Tank age and Max # of Hydros

[tomfcrist]

So, the questions that need to be answered are were any of those cylinders within hydro and passed the last annual visual, and if so, were they subjected to abuse that would have caused even a modern tank to fail??????? Pictures prove nothing without the facts.

I had a close call with a 6351 tank a few years back...I had just done the hydro and the vis(both passed with flying colors)and the tank started to fail while i was filling it. Kicked everyone out of the shop, turned off the bank, and opened the bleed before i ran out.....everything turned out ok that time.

 

[redacted]

I had a close call with a 6351 tank a few years back...I had just done the hydro and the vis(both passed with flying colors)and the tank started to fail while i was filling it. Kicked everyone out of the shop, turned off the bank, and opened the bleed before i ran out.....everything turned out ok that time.

How about explaining "started to fail" and exactly what you found in your examination after the tank was empty.

 

[PhilEllis]

6351 tanks are more prone to sustained load cracking in the neck, but they can still be filled by dive operators. They were made prior to 1990, and require an eddy current NDI inspection yearly.....I've only seen a few of these fail, and have never heard of a failure in the newer 6061 alloy. Most dive shops will still fill these, its only the uninformed that have a problem with it.

I assume when you say that "most shops will still fill these, its only the uninformed that have a problem with it" that you are talking about 6351T6. Is that correct?

I had a close call with a 6351 tank a few years back...I had just done the hydro and the vis(both passed with flying colors)and the tank started to fail while i was filling it. Kicked everyone out of the shop, turned off the bank, and opened the bleed before i ran out.....everything turned out ok that time.

So, you PERSONALLY have an experience with a 6351T6 cylinder where you "had just done the hodro and the vis(both passed with flying colors) and the tank started to fail while i was filling it"? Even after that, do you continue to believe that it is "only the uninformed" that refuse to fill these cylinders?

I would love to hear your thoughts on this experience.

Phil Ellis
Discount Scuba Gear at DiveSports.com - Buy Scuba Diving Equipment & Snorkeling Equipment

 

[tomfcrist]

yes, I am referring to 6351t6 tanks....by started to fail i mean i started hearing a hissing from under the valve, and it wasnt n O-ring. When i inspected the tank after it was empty, the crack extended from the top of the threads all the way down into the shoulder of the tank.

Yes, i still fill these tanks regularly, and this is why. It is my contention that the EXPLOSIVE FAILURES of these tanks are due to set it and forget it filling practices that i have seen some shops use. I have seen setups that fill at a given rate, and automaticly shut off at a desired pressure. If I had not been attentively filling that tank, things could have happened much differently, however this wasnt the case. Statisticly speaking, the chances of actually seeing this happen again in my presence is astronomical. If you dont believe that, ask around and see how many people have actually seen a tank crack, and then ask them how many tanks they fill per year.

If DOT still allows the use of these tanks, who am I to push buisiness away due to fear of an occurance that will probably never happen.
Just my opinion

 

[PhilEllis]

yes, I am referring to 6351t6 tanks....by started to fail i mean i started hearing a hissing from under the valve, and it wasnt n O-ring. When i inspected the tank after it was empty, the crack extended from the top of the threads all the way down into the shoulder of the tank.

But, it was properly inspected before the fill if I remember from your previous post.
That must mean that this crack was far from the takes-years-to-develop story that we are told.

Yes, i still fill these tanks regularly, and this is why. It is my contention that the EXPLOSIVE FAILURES of these tanks are due to set it and forget it filling practices that i have seen some shops use. I have seen setups that fill at a given rate, and automaticly shut off at a desired pressure. If I had not been attentively filling that tank, things could have happened much differently, however this wasnt the case. Statisticly speaking, the chances of actually seeing this happen again in my presence is astronomical. If you dont believe that, ask around and see how many people have actually seen a tank crack, and then ask them how many tanks they fill per year.

I have also seen exactly what you describe....a properly qualified tank, with the VE inspection, that also passed a vigorous visual inspection after hydro. The crack opened to the point of leaking on the first fill after hydro and inspection. The crack was about 3 inches long, and began to leak when the cylinder was filled to approximately 2400 PSI.

If DOT still allows the use of these tanks, who am I to push buisiness away due to fear of an occurance that will probably never happen.
Just my opinion

This is what makes this country great. Each of us, as business men, get to make that choice.

Phil Ellis
Discount Scuba Gear at DiveSports.com - Buy Scuba Diving Equipment & Snorkeling Equipment

 

[mksmith713]

But has anyone ever seen a catastrophic failure on a steel tank that's current in hydro and vis?

 

[duckbill]

But, it was properly inspected before the fill if I remember from your previous post.
That must mean that this crack was far from the takes-years-to-develop story that we are told.

Yes, I find this inconsistent as well. This does NOT sound like SLC at all.

 

[drdaddy]

yes, I am referring to 6351t6 tanks....by started to fail i mean i started hearing a hissing from under the valve, and it wasnt n O-ring. When i inspected the tank after it was empty, the crack extended from the top of the threads all the way down into the shoulder of the tank.

Yes, i still fill these tanks regularly, and this is why. It is my contention that the EXPLOSIVE FAILURES of these tanks are due to set it and forget it filling practices that i have seen some shops use. I have seen setups that fill at a given rate, and automaticly shut off at a desired pressure. If I had not been attentively filling that tank, things could have happened much differently, however this wasnt the case. Statisticly speaking, the chances of actually seeing this happen again in my presence is astronomical. If you dont believe that, ask around and see how many people have actually seen a tank crack, and then ask them how many tanks they fill per year.

If DOT still allows the use of these tanks, who am I to push buisiness away due to fear of an occurance that will probably never happen.
Just my opinion

Yea, about 10 years ago I had one of these aluminum tanks. It had passed hydro and vis, but then the tech decided to really take a look - micro crack (not uncommon) had developed in the neck - probably during hydro. It became a wind-chime.

I love my steel HP 3442s. My shop says there's no problem w/hydro-ing the PSTs (3 of the 80s and 1 x 100). I am very careful not to let another shop do anything with them because they have special hydro instructions. But I do feel better about my Worthingtons (3 x 100s). Oh, and I do have 3 of the later aluminum 80s, as well as assorted ponies.

 

[PhilEllis]

Yes, I find this inconsistent as well. This does NOT sound like SLC at all.

I have no evidence. However, despite Luxfer's claim that it is impossible, several of the fatal or near-fatal accidents have had the same fact descriptions of exploding in a state other than burst-before-leak. I would find it difficult to believe that various sets of people can report a near identical set of facts about various different accidents.

The manufacturer said the cylinder that I witnessed personally had to have been exposed to "user abuse and unsafe filling practices". I don't know and I can't say for sure, because I know nothing about the full life of the cylinder. I do find it quite surprising that the people who use the "user abuse and unsafe filling practices" line can never describe exactly what those practices are. But, this one leaked from a rather large crack in the neck and shoulder that was not discovered that same day by the hydro, the visual inspection performed by the hydro facility, the eddy current test, and my inspection back at the shop. It was almost as if this crack came out of nowhere.

Oh well.

Phil Ellis
Discount Scuba Gear at DiveSports.com - Buy Scuba Diving Equipment & Snorkeling Equipment

 

[Jim Lapenta]

Good talking to you just now Phil! In any case here in our area, right or wrong there are three hydro places that will not even look at ANY al tank older than 15 years right now. Yet one just had no problems with my 72's from 53 and 55. What it comes down to is that due to the issues with the "bad alloy" some places are doing what they see as best for themselves. IS it? Who can say. It only takes one accident to ruin a business or a life and for some that risk is just not acceptable. I can buy new AL 80's for 150 bucks with pro valves. But what I have except for one HP80 and one Al 80 are all LP steel tanks. As evidenced by my older 72's they will most likely outlive me and there is a chance my grandkids could be using em! It all came down to cost vs lifespan for me. When I bought my tanks I was working alot of OT and had the money. Now I'd be lucky to afford what I have, I might have had to go with AL. I just had my 40, and 19 done. The 30 had a fresh hydro when I got it last year. The AL80 is spare bottle now for checkouts and in the future a stage God willing. I keep my eyes open though for LP steels all the time.