So I was reading a thread on an off-road isuzu forum about on board air compressors and everyone was talking about using either a belt drive compressor or running a tank in the back of their truck. Off road folks like to have an air supply to air up their tires after riding or to run an air actuated differential locker. The perk to having an on board air supply is that you can also run air tools. One guy did a write up about using a 20lb CO2 tank (like used for fountain drink stations or kegerators) as an air supply and then plumbing it up like a home air compressor. He said he can run a cut off tool for around 11-12 minutes off a tank so you can imagine if you wanted to air up flat tires or carry it to impact some lugs etc...

I decided that it'd be fun to have as a portable air tank for air tools and I gathered all the parts. I picked up an old tank (or three) at an estate sale for about $15 each. I took the tanks to airgas and had them swapped out for $12.23 each. Next came the regulator which I got from HF with a coupon for $19.99. I also bought a 3/8" female to 1/4" male adapter for $.97 cents from HF. I had to drill out a pin-sized hole for more flow. Then I put on some quick connectors and a hose and...







Lots of power and I've played with it all weekend. Tore an engine down with air tools and impacted some wheels on Penelope. Aired up a few tires too. Its been really fun to think about all the possibilities! I know the limiting factor is the tanks have to be swapped at a welding supply place for a price, but it does allow for some freedom, especially when you have to go revive a VW out of a field.

I showed it to William last night and he was ready to build one. We worked out a deal on one of my extra tanks and I'm going to get him the coupon for the regulator. For the price, its pretty cool. Here is the coupon for the regulator (normally $39.99 and good through April 7th 2011):



Or link to print:
http://images.harborfreight.com/hftusa/itc/7751/images/86.jpg

I've read that Nitrogen expands 7 times when it comes out of a compression. CO2 expands 40 times because of the liquid to gas phase change. CO2 is also stored at a lower psi (about 800psi) compared to Nitrogen's multiple thousand psi.

I know that nitrogen is a lot more consistent temperature wise and thats why NASCAR uses them in their tires. They have also been offering to fill your tires with Nitrogen when you have them mounted because the "molecule is bigger than regular air and won't seep out of the rubber as quickly". I'll stick to my 78% nitrogen mix for free!

I'm not sure how much Nitrogen cost compared to CO2, but it was pretty cheap to get the CO2 filled!

cost is the same more run time on nitrogen been using it for years. every thing i own or drive has nitrogen filled tires. even have fieldings herbie raising with it. even run it in the mower tires. will fill 4 to 6 tires on my 3/4 ton work van. once i found 4 valve cores  some one releaved me of as a joke...

in my case nitrogen is cheap work supplied keep 2 tanks on truck hey its free why not..