Help deciphering tank stamp

[Scared Silly]

Thanks for the info. They are AL80s, a bit off on dates but here they are if this helps in decisions of safety.

The cylinders, though made from AL6351 they have been the correctly re-qualified. As said above, getting such cylinders filled is another story.

 

[scubadiver888]

I'm pretty sure everything made before 1980 would be 6351 alloy. If they are 6351 alloy then they suffer from SLC. Some shops will still fill them but they should have a eddy current test or what is sometimes called a VisualPlus test. I'm not sure if a hydrostatic test would be sufficient. Do they have a visual inspection sticker? Does it say they have an eddy current test?

 

[Trance]

Yes they have a visual sticker which is performed after successful hydro.

 

[Scared Silly]

I'm pretty sure everything made before 1980 would be 6351 alloy. If they are 6351 alloy then they suffer from SLC. Some shops will still fill them but they should have a eddy current test or what is sometimes called a VisualPlus test. I'm not sure if a hydrostatic test would be sufficient. Do they have a visual inspection sticker? Does it say they have an eddy current test?

Much of what is written above is not correct. Read this thread, as a dive master you should know this information.

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

The date most often used though still incorrect is 1990.

A cylinder made from AL6351 may suffer from SLC.

A hydrostatic test is only one component of what is really a re-qualification test. There is also visual component.

A cylinder made from AL 6351 in the USA will have a Visual Eddy at the time of re-qual. No other is required, though the scuba industry standard is to also perform one when an annual inspection is done.

 

[Trance]

Thank you Silly for the link! Very informative!

 

[keyshunter]

should also be noted that Walter Kidde never changed alloys in their aluminum tanks, so unlike Luxfer where the Pre-88 rule applies to the safe alloys, all Walter Kidde aluminum tanks have the 6351 alloy.

Yes and AFAIK Catalina never used anything but 6061.

 

[GrainDane]

I have a friend who lent me a couple of his tanks which are Professional AquaLung/US Divers from 78/79. Last hydro in 84. Local shop took them, passed hydro, and refills them. Wonder if I should cease using them or not. Local shop even replaced a valve for me...

Trance, if these tanks do not have "VE" stamped after the new hydrotest dates, they are not legal for use. Your tanks MUST have an eddy current test done. If the shop says they did the VE, ask for a copy of the VIP as this will have the serial number and model number of an eddy current machine if used. If there is no VE or they cannot provide proof, get your money back for the hydrotest because you (or your buddy) will be paying for another one wit the eddy current test done. Eddy current is not seperate from hydrostatic testing. It is part of the test on these older aluminum tanks and makes your tanks illegal without one.