Bad tank alloy

[Arkman]

Fair enough. Man what a bummer, I went from having 2 tanks to 0 in the matter of a few min :depressed:

I guess I'll go back to renting for a while. I've seen a bunch on craigslist but I've been scared off by the bad run in with these tanks.

 

[knotical]

If you'd like to learn more before your next purchase, these might help:
A short Review of 6351 Alloy Alu
Neck Cracks
http://www.phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/3al_advisory.pdf

 

[JamesBon92007]

Fair enough. Man what a bummer, I went from having 2 tanks to 0 in the matter of a few min :depressed:

I guess I'll go back to renting for a while. I've seen a bunch on craigslist but I've been scared off by the bad run in with these tanks.

Just so you'll know, you still may have two tanks--sorta. The DOT has not banned them, there has been no recall (as mis-stated earlier), and the DOT did not implement a 40 year expiration date, which they were considering. So, basically, if they pass the visual, the hydro, and the visual eddy they CAN still be used. That's up to you and the dive shop that fills them. I only called two dive shops but both will fill them. However, if you can really get $30 each selling them for scap then personally I'd take the money and put it toward either a new tank or fairly new used tank. The other catch is that if they have been full all this time they are likely to have "sustained load cracking" around the neck. I inspected my tanks myself before deciding whether or not to have them hydroed. One looked OK and passed all the tests. One looks like it has a "tool-stop mark" and the other looks like it has a neck crack. I'm not even gonna bother with the two that look bad. Keep in mind I'm not qualified to do visual inspections--I just read the instruction book and made my decision based upon what I saw to avoid throwing good money after bad.

As for Craig's List, I wouldn't pay more than about $20 for a used tank that needs to be hydroed and then it would have to look good, have air in it, and no major dings or any strange paint jobs etc. Maybe they can sell them for $75-$100 to the paintball crowd...

If you want to read more about it:

CDNN :: Analysis of Cracking and Rupture of 6351 SCBA and SCUBA Aluminum Cylinders

 

[Scared Silly]

The affected cylinders:
Notice No. 94-7; Safety Advisory; High Pressure Aluminum Seamless and Aluminum Composite Hoop-Wrapped Cylinders


What you need to do to requal them:
Hazardous Materials: Aluminum Cylinders Manufactured of Aluminum Alloy 6351-T6 Used in SCUBA, SCBA, and Oxygen Services--Revised Requalification and Use Criteria | Federal Register Environmental Documents | USEPA

Of course the practical side is to sell them for scrap.

Other than that everything else is BS.

 

[Superlyte27]

Our shop will not fill any pre-90 tank. Eddy current test or not. It's the owner's policy. Most shops in the Keys will not fill a pre-90 tank EDDY test or not.

 

[grf88]

Our shop will not fill any pre-90 tank. Eddy current test or not. It's the owner's policy. Most shops in the Keys will not fill a pre-90 tank EDDY test or not.

I can understand why they would not want to fill 6351 tanks but what do they believe to be the problem with non 6351 tanks made before 1990.

 

[DA Aquamaster]

Our shop will not fill any pre-90 tank. Eddy current test or not. It's the owner's policy. Most shops in the Keys will not fill a pre-90 tank EDDY test or not.

I am ok with an LDS deciding not to fill 6351 T-6 alloy tanks, but when they extend this to any "pre-1990" tank, it advertises ignorance. "Ignorance" and "your regular LDS" are concepts that are best kept separate so when I see such policies, I recommend the diver find a new LDS as it is hard to tell what other areas may be impacted by this this type of ignornace.

The 1990 date means almost nothing. For example, Catalina made aluminum tanks beginning in 1986 but has never in its entire history made a 6351 T6 alloy scuba tank. Consequently a "no fills for pre-1990 tanks" needlessly excludes all pre-1990 Catalina tanks. Similarly, Luxfer stopped using 6351 T6 alloy in AL 80s in December 1987 so a pre-1990 policy needlessly excludes all Luxfer AL 80s made in 1988 and 1989.

It is not a policy based on safety but rather on ignorance.

If a shop is going to have a fill policy based on tank alloy, it needs to reflect the flacts:

The following is a list of all scuba cylinders made of 6351 Alloy:
All aluminum tanks under Special Permit # 6498, 922, 7042, 8107, 8364, 8422
All Walter Kidde 3AL Cylinders
All Cliff Impact Cylinders
All Luxfer S80.8 Manufactured Prior May 1987
All Luxfer S72 and S100 Manufactured prior to August 1987
All Luxfer S80 Manufactured prior to January 1988
All Luxfer S50 and S92 Manufactured prior to April 1988
All Luxfer S30 and S63 Manufactured prior to May 1988
All Luxfer S40 Manufactured prior to June 1988

*Note: Catalina Cylinders were never made from 6351 T6.

Also note that 1990 does not show up anywhere in this list.

 

[Scared Silly]

I can understand why they would not want to fill 6351 tanks but what do they believe to be the problem with non 6351 tanks made before 1990.

Paranoia and cause it is too hard for them to train their tank monkeys to do anything but look at a date and for the most part by 1990 no one was using it. Regardless of the mfg. i.e Luxfer quit using it 1988 whereas Walter Kiddie quit in Jan 1990 and Cliff in July 1990. Of course Catalina never used 6351.

I could go along with this dating standard to a certain degree but the shops I have seen it in do the same for steel cylinders. Which there is no basis for.

 

[scubafanatic]

I am ok with an LDS deciding not to fill 6351 T-6 alloy tanks, but when they extend this to any "pre-1990" tank, it advertises ignorance. "Ignorance" and "your regular LDS" are concepts that are best kept separate so when I see such policies, I recommend the diver find a new LDS as it is hard to tell what other areas may be impacted by this this type of ignornace.

While I certainly agree with a 'boycott the idiots' theory, that luxury isn't always an option, in this case it's easier to acknowledge the existance of this particular 'urban legend' and just not even begin to fool with those tanks.

 

[DA Aquamaster]

While I certainly agree with a 'boycott the idiots' theory, that luxury isn't always an option, in this case it's easier to acknowledge the existance of this particular 'urban legend'

Avoiding the need to rely on an urban legend would require posting the above list and asking the tank monkey to scan the list for a few key details. it only requires knowing three key concepts:

1. Catalina = always ok
2. Walter Kidde (fairly common), "E" and "SP" special permit AL tanks made prior to 7-82 (still seen now and then with or without an added 3AL stamp) and Cliff Impact (almost never encountered) = always bad.
3. The magic "ok" date for any Luxfer tank is 6-88 or later.

If the tank monkey is smarter than most they can even remember that the magic "ok" date for Luxfer AL 80s (very common) is 1-88 or later.

For anything else that does not pass the screening criteria outlined in 1 thru 3, they just need to refer to the list and if it is not one of the other Luxfer tanks with an "ok" date, show the customer and decline to fill the tank.

Once again, I'd argue that if a shop has to rely on a "1990" date due to limitations in staff intelligence, you want a new LDS as they will screw up the far more difficult and complicated aspects of filling a tank.

and just not even begin to fool with those tanks.

If the tank is missed and is a 6351 T6 tank but has a valid qualification date stamped on it and has a "VE" stamp, the odds of it failing due to an SLC are far lower than a million to one, and in the vast majority of cases, "failure" in this case will mean a leak not a catastrophic failure, reducing the risk of a catastrophic failure to something lower than 1 in 10 million. So exactly what risk is being mitigated with this policy?