Dive tank permanent expiration?

[captain]

1991 isn't the accepted cutoff date for a 6351-T6 alloy tank.

Thanks that could be suspect are:

ll DOT-3AL tanks manufactured under one of the following exemptions or special permits: 6498, 7042, 8107, 8364, 8422
All composite cylinders manufactured under one of the following exemptions: 7235, 8023, 8115
All Walter Kidde DOT-3AL scuba tanks.
All Cliff Impact DOT-3AL scuba tanks made before July 1990.
All Luxfer 80.8 cu. ft. scuba tanks (S80.8) made before May 1987.
All Luxfer 72 and 100 cu. ft. scuba tanks (S72, S100) made before August 1987.
All Luxfer 80 cu. ft. scuba tanks (S80) made before January 1988.
All Luxfer 50 and 92 cu. ft. scuba tanks (S50, S92) made before April 1988.
All Luxfer 30 and 63 cu. ft scuba tanks (S30, S63) made before May 1988.
All Luxfer 40 cu. ft. scuba tanks (S40) made before June 1988.
All other scuba tanks made in the US before February 1990 (except Catalina).
All scuba tanks not made in the US.

I'll make a correction. All of the so called bad tank issues deal with aluminum tanks not steel and most if not all arise from concerns, justified or not, from the scuba industry itself not from the DOT. The DOT has added specific procedures for testing aluminum tanks made in years past, mainly before 1990 but has not banned their use nor have they specified a definite service life if properly tested. As someone stated the only tank with a specified service life (15 years) are hoop rapped composite tank generally not found in scuba use. That being said the scuba shops can do and say anything they please but it may not be factual and in many cases it isn't factual.

All other ALUMINUM scuba tanks made in the US before February 1990 (except Catalina).

 

[Scared Silly]

This sticky post might be of help regarding Al6351 cylinders:

Is my cylinder made from the "bad" alloy aka AL6351?

 

[spectrum]

I have old tanks that were originally stamped 7/90. My dive instructor told me that in the U.S. they won't hydro a tank older than 1991, and that therefore my tanks are useless. Seems odd to me. If a tank can pass hydro why would it otherwise "expire"? Can anyone confirm this?

The only limited lifetime I know of pertains to newer composite cylinders. They do have a sunset.

6351 cylinders (not applicable to you) require specific testing and more and more shops are declining to work with them but they can still be used per regulations with the correct testing.

More and more shops are black balling ANY aluminum cylinder when 20 years old. This is a commercial decision, it's not technical or supported by regulations.

I do not know about Navy practices but they are irrelevent for civilian applications.

And they wonder why I don't bow when they say,"I'm an instructor".

Pete

 

[toddthecat]

I'd like to know something. Did he offer to take these "expired" tanks off your hands for you?

 

[mdeboard]

I'd like to know something. Did he offer to take these "expired" tanks off your hands for you?

He has them. My next class is tomorrow night. If he tells me they are "expired" I will, of course, take them back. I'll be curious to see whether or not they are the 6351 cylinders. I don't think that he's trying to pull a fast one on me. He seems extremely competent and claims to have been an instructor for many years. Anyway, I'm giving him the benefit of the doubt, and besides, this open-water course comes with complimentary reg, BCD and tank. I just had my own gear that I prefer to use if possible. I received a junior certification 20+ years ago, and have many dozens of dives under my belt, but when my best friend decided to get certified I thought it'd be a enjoyable and wise to take the open-water course with him as a good, thorough refresher.

Thanks to everyone for your responses!

 

[The Chairman]

Anyway, I'm giving him the benefit of the doubt,

Good for you! A few people get overly harsh on the internet and I have learned to just ignore them. Mistakes can have have been made. Opinions can and do differ. Assigning nefarious assent or stupidity based on either is just mean and should be avoided. Giving your fellow human the benefit of the doubt, demonstrates your own humanity.

 

[Diver Tim]

Just for info, I've had no problem at all getting my 6351 tank filled here (Hawaii). I've had it vis'd a couple of times; each time they've done they eddy current test for sustained load cracking.

 

[Peter69_56]

In OZ generally speaking anything before 1990 is suspect and many LDS will not fill them. You can have them hydrostatically tested but that doesn't mean anyone will fill them. Some shops here will fill them if they themselves Hydro and eddy test them but they generally appear to be an exception.

I get annoyed with people offloading these suspect cylinders on ebay to people (probably) just getting into scuba. There were some stories going around of people buying cylinders, getting them tested and then the test facility (or others) then not filling them (what a scam). The info below is from the Qld government website.

I was lucky and only had one cylinder before 1990 which I destroyed once I found it would not be filled. I was more worried about my or my wife's risk rather than a few hundred dollars. I now have a mix of aluminium and steel slowly going to steel other than my deco and pony cylinders. To destroy them its best to damage the threads where the valve screws in to prevent seal and valve fitting. One LDS used to drill a hole in them but when one he had recently condemned came back with a screw in the hole he had drilled (with tape over the screw to cover it), he changed his method. What a stupid customer to fit a mild steel screw into the hole, would act like a bullet and rust as well.


[h=2]Problem cylinders[/h]SCUBA cylinders manufactured from aluminium alloy 6351 are presently the main basis for concern. Workplace Health and Safety strongly advises that all SCUBA cylinders manufactured from this alloy, and other aluminium alloy cylinders 15 years or older, be non-destructively examined annually for cracks and flaws in the neck fold and thread areas by competent and suitably equipped persons.
This should be in association with annual internal visual and hydrostatic inspections by competent and suitably equipped persons covered by Australian Standard AS 2030.1:1999 The verification, filling, inspection, testing and maintenance of cylinders used for storage and transport of compressed gases. Part 1: Cylinders for compressed gases other than acetylene (non-Queensland Government link)(known as the SAA Gas Cylinder Code).
At risk SCUBA cylinders manufactured from aluminium alloy 6351 include:

• Luxfer aluminium alloy cylinders manufactured between 1972 and 1988 (check oldest hydrostatic test date stamped into cylinder).
• Luxfer aluminium alloy cylinder specification DOT SP6498.
• Luxfer aluminium alloy cylinder specification DOT E6498, E7042, E8107, E8364, E8422.
• CIG (Australia) aluminium alloy manufactured in or before 1990 (check oldest hydrostatic test date stamped into cylinder).

 

[Rich Keller]

Find a different shop, you are in FLA. I take my tanks directly to a hydro facility rather than to a dive shop that then takes them to the hydro facility. It's faster and cheaper.

Any shop can refuse to fill any tank, but if there is no good reason for their decision, go somewhere else.

In addition, the 6351 tanks can be used but need a eddy current test in addition to hydro and viz, at that point most shops still won't fill them so I dumped mine due to the hassle.



Bob
-----------------------------
I may be old, but I’m not dead yet.

Here is a list of DOT hydro facilities listed by state. PHMSA - Cylinders - Authorized DOT Cylinder Retesters: Domestic Not all of them work on scuba tanks so check them out first before you bring your tank in. The ones that do work on scuba tanks can also fill your tanks if your LDS will not.

 

[chrpai]

The ones that do work on scuba tanks can also fill your tanks if your LDS will not.

Can't say I've ever asked a hydro facility to fill my tank. I don't know that they do and if they did, I don't know that I'd want to breath it.

Personally I take my freshly hydro'd tanks to a friend that does VIPs. He then puts a couple hundred PSI in it for me and I take it in for a fill.