. It is designed to change color if the tank is exposed to elevated temps. They had a lot of problems with people powder coating the aluminum tanks, which changes the aluminums properties. A lot of tanks exploded when being filled. My local refillers will not fill a bottle that has been painted.

old_man said:

CO2 is not dirty. It does have some moisture in it but that isn't normally a problem.

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From what Ive read it's not that the gas is dirty, but due to the moisture and general fact that it doesn't matter as much for CO2, the tanks themselves are usually dirtier on the inside. If on airtools you should oil and filter anyways its cheap insurance.

old_man said:

You could use a nitrogen tank for CO2 but not necessarily the other way around .

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True again, it's the regulator that makes the difference as to if this will work, some reg seals don't like CO2 especially liquid.

old_man said:

CO2 holds more cubic feet because CO2 is in a liquid state in the bottle at its normal pressure around 800psi. As you use the gas off the top, the CO2 boils and generates more CO2 gas. This causes the bottle to get cold as you use it. If you use it real fast, you can actually get to the point where the CO2 actually starts to freeze in the bottle and will limit the available flow rate.

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He's on a roll with the facts. Note that it will not only freeze in the bottle, but will freeze the tools you are using, sometimes causing damage. Was common in my paintball days, not sure how air tools would handle it. Also can give you a nice case of frostbite if you are holding on to the bottle at the time.

old_man said:

Aluminum tanks are normally painted with a special clear coat. It is designed to change color if the tank is exposed to elevated temps. They had a lot of problems with people powder coating the aluminum tanks, which changes the aluminums properties. A lot of tanks exploded when being filled. My local refillers will not fill a bottle that has been painted.

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Something I haven't seen mentioned but I might as well throw it out there. At least here, after a certain size limit, a tank of either usage needs to be hydro tested I believe 5 years after the stamped date on the tank. Usually stamped on the metal CO2 tanks and inlaid in the resin of the carbon fibre of the HPA tanks. Otherwise it is illegal to fill them if they are past that "expiration" date. They will usually not be filled if there are "aftermarket" stickers, paint or annodizing as previously mentioned.

Race cars use nitrogen because the pressure stays more constant with temp change. The molecules of nitrogen are larger than air mix and over a long time period tires will stay inflated longer. Be good for people that dont check pressure often. This is why you are seeing more nitrogen tanks but I don't see any advantage for what we need compresed air/gas for. Some tire stores are offering nitrogen fill for you tires.

98XJSport said:

From what Ive read it's not that the gas is dirty, but due to the moisture and general fact that it doesn't matter as much for CO2, the tanks themselves are usually dirtier on the inside. If on airtools you should oil and filter anyways its cheap insurance.


True again, it's the regulator that makes the difference as to if this will work, some reg seals don't like CO2 especially liquid.

He's on a roll with the facts. Note that it will not only freeze in the bottle, but will freeze the tools you are using, sometimes causing damage. Was common in my paintball days, not sure how air tools would handle it. Also can give you a nice case of frostbite if you are holding on to the bottle at the time.

Something I haven't seen mentioned but I might as well throw it out there. At least here, after a certain size limit, a tank of either usage needs to be hydro tested I believe 5 years after the stamped date on the tank. Usually stamped on the metal CO2 tanks and inlaid in the resin of the carbon fibre of the HPA tanks. Otherwise it is illegal to fill them if they are past that "expiration" date. They will usually not be filled if there are "aftermarket" stickers, paint or annodizing as previously mentioned.

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Few Things:

1. Air tools will be fine as long as they are oiled properly, operating at the correct psi, and are a decent distance down the coiled hose (the gas has time to "warm" up).

2. Liquid CO2 doesnt boil in the tank it evaporates and that's what regenerates the constant pressure.

3. Most reg's are not interchangeable but if you go with a PowerTank setup their new reg is.

4. I have never seen my 10lb bottle freeze and I used it continuiously one time until it was empty. The reg. stands a good chance of freezing unless you have a nice high flow one. The only thing I have seen freeze on my PowerTanks is the brass coupler that goes from the reg. to the coiled hose.

I have a homemade CO2 setup and I have had mine freeze to where the safety pressure went off. Scared the piss out of me. If I keep using it, I probably will got to powertank or similar regulator. I have also had my hose freeze. I usually just wait 5min or so and let it warm back up and start using it again.

uncc civilengineer said:

2. Liquid CO2 doesnt boil in the tank it evaporates and that's what regenerates the constant pressure.

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I believe the thermodynamics term for when a liquid transistions to a gas is called the boiling point not the evaporation point. It is boiling due to the change in pressure, not due to heat. But the change in pressure, and hence the transition to gas requires energy which is pulled from it's surroundings. The pull of energy is what causes it to cool the tank, fittings, etc.

http://en.wikipedia.org/wiki/Boiling_point

smithz said:

I believe the thermodynamics term for when a liquid transistions to a gas is called the boiling point not the evaporation point. It is boiling due to the change in pressure, not due to heat. But the change in pressure, and hence the transition to gas requires energy which is pulled from it's surroundings. The pull of energy is what causes it to cool the tank, fittings, etc.

http://en.wikipedia.org/wiki/Boiling_point

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Thanks for that. I was wondering if anybody would catch that. Evaporation also has to do with a liquid turning to gas then being dispersed within the surrounding gas/atmosphere. Who said I was a pain in the ass engineer was probably right:yap:

Nitrogen is expensive, if you using it constanly i would go with co2

old_man said:

Thanks for that. I was wondering if anybody would catch that. Evaporation also has to do with a liquid turning to gas then being dispersed within the surrounding gas/atmosphere. Who said I was a pain in the ass engineer was probably right:yap:

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I'm a EE, but remember a few things from my thermo class.

In case anyone cares, that sudden lowering in pressure is the same reason a can of pop cools slightly when you crack it open.