How to identify a Luxfer 6351 tank?

[mike_s]

The 6351 cylinders are not "crappy".... They just require an annual eddy current test in addition to the visual inspection.

A 6351 cylinder that passes annual inspection is just as "good" as a 6061 cylinder that passes inspection.



There's no reason not to fill a pre-1990 cylinder that has a valid eddy current , visual inspection sticker and hydro. Any fill operator who says differently is ignorant of the facts.

I've also seen one that passed hydro, the EDDY vis at the hydro facility, then an additional EDDY vis at the shop, then the neck started cracking when filling (first fill after hydro). but yet it passed all it's inspections.

I used to believe they were safe if properly inspected, but this proved it wrong and I saw it with my own eyes. they are not all safe.

why take the chance to find out if you're playing roulette with a tank? (or why put the fill station operation in the same situation.).

just not worth it.

 

[spectrum]

Ok... so how do you identify the supposedly crappy 6351 AL tanks from the others......say....6051 tanks?

It might make a difference when shops won't fill a perfectly fine 6051 tank because the dates aren't what they like to see.
I know there were planty of 6051's made before 1989 and they're supposed to be fine.
It's the 6351 alloy that was supposed to be bad.

I just want to be an educated consumer when shopping for air.

The simple answer is to not buy or count on using any aluminum cylinder over 20 years old. This gets you past the 6351 period.

Setting all of the technical reasons aside the reality is that due to ignorance, paranoia or as manipulation 20+ tear old aluminum cylinders are getting harder to fill.

Any cylinder including the 6351 cylinders can be technically inspected and if passed deemed fit for use. The trick is knowing that any given shop will fill it on demand.

Pete

 

[spectrum]

There's no reason not to fill a pre-1990 cylinder that has a valid eddy current , visual inspection sticker and hydro. Any fill operator who says differently is ignorant of the facts.

He may be ignorant but if his are the only whips in town you're not going to dive.

Unless you have your own compressor or use the cylinders exclusively with known 6351 friendly shops getting air can be iffy.

We'd all like to think we can educate the world but at the end of the day I just want to make sure I can dive!

Pete

 

[Leadking]

The 6351 cylinders are not "crappy".... They just require an annual eddy current test in addition to the visual inspection.
QUOTE]

DOT requires an eddy current test every five years(with hydro).

The DOT, when the examined catastrophically failed cylinders under an electron microscope, found that all these cylinders had cracks that were ignored for more than seven years. Seven vip's and a hydro!! That is why we now have an eddy current test every five years.

 

[JahJahwarrior]

The 6351 cylinders are not "crappy".... They just require an annual eddy current test in addition to the visual inspection.

A 6351 cylinder that passes annual inspection is just as "good" as a 6061 cylinder that passes inspection.



There's no reason not to fill a pre-1990 cylinder that has a valid eddy current , visual inspection sticker and hydro. Any fill operator who says differently is ignorant of the facts.

The fact is, 6351 alloy tanks are at higher risk of exploding. Fact is, my life isn't worth filling your tank. Fact is, there is no reason to fill a 6351 alloy tank. I don't want to fill them, so I will never fill one. Simple as that buddy.

Another interesting fact, I've seen two 6061 alloy tanks with cracks. A lot of shops really skimp on their vip's. Best shops will have something like the Visual Plus neck crack checking system, or a high quality mirror system that sits in the neck and allows them to inspect every single inch, much more accurately than a dental mirror and flashlight.

 

[Leadking]

You take a greater risk driving to the dive shop than of a 6351 tank exploding. Ignorance is treatable!

 

[mksmith713]

The 6351 cylinders are not "crappy".... They just require an annual eddy current test in addition to the visual inspection.

A 6351 cylinder that passes annual inspection is just as "good" as a 6061 cylinder that passes inspection.



There's no reason not to fill a pre-1990 cylinder that has a valid eddy current , visual inspection sticker and hydro. Any fill operator who says differently is ignorant of the facts.

Doc, I hate to tell you but MOST shops in Fla are ignorant of the facts.
When it comes time for me to buy new tanks (and I will replace my old Luxfers one at a time), my business is going to the shops who weren't ignorant and did fill my old tanks.

 

[mksmith713]

Has anyone ever brought up the debate about 6351 tanks being more susceptible to cracking if they're used in frigid water vs the same tank being used in warm water?

I've always been told that hot/cold/hot/cold back and forth up north caused more problems with cracking that anything else.

 

[mike_s]

Has anyone ever brought up the debate about 6351 tanks being more susceptible to cracking if they're used in frigid water vs the same tank being used in warm water?

I've always been told that hot/cold/hot/cold back and forth up north caused more problems with cracking that anything else.

tanks heat up every time you fill them. See the ideal gas laws.

so I don't buy temperature change as causing this.

 

[SparticleBrane]

You take a greater risk driving to the dive shop than of a 6351 tank exploding. Ignorance is treatable!

Same thing with overfilling LP steels to 3600psi...