What is the real life expectancy of an air cylinder

[deac99]

Hello,
I just heard that all air tanks on pistols are stamped with a date, and if it is over 10 years old and sent to a certified service place, they will destroy the tank by drilling a hole through it. I guess there is no practical way of testing the air tanks, so someone made a 10 year rule. Does anyone know how long tanks really last, say if they are well taken care of, kept at room temp, and refilled twice a week?

I am considering buying a used pistol, but if the 2 tanks are say 8 years old, I could be looking at an additional $500 to replace them in 2 years - does this make sense, or am I being overly cautious??

Thanks
Deac

[jipe]

I never heard that they will be automatically destroyed but well that they must be tested again just like scuba diving bottles.

[David M]

I expect that the ten years is a nominal time period set by some makers and this should allow for a substantial safety margin.
The real life would depend on fatigue cycles rather than time. But how do you accurately determine the cycle life. With the thin walls of our cylinders and the extreme pressure changes from full to empty, the expansion and contraction of each cycle will create fatigue leading eventually to a high pressure failure.
So rather than play with a time bomb, the safe way is to replace the old cylinders.
This is one area that the ISSF have not addressed as yet; I would not be surprised to eventually see the tanks checked at gun check.

[Nev C]

The instruction book that came with my FWB P34 says the cylinders have to be returned to the manufacturer every five years for testing.
I shudder to think what the cost would be to ship two cylinders from Australia to Germany, have FWB test them and then ship them back. it would probably be cheaper to buy a new air pistol.

[Misny]

I guess I'm really at a loss. I've been shooting air pistol for a number of years and have never heard of a problem with rupturing air gun cylinders. Is there an epidemic that I am not aware of?

[Steve Swartz]

Lawyers + Stupid Greedy People + Even Stupider Juries = Stupid Corporate CYA Policies.

(e.g. ridiculous warning lables on everything . . .)

Steve

[TORT REFORM NOW! LOSER PAYS/BRITISH RULES!]

[terrypchan]

The instruction book that came with my FWB P34 says the cylinders have to be returned to the manufacturer every five years for testing.
I shudder to think what the cost would be to ship two cylinders from Australia to Germany, have FWB test them and then ship them back. it would probably be cheaper to buy a new air pistol.

I was worried about this as well when I first bought my used P34, but a quick check with FWB via email and they said that pamphlet is outdated and the cylinders should be good for 10 years before an inspection should be performed. BTW, our host does air cylinder inspections for those of us in the USA, that might be worried about this problem.

Probably in the 10 year span of your air cylinder your AP will see service from your dealer for at least an o-ring/seals replacement/repair anyways. That would be a good time to have your dealer perform the air cylinder inspection if you or they feel the need.

[RobStubbs]

And of course all new guns come with new cylinders <not>. Mine were already 2 years old I think, when I bought the gun.

Rob.

[deac99]

Thanks for the feedback & comments - I was not aware that they could even be tested - I'll contact our host and see what they do for testing. It sounds like there is no standard process (Yet) for testing and certifying these.

[jackh]

My hammerli 480 K2 instruction book says "After 20 years, the pressure cylinder must be inspected by an authorized body (e.g. Hammerli). The year of manufacture is marked on the pressure cylinder."

[edster99]

And of course all new guns come with new cylinders <not>. Mine were already 2 years old I think, when I bought the gun.

Rob.

I bought a discounted one direct from Anschutz a few months ago and it was dated 04/2002...

Based on a few years exerience dealing with large numbers of scuba cylinders its certainly the case that if they dont suffer from internal corrosion they will last indefinitely. Generally test pressure is set at working pressure plus 50%. This is then tested for the total level of residual deformation after loading to this pressure. Bursting pressure of a 'sound' cylinder is very much higher, and often it is the fittings that fail not the cylinder itself (i.e. the valve in the top). For scuba cylinders a notional number of charging cycles before failure at test due to fatigue is expected at around 10,000. Now thats a lot of cycles !!! Despite news stories to the contrary, corroded cylinders rarely rupture catastrophically blowing shards of shrapnel around, but more often 'tear' open releasing the gas inside in a very exciting but less dangerous way.
Its possible to get steel cylinders rusty inside if they are charged with damp air, slowly leading to failure - especially if they are used for rich oxygen mixes - but the aluminium cylinders primarily found on APs are less susceptible to corrosion. Just dont put salty water in them!

I've got to agree with Steve

Lawyers + Stupid Greedy People + Even Stupider Juries = Stupid Corporate CYA Policies.

(e.g. ridiculous warning lables on everything . . .)


Dont worry about your cylinder failing... your body will have failed first!!

regds

Ed