Ok - still new bar here and havent built any rockets or plastic models (another old hobby not getting back into atm) for years until a few months ago and am already tired of rattle cans. It doesnt help I currently live in an apt so dont have lots of room for overspray. In the past I had a paasche vl (unfortunatly still dont have it) and used a 20lb co2 tank and will be getting another airbrush shortly (not sure which - liked the vl a lot so probably just get that). I liked the tank as it is quiet and the start up cost is about the same as a good compressor and you dont need a moisture trap. Doing some research I see that nitrogen is also used. Anyone have any experience or pros/cons on one vs the other or is it 6 of one, half a dozen of the other?
Off the top of my head I can think of these pros/cons
co2 pro - "lower pressure" in tank since it is liquid boiling off vs high pressure tank
co2 con - co2 in a small area can be fatal
nitrogen pro - air is mostly nitrogen so less problems in a small area
nitrogen con - high pressure gas leak/rupture could be more energetic than the same in co2 tank - both not good either
Any other thoughts?
Nitrogen in a confined space can be fatal too-- ANY GAS that displaces too much oxygen can be fatal! Two technicians died back in the 80's during the space shuttle program, when they entered the engine compartment of the shuttle for maintenance after a launch scrub-- the engine compartment of the shuttle is flooded with nitrogen gas before liftoff to displace all the oxygen, to help minimize the risk of fire from any propellant leaks. They entered before the nitrogen had been flushed out with fresh air, collapsed unconscious and asphyxiated before anyone realized it. Not good to play around with.
I take it you have a good regulator... you'll be getting your gas at a welding supply?? TSC and other 'farm stores' now have 'welding gas' cylinders in a lot of the stores, and can set you up with a good exchange program with little or no demurrage. Oxy-acetylene Company (AOC) and other welding gas suppliers can too, but it just depends on what's handiest for you.
I'd tend to think that the liquid CO2 would be a lot more 'dense' than gaseous compressed nitrogen would be. Airbrushes don't use a LOT of volume, but seems to me that the N2 tank would deplete faster than the CO2 tank merely on a density standpoint. I wouldn't worry about the cylinder rupturing-- if you're getting it from a reputable dealer, the cylinders have to be DOT inspected, and recertified every so often. Besides, either way, if the cylinder DID rupture, you're gonna be halfway to the next county before you know what hit you anyway...
Might want to check your rental agreement on stuff like that, anyway-- some places might not allow high pressure cylinders in the residential units... even knocking a cylinder over and busting the head valve off will usually send them through a cinder block wall, and sheetrock seperating your apartment from the neighbors is like tissue paper in that case... neighbors might not like having a cylinder shoot through the kitchen wall while they're eating their wheaties some morning...
Just something to think about... OL JR