Aqua-Lung/ U.S. Divers Aluminum Cylinders from 70's

[DaleC]

OP is correct. Actually DOT has condemned that cylinder... Owning two, mine will be heading to the scrap yard when a favorable aluminum price hits....

Yep, show us the link where DOT condemns that cylinder. I'll show you the link where Bill High of PSI PCI discusses the subject. Pay close attention to the first sentence of paragraph four - it applies to you: PSI-PCI - Cracking and Ruptures of SCBA and SCUBA Aluminum Cylinders (Made from 6351 Alloy)

"Along with the wave of concern over cylinder failures has come a great deal of misinformation spread by inaccurate reports on the Internet, in newspapers and trade journals, as well as word-of-mouth rumors."


If you were stating your opinion as fact to customers the middle of paragraph nine in this report (by the same author) would apply:http://www.psicylinders.com/inspectors/library/18-a-short-review-of-6351-alloy-aluminum-cylinders

"Others state that the cylinder must be condemned outright. Such statements border on fraud and it is illegal to condemn a cylinder without proof that it is damaged beyond allowable limits."

 

[rhwestfall]

Ironically, it was information over thje last year gained here on SB that put me in the frame of mind that tanks with the following stamps were no longer servicable:

DOT SP 6498 Z 9439 & Z 4151. If I recall correctly, the "Z 9439 & Z 4151" were the death nails...

If in fact that is not true, this very place gave me that information ort links to what appeared valid to make that assumption.

 

[duckbill]

http://www.scubaboard.com/forums/tanks-valves-bands/272578-u-s-divers-tank-dot-sp6493-question.html

 

[Scared Silly]

Read this link and the links to the official CFRs:

http://www.scubaboard.com/forums/ta...66-my-cylinder-made-bad-alloy-aka-al6351.html

 

[DA Aquamaster]

Oh good lord....

In most cases the belief that 6351-T6 tanks "can't be used for diving" stems from one of three mis-interpreted pieces of information.

1) There were several special permits used to make 6351-T6 Alloy aluminum tanks before DOT adopted the common 3AL standard. Most of those special permit tanks were brought in under the 3AL standard and requalification facilities were instructed to stamp them "3AL" when they came in for hydro. Almost 30 years after the fact there are still some out there without the 3Al stamp, but they are still legal to hydro and use for compressed diving gases. It is a fact that there are a couple of permits where the manufacturers did not bring them forward to be certed under the 3AL standard and those tanks cannot be legally filled or requalified, but that does not mean that the other former special permitted 6351-T6 tanks can't be filled.

2) 6351-T6 alloy tanks require a visual eddy test as part of the requalification process, and most shops still insist on an annual visual eddy/visual plus inspection. Since the eddy current/visual plus protocols were implemented over 10 years ago, there has been no catastrophic failure of a 6351-T67 alloy tank due to sustained load cracking. A large number of them have failed in the requalification or VIP processes, but that is the point - any crack in a properly inspected tank will be detected before it will propogate to the point of a catatrophic failure risk. Still, some shops just won't fill them despite proper inspection status.

3) The DOT only prohibits the use of 6351-T6 tanks from use in trasporting hazardous chemical and gasses - not compressed breathing gases. But some people read the reg far enough to see 6351-T6 tanks are prohibited and then fail to either finish the passage or realize what section of the regs they are currently reading.

 

[DaleC]

If in fact that is not true, this very place gave me that information ort links to what appeared valid to make that assumption.

Dis is da interwebs...

Anyone can have an opinion or state total BS as fact and it can be very hard to decipher what is real and what isn't. I always ask myself two questions when reading anything on the net: Does this person seem to be stating opinion or fact and what's their motivation for sharing. Some people may be motivated by fear, profit, ego, ignorance or laziness. Some people look at risk objectively and some cannot tolerate even the suggestion of risk. Some cobble facts from varying sources and patch them together to make an assumption based on faulty logic. Some just do what the other guys do and thus create a form of erroneous conventional wisdom.
I once had a debate with a guy here who stated he tested 6351 cylinders and that 80% of them failed. I did the math to show him how crazy ithat sounded (year one: 25,000,000/5-80%=4,000,000... year two: 21,000,000/5-80%=3,360,000... ) but it didn't matter. That was his truth.

I like to refer instead to profesionals like PSI PCI. They are the guys who train the people who test the cylinders and spend every working day studying the issues surrounding them. They have no profit motive either way that I can see and would be the first to speak out if filling properly inspected 6351 tanks were a safety issue as it would directly affect both their health and professional credibility.

 

[John C. Ratliff]

A friend gave me two Aqua-Lung/U.S Divers aluminum cylinders from the early 70's. They are brand new, never been used and still in the original boxes. I did some research I know they are Luxfer cylinders made with Aluminum 6351 and are pretty much useless for diving. However, I am wondering if there is any collector value to these cylinders. I opened up one of the boxes to get pictures, but the other is still in the original unopened box.Is there any value to these or are they only worth their weight in scrap aluminum? I have seen similar J-valves going on Ebay going for $40-60 so maybe the value is in the valves?


View attachment 102044View attachment 102045
Thanks in advance for any info!

I had a set of these that I used as doubles for a few years. I simply mounted a PVC tube between the tanks, and put about 12 pound of lead in them. I had Marvel pack weights which were two-pounders and which fit into the PVC tube, with a quick release. I still have it--the Marvel Pack that is. Another thought is to use the cylinders with a Dacor Nautilus, which as weights. The cylinders are a bit longer than normal, but that's not much of a problem.

SeaRat

 

[Seahuntjerry]

Add 9lbs to your belt these are called telephone poles.
When they came out right in the USDivers catalog No vip neccessary.
I like my stell 38's,42's tripple 44's etc.
Jerry