Old steels denied fills due to store "policy"

[JackD342]

From what I have read there was a trade in program also it is more expensive to maintain them as the inspection requirements are different.


Luxfer updates inspection and replacement policy for scuba cylinders manufactured in the United States




https://www.luxfercylinders.com/support/faq-luxfer-6351-alloy-scuba-inspection

To my knowledge, the past trade-in program was not a blanket exchange program, it was basically an extended warranty for failed cylinders.
50 million? There are lot of numbers thrown out, rarely with clarification. First, scuba cylinders are just a fraction of total cylinder production. And is a number cited for worldwide production, or regional, or just one producer? The most definitive numbers I can find are from Luxfer, that says about 1.25% SLC failure rate of 1,073,000 Luxfer scuba cylinders from 6351 aluminum. Much lower for other industries.
How many aluminum cylinders have exhibited SLC?
I do not read that as a catastrophic failure rate. I also suspect that was sampled at a point in time, and incidence rate of SLC on a fixed population can only grow over time. You don’t see all those cylinders around, as so many have been removed from service. And however many were produced by Norris and Kaiser have been removed 100% due to expiration of DOT permit.

I inherited 19 Luxfer S74 (not a typo) 6351 alloy tanks about 9 years ago, and only have 7 left.
They were not all “true” eddy current fails, some were because I decided not to gamble on another 5 years when the expense of another hydro came due. If a cylinder has multiple single thread hits with my Visual Plus, and I can see a progression from previous inspections, I have a heart to heart talk (in this case with myself) about spending $$ on another hydro or sending them for recycling as scrap.

More than a few customer cylinders have also gone to scrap once we have an honest conversation including the cost of putting a 6351 back into service. And no, that is not a sales technique. They will almost always choose to rent rather than replace, and are happy to regain that space in the garage.

 

[Bob DBF]

We were a bunch of 21 year old sensitive navy boys who liked practical jokes, hard drinking, a few druggies, grabassing, and, oh yeah, running a pair of reactors.

You were with the old guys.

the very low catastrophic failure rates for non-AL 6351 tanks;

The catastrophic failure rate of 6351 tanks is low. Enough to put special procedures in place, but low.

Edit. FOund some testing data. 3AA cylinders tested to failure at 17,000 PSI for a 2250 cylinder. 750% of design.

I wonder how a rock would do.

Wait a minute, you are telling me that there are 5 times as many 6351 cylinders made then Ford Mustangs. Last year there was a big publicity about the 10-millionth mustang built.

They are still making Mustangs, 6351 stopped being used before 1990. Without looking at the tank stamps, and in some cases checking the list since some were stamped 3AL, there is virtually no way to tell the alloy. Sometimes the decal on the tank gives a clue.

Where I am, 6351 tanks show up on Craigslist, sometimes VE stamped, but mostly not advertised as 6351 because the seller legitimately doesn't know, or is trying to make a quick buck.



Bob

 

[JackD342]

According to the PSi document cited above, they have knowledge of 24 steel tanks in 2011

What isn't clear is how why and when etc

As I understand (and happy to be corrected) here is no legal requirement to report a tank failing on fill - unless there is a reportable injury or death.

I would bet your house (I'd bet mine but you don't' want to be on teh wrong side of my wife) on the fact there are tanks with non allowable defects, that pass hydro. Not because the hydro operator is lacking, but because its' more than possible. Hydro is just a rough test.

But that said - the fact that the failure rates are so low makes it a non event for 99.999% of divers thus the test procedures (If carried out correctly by a competent person) are as fit for purpose as reasonably possible.

Choosing who you trust to carry out your testing is like choosing a dive instructor - not all are equal.


Thus making a blanket statement that if a cylinder is in test it's 100% golden - not so much.

But finally. What really stirs my pot, is that the same people who will happily spend $1000+ dollars on the latest greatest dive computer and will change it every 5 years or so, are the same people who will argue against spending $300 on a new cylinder when its reached a life of 40-50 years. #doesn'tmakesense#

Even lower non-event for divers, if you only count one role at a time for a fill station operator. They are on the front line for (almost) any incident, not the cylinder user.

At the risk of misquoting, during PSI training Mark Gresham will frequently and emphatically repeat “don’t trust your hydro guy until you have learned to trust your hydro guy.” Or something like that...

 

[Wookie]

You were with the old guys.

Bob

The old guys were 26. Our regulators were 31.

Testing a scuba cylinder to failure isn’t about testing the cylinder, it’s about testing the containment fill station. When Bauer or Mako or whomever build containment fill stations, one out of some number must be tested for efficacy. Which involves blowing up a cylinder. The hoop wound SCBA cylinders (3600 PSI) are good to 15,000 psi.

 

[Wookie]

Even lower non-event for divers, if you only count one role at a time for a fill station operator. They are on the front line for (almost) any incident, not the cylinder user.

At the risk of misquoting, during PSI training Mark Gresham will frequently and emphatically repeat “don’t trust your hydro guy until you have learned to trust your hydro guy.” Or something like that...

Mark Gresham’s hydro guy happens to be mine.

 

[Diving Dubai]

And don’t even get me started on ducks.

Kick them with a size 12

The nice thing about SB you learn something most week, I enjoy your perspective and lessons you share especially about all things nautical

Point is, your background is dealing with light delicate flying things operated by elite operators who take care of their equipment. My background is in chunks of wood and rocks operated by Neanderthal’s.

Seriously - I can assure you I've beaten the cr@p out of an aircraft with a FBH, and only after 15 years have my knuckles healed from dragging on the ground. And then there's the marine corp

Fun aside, I get what your saying about aircraft being at the design limit and that true. The point I was trying to make is we think we know, we use maths and computer models to the nth degree, but they're only as good as the knowledge we have. Time and time again I've witnessed our knowledge to be lacking.

 

[txgoose]

a very small rock float

I am again disappointed in the entirety of SB for letting this gem go more or less unrecognized for its value.

its reached a life of 40-50 years. #doesn'tmakesense#

You have just added 10 years to your 30-40 year mark earlier in the thread. I think that it does make sense to you. You accused me of being ugly earlier. Again, I promise I am not trying to call you out. Just encouraging to embrace the evidence.

 

[Diving Dubai]

I really don't know how you do it and I live in Texas.

Not having to pay taxes is a great incentive

 

[Diving Dubai]

. Just encouraging to embrace the evidence.

It's not that I don't embrace evidence, but I've learnt to question accepted theories. I'm happy to be wrong, because being right often requires dire circumstances to have occured.

As to the number 20, 30 40, 50 or 60 it doesn't matter. At some point the risk outweighs the reward. Only the manufacturers know the true answer and they will give a lower number to C(Their)A

 

[Wookie]

I am again disappointed in the entirety of SB for letting this gem go more or less unrecognized for its value.

The entire board is used to and probably tired of me throwing little references to Holy Grail, Blues Brothers, Princess Bride, Rocky Horror, and Caddyshack. They wish I would go see Blazing Saddles, Lebowski, Thelma and Louise, Capt. Ron. Then I could change up my shtick.