Several people commented this past weekend on my CO2 setup, so I thought that I'd post a little information about it.
I have a 20lb CO2 tank.
It lasts me approx 6 months (I don't have an air compressor in my garage, so it's my source of air for tools, airing up, using the nail gun, etc). I know that that is a horrible way to tell you how long it lasts, but it's the truth. According to the chart on Powertank.com I should be able to air up 52 33x12.50 tires from 15 to 30psi, or 90 30x9.50 tires (what many Isuzus come with stock), or run an impact wrench for 11.6 minutes. They claim that is 400 lugnuts. I suspect that is an underestimation. They only claim that I'd get 11.6 minutes out of an air cut off wheel, but I spent 15+ minutes cutting some springs out of a jeep in the junkyard one day, and I didn't start with a full tank.
I have a Cornelius brand beverage regulator, with the 0-160psi output (in reality, I can't seem to make mine go to above about 145). It has a standard 1/4" NPT output, so a normal Lowes quick disconnect will thread right in. These show up on E-Bay for about $45, sometimes new for that price.
They look like this:
I have a 1/4" polyurethane hose from www.beavertools.com
- $14 and the part number is BA-1202. DO NOT USE THE CHEAP YELLOW PLASTIC HOSES. They don't flow very well at all, and are a safety hazard with CO2 (more on that later).
I have quick disconnect fittings from Home Depot. I started out with their Orange set (not Yellow, which is a different standard). They now sell a much better design, which doesn't require you to pull back on the outer sleeve to connect a tool. You can easily notice it in the store because the sleeve looks like it is stuck half way. These are wonderful, and Lowes doesn't carry them yet. They are compatible with the Orange (and I'm told Yellow) standard quick-connects, so you can upgrade or mix as you see fit.
I carry an impact wrench with 17mm and 19mm sockets (I actually found a single socket that flips that has 17mm on one end and 19mm on the other end). I also carry an air chuck, tractor trailer sized since it is much easier to hold. When I'm offroading, I carry my 3" cut off wheel. The air ratchet uses a ton of air (co2) and I have yet to find a place where it would fit that I couldn't use my hand held ratchet.
The tank sits on the floor, and is strapped both down and to the side of the truck.
I don't have any great pics of it, but you can see it in the back corner (mostly covered by the air mattress) here:
CO2 is stored in a liquid in the tank. 20lbs of liquid CO2. The gas at the top is obviously not liquid, and this is what you are using. As you draw gas out, the pressure in the bottle drops, and more liquid CO2 evaporates. The gas (and liquid) in the tank sits at 800psi. Compare this to a Nitrogen tank at about 2500psi, and 3000-4000 in a scuba tank. (For reference, a scuba tank contains about the same amount of energy as two hand grenades). Because CO2 only releases its energy as the liquid evaporates, the large amount of energy isn't stored in a "bomb" format. It would still be bad to have a tank cook off, and care should be taken around the tank (keep your axe swinging well clear of the tank, and secure the tank very well).
CO2 tanks also have ceramic disk pressure relief valves. These have a ceramic disk that breaks if the pressure in the tank gets too high. The co2 is then vented to outside the tank. One Planetisuzoo member had one of his tanks overfilled. On the way back to his house the ceramic disk burt. This caused a loud hissing noise, and a cloud formed in his truck. He rolled down the window, and put up with the noise until the tank was empty, then turned around and paid a visit to the place where he had it refilled.
Now, for the bad:
Once you are out of CO2, you are out. It costs $14 to fill a tank. CO2 gets cold when it decompresses. Real cold. If it is at all humid my regulator will become covered in ice (it still functions just fine). Your hose will become stiff. If you use a rubber hose, it can become like copper pipe it will get so cold. The cheap yellow plastic hoses can shatter once they are that cold. The poly hoses aren't expensive, and they will stay flexible when cold.
You can't use the tank for terribly long when the outside air temperature is below freezing. The liquid CO2 in the tank has to evaporate in order to be useful. At those temps, the evaporation doesn't happen very fast. We tried to use mine in a junkyard in January, and only got 5-10mins of use out of it until it just wasn't evaporating in the tank anymore.
The tank isn't light. My "20lb" tank weighs 40lbs full. If I get a steel "20lb" tank, it weighs 60lbs full. The "20lb" rating is how much co2 it will hold.