Average lifespan of aluminum cylinder

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akdeepdiver

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A solid wall cylinder may remain in service as long as it continues to pass the 5 year hydrostatic requalification with visual inspection, and Eddy Current test (for cylinders manufactured from 6351-T6 AL Alloy). I have tested, and passed, compressed gas cylinders at my hydro facilities that are over 100 years old. The oldest I tested and past was manufactured in 1912.
 

bakodiver391

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I have learned the hard way to never buy a cylinder without popping the valve off and taking a look inside first. No exceptions.
 

USdiver1

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I still use several of my 1978 manufactured Luxfor 6351-T6 AL Alloy cylinders, left over from my harbor diver days. Once they pass hydro and you VIP and eddy current them they are good to go. It may take some persuading to get a specific dive shop to fill them [especially in Floriduh]. What I do when travelling is check out which shops service the local commercial divers [pool cleaners, hull scrubbers] and gently insert myself into their customer base. Professional courtesy is almost always extended to a former harbor diver.

PS You trap more flies with honey than with sh*t.
 

Jack Hammer

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I see 40+ year old tanks in for annual eddy test and 5 year hydro all the time that pass. To me, it doesn't make sense to keep them. When I look at the cost of the annual visual eddy and hydro fees it almost adds up to the cost of a new tank. To each their own.
 

archman

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I had a 20-year old AL80 tank that always passed hydros and no dive shops in Texas had a problem with it. But the moment that I move into Florida, the first dive shop I try to get a fill for says that my tank is "too old and very dangerous" and refuses to fill it. They also refused to fill my old steel 72 tank even though its hydros were also valid. I got that tank from a retired UDT diver; it had swank.

So, a lot depends on the personal opinions of the dive shop that you go to.
 

rjack321

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I see 40+ year old tanks in for annual eddy test and 5 year hydro all the time that pass. To me, it doesn't make sense to keep them. When I look at the cost of the annual visual eddy and hydro fees it almost adds up to the cost of a new tank. To each their own.
I believe the current price for a requalification with VE here is $65+9.9% sales tax - which is just dumping money into a 20+yo cylinder. Certainly not worth buying used ones with those kind of requal costs.
 
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akchan

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I picked up 2 Catalinas for $100 then spent $25 each for Hydro. Will drop off for visual inspection for $22.

So I paid $125 vs $210+Tax. This does not include the visual. Guessing even if I buy new online and bring it to a shop, they will still charge the visual. So I saved $85+tax. I mean $85 is not huge but also not little?

I asked the hydro place if they have a punch card for buy 10 get 1 free. :) He said amusingly, nice try, we aren't Dunkin'

Also, just picked up well taken care of gear that included a Catalina AL80 manufactured 2007, all for $10! My deal of the month!

Sherwood Oasis 2 Primary and 2nd Stage & Sherwood Shadow + alternate 2nd stage
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Deep See Hood
Weight belt with 16lb of soft weights (4) 3lb & (2) 2lb
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Catalina AL80 Tank.
 

boulderjohn

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Quite a few years ago, a certain alloy used in some aluminum tanks was found to be susceptible to sustained load cracking. That alloy was discontinued immediately. Tanks with that alloy are still usable, but they call for more careful inspection.

The tanks in question in this thread were made well after that date and will not have that problem.

However....

Rather than check to see if an older tank was one of the ones that had that alloy, about 20 years after the alloy was discontinued, some shops developed a policy forbidding the filling of any aluminum tanks older than 20 years. That would make sure that they were not dealing with a tank with that alloy. They then kept that policy in place, keeping the 20 year rule even though it stopped making sense over time. Some shops still have that rule, even though it should now be extended to 35 years.

Here is an article about it.

 

rjack321

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Quite a few years ago, a certain alloy used in some aluminum tanks was found to be susceptible to sustained load cracking. That alloy was discontinued immediately.
Luxfer used 6351 aluminum from 1958 until 1987-88 depending on the cylinder size. So basically 30 years.
 

kammel78

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Luxfer used 6351 aluminum from 1958 until 1987-88 depending on the cylinder size. So basically 30 years.
And in that 30 years of millions of tanks, there haven't been enough incidents to warrant a recall of 6351 cylinders.
 
https://www.shearwater.com/products/peregrine/

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