Does CO2 work well?

[radiorobwalker]

I love my CO2. I used it on the trail not long ago to air my tires up and help out a friend who couldn't figure out how to make his fancy new Warn Powerplant winch/compressor work.

I "rolled my own" CO2 set up. A 10# CO2 tank, fixed flow regulator, hoses, mounting bracket, air chuck and all the other little goodies I needed/wanted cost me under $200.

And yes, I can use an air ratchet with it.

[Hindsight]

SkyKing previously said:

CO2 sounds like it will save me a lot of install work and thats real nice for me. Also, a lot less parts to fail on the road (or off).
If CO2 is okay to use, has anyone put nitrogen tanks in a truck. If ya fill your tires with it, the pressure should not change when its goes from hot to cold outside. Would think it would also work air tools (at about 1000 psi over CO2).

$.02 on this?

I have a nitrogen tank that I used until I had onboard air for my TJ. Running out has never been an issue unless I am really pushing the air tools. Cheap and Easy refills and the welding shop will do exchanges (important when you live in the semi-boonies). I have used it on all forms of vehicles...only really important with tires that you want to maintain a constant pressure in with heat buildup (I'm not sure how CO2 reacts with heat).

IMO: If you don't have onboard air...a tank is an important accessory!

Doc

[greywolf]

uphill previously said:

I made a choice to run CO2 instead of a compressor for these reasons:

• CO2 inflates the tires much more quickly than an air compressor does.
• CO2 runs my air tools. Why air tools? Because if you're going to do a front axle swap on the trail or going to do do some hard core repairs, many of the OEM torque specifications are considerable and good luck getting the 35MM axle nut off. You can't run air tools with an onboard compressor.
• I store the Power Tank on the rack on top. Yes, I could put a compressor in the engine compartment. Not a bad choice, but the engine compartment is essentially "full" at the moment. The MAF auxiliary fuel tank will be going between the rear axle and the rear bumper - so it would need to go inside and space is an issue.

So that's why. I think that the acid concerns are a non-starter. People have been using CO2 for a LONG TIME NOW with no difficulties - which is also my experience.

There are downsides to CO2

• There are recurring costs to tank fills where an air compressor is a one-time purchase.
• Weight - my complete load out on CO2 for a long trip is 30 pounds (1x10 lbs PowerTank and 1x20 lbs PowerTank). Usually I opt for one or the other but I do have two. If I anticipate a very difficult trail repair where I'll be running the air ratchet, I bring extra CO2.
• Most importantly, CO2 runs out and the compressor doesn't. For very long term expedition use there is a trade off between the potential need for air tools and the longevity of supply from a compressor.

Thanks Uphill,

That was a extremely good explanation of the pros & cons of Co2 systems.

Cheers.

[Radio]

Yeah, but a 10 pound CO2 tank just fills the pontoons on my boat! LOL... those suckers take ALOT of volume to fill!

[FJD08SE]

I've had my PowerTank for a couple of years now, and no problems. Never heard of the acid issue. In addition to Uphill's list, I would add that a 10lb tank like mine will fill somewhere around 70 passenger tires. That's a LOT of capacity. I have never run out, even after filling tires for 3 other trucks. One thing though - don't forget to carry gloves; the brass parts get COLD.

[bedu bandit]

Anybody have any idea if a CO2 tank would be ok inside the vehicle in hot (read VERY hot!) conditions. Does the CO2 expand in heat?
Would it be risky inside the vehicle?

Apologies for the hi jack - hopefully its an extension of the original topic

[FJ FunJunkie]

Bellydoc wisdom from a simaler post yesterday.
SkyKing previously said:
After doing my homework, I now understand that CO2 will work, but is and has been a bad idea from day one. It is called carbonic acid, and it will help the UV from the sun kill your tires. It is also real bad for aluminum, so it does hurt you air tools as well.
I have found that nitrogen is just about the exact opposite. Nitrogen won't expand or contract with hot and cold temps (CO2 is off the charts on that), and it has no acid gases...
I can't wait to get my nitrogen tank installed in the back. The can of nitrogen also has about 3 times the pressure (of CO2), so it will last a lot longer.
I started to look at this stuff when I got into paint ball guns. The change is like night and day...
The topic of nitrogen v CO2 has come up on this forum a few times, but the chemistry has still not caught on...

Bellydoc said,

Sorry to hijack, but there's way too much here for me to not make a comment.

First, "carbonic acid" is CO2 dissolved in water, it's not a gas. It's a very very weak acid, but the pH is less than 7, so it is indeed an acid. The formation and storage of compressed gas is an extremely dry process, so you're not introducing new moisture to mix with the CO2 when you fill. In fact, the corrosive effect of compressed air from a compressor is MUCH MUCH worse because it compresses atmospheric moisture and environmental (21%) oxygen. If you have a compressor with a volume tank, you'll note the water and rust that blow out of the drain hole every time you bleed off the pressure. Pure CO2 is not oxidative in that way.

There is no relationship between what is inside the tire and what happens to the tire from the outside with UV light or any other wavelength. The gas isn't diffusing out. The light isn't penetrating in. Neither CO2 or nitrogen gas have any special property with regard to diffusing into rubber. UV light has no special energetic capacity to penetrate opaque surfaces. Even x-ray light (which is far more energetic than UV) is significantly filtered by thick rubber.

I'm not sure why you say that CO2 is bad for aluminum either. The 10 pound bottle size is aluminum. The US DOT approves it's use. It works just fine and it has no service life issues.

Although the odd nature of CO2 is interesting at high pressures (it has properties that are different than those described in the "ideal gas law"), it has no significant pressure/volume differences in the tens of PSI over atmospheric pressure that we use to fill tires. At these pressures, it *IS* just as compliant with the ideal gas law as nitrogen or regular old compressed air. Please direct us to any charts that you might want to discuss, if they say otherwise.

Nitrogen expands and contracts with heat, too. That's why nitrogen charged air-spring shocks can actually change their ride height when they've been used heavily.

The reason that a nitrogen bottle will be filled to about 2500 PSI and that a CO2 bottle will fill to about 1000 PSI is that nitrogen is behaving more in accordance with the ideal gas law (PV=nRT) than CO2 and the pressure is going up as the fill amount increases.

CO2, on the other hand, follows those rules up to about 1000 PSI and then something really unique and very USEFUL happens. The CO2 starts condensing into a liquid. As the bottle continues to fill with gaseous CO2, the liquid continues to condense so that the gas phase pressure is constant. This eventually fills the entire bottle with room temperature liquid CO2 at about 1000 PSI. When you bleed off some of the gas CO2 from the top, the liquid below "boils off" instantly, maintaining the pressure. The pressure gauge will read a constant 1000 PSI while the gas continues to flow and flow. Eventually all the liquid will have turned into gas again, and the pressure will start to fall from 1000, just like an ideal gas.

Nitrogen tanks will start at 2500 PSI and the pressure will fall steadily while the gas is being used.

If you compare the AMOUNT of gas between the two types of tank, it's no contest. There is HUGELY MORE CO2 in the same sized bottle compared to nitrogen. That's why the CO2 tank is sold as a "ten pound" or "20 pound" bottle. The fill is literally capable of having that many POUNDS of gas in it.

You will get MANY more tire fills out of a CO2 tank.

That's why people are carrying them.

Nitrogen for tires comes from a completely different sales pitch that's being delivered to an entirely different audience. It comes out of high performance road car technology with low volume, high temperature, thin walled tires. From there, it filters out to the community and becomes a sales pitch.
__________________

[FJ FunJunkie]

bedu bandit previously said:

Anybody have any idea if a CO2 tank would be ok inside the vehicle in hot (read VERY hot!) conditions. Does the CO2 expand in heat?
Would it be risky inside the vehicle?

Apologies for the hi jack - hopefully its an extension of the original topic

Yes its
fine. People have been running these in vehicles in desert situations for years. I wouldnt throw one in a bonfire but even then it might survive depending on the tank rating, I had a 10kpsi Bottle roll through my shop today, i was tempted to snag it. lol

[Ramjet]

Very informative thread guys. Thank you. After this I know what to do.

[Corey]

Been using C02 in my tires since around '99 when I got my first Powertank.
Here is an ancient vid of me and the old rig changing my tires over using an impact wrench.

Most impacts like around 90 PSI.
Crank the tank to 100, then when you pull the trigger, the gauge will fall back to 90.
I think I only had it set to 90 in the vid, it will go much faster.

http://pnw4runners.com/tando/impact.mpg