Have you ever dove with a bomb ? (6351 Alloy Tanks)

[Sludge]

VIP+ was invented because of those tanks / alloy. It is a requirement to keep them in service. Other Aluminum tanks VIP+ is a good idea but not required (if I understand correctly).

Gary knows so much more about diving than me that I feel like a real goober correcting him, but this is one of my areas of expertise, so...

First, the nomenclature is incorrect. VIP+ is a visual inspection coupled with a valve rebuild, first trademarked by NASDS and assumed by SSI in the merger (although SSI allowed the trademark to expire). The eddy current test sold by Advanced Inspection Technologies is called "VisualPlus." Sounds similar, but not the same.

Second, in the instruction manual for the VisualPlus, it specifically states that it is not to be done on 6061 aluminum (the current alloy Luxfer and Catalina use), as it may cause false positives.

We have a dandy little device for looking for cracks in necks that is a lighted magnifier/mirror. I use it on all visuals, even steel cylinders. Only the 6351 and 6495 cylinders get inspected by the VisualPlus. If you ask my opinion, they should be sold for scrap, but the bossman tells customers we'll do them, and it's ten bucks for me. Here's the clincher, though: I'll fill them right after I inspect one, but not again unless I inspect it again. We have enough divemasters hanging around the shop that do fills. (I know, that's irresponsible, but my hands are tied. I personally advise the customer to trash it, but people are idiots.)

[bletso]

I am in the hydro business and in the SCUBA business. I have visited 100's of shops over the years and my observations are damning to the SCUBA industry as a whole.

1. I have seen shops do the 2 min visual. open the cyl, poke a light in and charge you at the time 12-15$. Well reputed shops didn't even have the proper equipment to do a proper thread inspection. If I am asked to fill fill an older cylinder, I refuse if I didn't do the inspection. I have little faith in the VIP inspection program of scuba shops in general. I don't care if their inspectors are trained by PSI, TDI, PADI, NAUI, or not. (I authored to whole TDI VIP program). The test is only as good as the individual performing it.

If shops had been attentive and doing their jobs, an in-effective eddy current test would never have had to be done. I would like to point out that the vast number of cracks I have found over the years originated in the shoulder area, an area most shops aren't equipped to inspect properly. Eddy current can not inspect this area. It still requires a diligent visual inspection. All the leakers I have found in hydro, leaked in the shoulder. BTW, VERY IMPORTANT, a cylinder can pass hydro and leak from a crack. (Hydro pressure is only maintained for 30 seconds and water is very dense as compared to a gas.)

2. Far more SCBA's have failed than SCUBA. The SCUBA industry went proactive and then banned (up to individual shops) older cylinders.

3. They (shops) require an eddy current inspection on all cylinders, even though 6061 material has NEVER been implicated in the 6351 stress cracking problem. (EXCUSE MEEE, Sustained load cracking) The DOT does not require an EC test on any 6061 material and this includes older Catalina cylinders. (Catalina never manufactured cyls from 6351 material.)

Luxfer, realizing they had a problem, aided in the design of the visual + machine to simply CYA and PR. They offered sweet heart deals to dive shops the try and find the problem cylinders. When this was brought to light, they divested themselves of their investment in that company)

In the mean time congress got into the act and developed regulations to address the problem which had been really blown out of proportion. (typical) If it wasn't for me and my company and only a dozen gas industry respondents the regs would have been far more burdensome even to the point of requiring specific eddy current machines to be used. (we also manufacture a competing EC unit)

Luxfer maintains that a cylinder hydro tested and eddy current inspected once every five years is sufficient. They say a crack takes 5 -7 years to progress to a state of probable failure. They also say any crack less than 2 threads in length is an acceptable condition.
Having worked in the metals industry for over thirty years, in a stress area such as a cylinder under pressure, or aircraft, I disagree and condemn a cylinder if any crack is found.

There was a proposal for a 40 yr life on these cylinders, Air Liquide and the CGA (Compressed Gas Association), opposed this and the DOT dropped this requirement.

I guess I agree with shops refusing to fill older cylinders, but I don't agree with their rational. I heard a shop/destination owner tell a customer last week, "We don't fill older cylinders because they are exploding on us". Now that was an out and out fabrication. He does profit by renting them replacement cylinders.

I also strongly disagree with the now accepted industry standard to require EC on all aluminum cylinders, regardless of age. It is just a way to justify higher prices for VIP's or rent more cylinders.

Flame on all,

Dale

[Sludge]

in the instruction manual for the VisualPlus, it specifically states that it is not to be done on 6061 aluminum (the current alloy Luxfer and Catalina use), as it may cause false positives.

This was the VisualPlus machine we got in 2001. I went up to the other shop I work in, which has a VisualPlus 3 machine from 2005, and the manual says it can be used on 6061.

Although I've never heard anyone say 6061 cylinders need to be ultrasonically tested.