Drummer87- Welcome aboard, I think you'll enjoy this... Airtanks- The firemen you read previously have the professional experience to keep you safe, as close to the 100% as possible. Moving away from 100% is simply your choice.
That said, I chose to cross the line and use a 'slightly outdated tank, purchased and tested its' last year date of professional service (yea, I was cheap). Exterior was smooth and there was nothing to indicate abuse or any damage of any kind. But... it's typically not what you can see that allows high pressure vessels to come apart. I treat the tank very carefully, and immediately put a covering on it, and I keep it out of the sun.
Part of my decision in using the tank was based on speaking to a European manufacturer. He explained their tanks had a slightly longer use period in Europe and that US certification was based on DOT (Department of Transportation) evaluation for safe transport (thus some fairly rough handling).
Previous post are absolutely right - when you see a fully charged tank come apart, it gets real, REAL fast. I saw an aftermath photo of a blowup (15 years ago now), where a Toyota (Camry I think) had a tank come apart in the trunk while the guy was driving. He hit a fairly significant hickup in the roadway and the bounced tank (thrown in on other 'stuff' in trunk) ruptured. Trunk blown open, trunk bulged on most sides and the rear seat blown forward (not hard enough to hit the rear of the front seats and luckily he was the only person in the car). The guy was unhurt, pulled off the roadway under control. Screwed with his hearing, as you might guess... The funny part (once you know he was not seriously hurt) was what he said about the mist and dirt that instantly filled the passenger compartment- instantly he said he was in a dirty cloud bank inside his car, at highway speed. He went on to say he had no idea his backseat and speaker deck area could hold that much dust and dirt... His car was FUBAR'd.
When you decide to use an outdated tank, you simply make a risk judgement. Most of us decide to use outdated tanks due to the cost, thinking that outweighs the safety (ouch, reality sounds harsh)- If money were on no concern I would trot on over to Joe B's (ExpertHPA.com, an advertiser here) and buy the full Monty...
He knows his stuff inside out and can explain it at whatever level you're comfortable at (young retired Science guy- the propeller head physic's type). His stuff can be a little more pricey (not ridiculous), but his quality and service is outstanding!
You pay your money and make your choice brother... Best of Luck and Good Shooting! Hi-vel
