US Divers MK II 1974 Vintage Tanks

[coldwaterlloyd]

Can anyone confirm these are 50 cubic foot , DOT-SP6498-3000

Last Viz and Hydro was 2009

Are they the bad alloy ?

thanks in advance for info , Lloyd

 

[SandyRobinson]

I do not know how to post links to other threads but search here for the thread "How to identify a Luxfer 6351 tank". Then go to post 9 for the attachment. Appears that it may be because of the 6498 number in your description.

 

[SandyRobinson]

Oh crap - I need a lesson in attachments.

 

[Scared Silly]

Hey Lloyd, yup them be made from AL6351 See the sticky: Is my cylinder made from the "bad" alloy aka AL6351?

 

[Bob DBF]

My spidy senses make me want to see the neck stamps as soon as I see the chevrons.



Bob

 

[rsingler]

Lloyd,
You should be able to tell from the born date. If it is before 1972 or after June, 1988, you are okay. See the text copied from their website. Unfortunately, the Special Permit 6498 is almost certainly the bad 6351 alloy.
See also this website content from PSI:
PSI-PCI - A Brief Scuba Cylinder History

How can I tell if my Luxfer cylinder is made from 6351 alloy?

The easiest way is to check the original hydrostatic test date stamped on the cylinder crown. Luxfer manufactured 6351-alloy cylinders during the following periods:

• United States: 1972 through mid-1988
• England: 1958 through 1995

After the above dates, Luxfer began making cylinders from a proprietary 6061 alloy, which is not susceptible to SLC.

 

[coldwaterlloyd]

OK , thanks everybody , Is filling them up to 2500 psi with my eq hose from my hp tanks a danger ?

 

[rsingler]

At a min, it needs a VIS, and eddy current by a competent inspector. Lots of false positives with EC testing.
If it passes, then it could get hydro'ed by some stations.
If no one will hydro, then you have to decide your level of risk.
But here's a 6351 tank that my buddy asked me to VIS for him. OMG.

Classic (and unexpected) SLC (sustained load cracking).

 

[coldwaterlloyd]

They are retired . At 2 cents a pound I am cashing them in !