Air tube expiration date

i wonder what happens if the company goes out of business or no longer makes that kind of air tube in 10 years time?

In reality, all aluminum air tubes do have a finite life...just like scuba tanks do. The issue is aluminum does not have infinite fatigue life at any load level. This is why planes are inspected to replace parts that show signs of fatigue (wing panels for example.) In reality, PCP's don't get close to the number of cycles required for failure. However, the potential is there. A PCP that is used at a range, for example, which would get lots of cycles, would be the greatest risk. The fact that we don't hear of these things failing at ranges suggests they are generally designed for very high cycle life. This is one reason designers require ultimate strength to be much higher than the working pressure.

Hi Joekrooz,

Some of my PCPs w/tube reservoirs mention an annual inspection of the tube in their manuals. Essentially take a peak inside and look for corrosion. I think that is a good idea as a wet fill combined with materials that are not designed to be wet could lead to real problems.

That being said, if you think you will be shooting the airgun beyond 10 years, I'd buy a spare tube. The clock really doesn't start until the tube is used unless there is some inherent flaw in the material.

As far as aluminum SCUBA tanks are concerned, I did not realize they had a life. VIP every year and hydro every 5 years. AL6351 aluminum tanks on the other hand are known to be problem children.

IMHO,

YMMV,

Nugria

ALL...pressure vessels have have a finite life and much be checked (a yearly or bi-yearly schedule) before "legal" refills, steel, aluminum, carbon fiber, all of them. Just ask OSHA. I'd assume that there is some clause for small tanks like on air guns.

As noted in an earlier thread, if you nick (especially a sharp edged nick), dent, or other indication, it might benefit you to change tanks. Explosions at 3000+ psi isn't pretty. 

As for aircraft, there was a time when checking aircraft fuselage was a much simpler task. Back when cigarette smoking was allowed on flights, the inspectors just looked for smoke stains on the outside of the fuselage. That indicated a leak between panels or a broken/cracked panel.



Mike

I thought i have read somewhere if the tank was under 2 inches in diameter inspection wasn't required. Length of usable life, I dont know.

Airtube do not have the 15 life such as the cf bottles. I guess they put that on their airtube so they can't be sue if anything happens after that. But all airgun with airtube do not have a life spam. If you take care of it and fill with clean dry air. It should last a lifetime.

It's a world market and some countries (and organizations) require such markings and you can not compete using an out of date ( or not marked) tube. 

No "need" to test , but, everyone used to use DRY air.



John

Alu does fatigue, carbon fiber does not. There was a fatigue test done on a set of carbon fiber MTB handle bars. The fatigue testing machine failed at over 1 million cycles but the bars didn't. Alu MTB handle bar won't come near that many cycles before breaking. 

Carbon fiber may not fatigue but NO air tank that I know of is pure CF. CF air tanks are aluminum core, carbon fiber AND glass fiber wrapped.