I originally saw this at http://www.schwedhelm.net/brew/biggasser.html. I have one of those little handheld CO2 chargers that uses the little disposable 12 gram cartridges. It works, but I don't like it for several reasons. You have to baby-sit it, or tell people how to use it, and then hope they don't mess with it too much. The cartridges aren't that cheap. You can't carbonate with it. If you hook it up to a gas disconnect that isn't attached to a keg and pull the trigger, it's likely to explode in your hand. Paintball CO2 tanks are much larger, they are refillable, and they can be connected to a regulator. There are several companies that make adapters that you can connect a paintball tank to a co2 regulator with CGA-320 threads. However, buying something like that is just no fun, and is not how i roll...

So here's what I did:

A while ago, I found a pair of nitrogen regulators on ebay that someone local was selling. I had been thinking about getting a stout tap, and a beergas system, so I got the two regulators for something like $20 and was able to pick them up instead of paying for shipping. I liked how they were more compact than the co2 regulator that I had.  It appears much larger in these picutres than it actually is.

So I had these two regulators sitting in my closet for a while, then finally decided what to do with the extra one. I took of the stem with the nitrogen fitting (cga-580). I bought: a 1/4"->1/8" adapter a 1/8"x2.5" nipple and a and a paintball "universal fill adapter". I screwed them all together and ended up with a nifty little paintball co2 regulator. (I also replaced the 0-100psi gauge, which was broken anyway, with a 0-30psi gauge, and added a ball valve and check valve to the output.)

I have a 9oz co2 tank that I use with it. I read that the 9oz size is small enough that I doesn't need to be hydrotested, but I don't know if that's true or not. I think I paid around $2.00 to get it filled at Dick's Sporting Goods. I don't know for certain how long it lasts because I have had some problems, including my jockey box springing a leak and the o-ring on the tank leaking. However, I can say that I dispensed at least one keg, and partially carbonated two other kegs on one 9oz tank, and it's still going strong. Also, you apparently have to replace the o-ring on the tank occasionally. I noticed that they sell these o-rings at places that sell paintball stuff by the 10-pack.