Exploding Tank in Utila

[Diving Dubai]

Experience is one thing. What are these qualifications that don’t have a piece of paper”?

Well since you ask,

As well as being trained in metallics and non metallics, I was a Non Destrucstive Test Engineer writhing areospace, specialising in Eddy Current, Ultrasonic, X ray amongst others. I held a Level III cert in 5 disciplines (with re certs every 3 years) . Most aircraft you fly on will have been inspected by a procedure I wrote. I taught not only NDT but vis inspections to the CAA and FAA engineers, and only a month ago was developing a techniques for inspecting carbon cylinders.

Yes I know my stuff, but unless I’d gained a cert from the PSA (either by sitting a course or submitting my quals) I wouldn’t have the authority to claim a cylinder is fit for service

 

[Diving Dubai]

No, You said that Eddy current testing on a non 6351 is not a test that can be performed.

FActually wrong. The only different in the alloys (eddy current wise) is conductivity.

The fact that the eddy current tester recommended is a POS and training - is less than basic (a proper Eddy current course is 2 weeks) doesn’t alter the laws of physics

 

[Wookie]

Well since you ask,

As well as being trained in metallics and non metallics, I was a Non Destrucstive Test Engineer writhing areospace, specialising in Eddy Current, Ultrasonic, X ray amongst others. I held a Level III cert in 5 disciplines (with re certs every 3 years) . Most aircraft you fly on will have been inspected by a procedure I wrote. I taught not only NDT but vis inspections to the CAA and FAA engineers, and only a month ago was developing a techniques for inspecting carbon cylinders.

Yes I know my stuff, but unless I’d gained a cert from the PSA (either by sitting a course or submitting my quals) I wouldn’t have the authority to claim a cylinder is fit for service

I'm not questioning your credentials. I'm sure you can UT with the best of them, and write procedures that could astound the smartest guys.

But we're not talking carbon cylinders here, we're talking about a specific test to find a specific problem in a cylinder made from a specific alloy. The cracking is in alloy 6351-T6 aluminum. If the test is performed on a different cylinder, the results are meaningless.

If I used your carbon cylinder inspection techniques to inspect a fiberglass cylinder, would you accept the results? More to the point, would the results mean anything?

C'mon, you work in QA. You know better than to use a test for one material on another.

 

[w3dge]

My understanding was that ECT can be used to detect flaws in cracks in all manner of metallic criteria. Just because its used to detect SLC in 6351, doesn't mean it can't be used to detect flaws in other materials.

Just my understanding though - can't say I know what I'm talking about

 

[tridacna]

Well since you ask,

As well as being trained in metallics and non metallics, I was a Non Destrucstive Test Engineer writhing areospace, specialising in Eddy Current, Ultrasonic, X ray amongst others. I held a Level III cert in 5 disciplines (with re certs every 3 years) . Most aircraft you fly on will have been inspected by a procedure I wrote. I taught not only NDT but vis inspections to the CAA and FAA engineers, and only a month ago was developing a techniques for inspecting carbon cylinders.

Yes I know my stuff, but unless I’d gained a cert from the PSA (either by sitting a course or submitting my quals) I wouldn’t have the authority to claim a cylinder is fit for service

Sounds like all your certs DO have a piece of paper!

 

[Neilwood]

Sounds like all your certs DO have a piece of paper!

But not the one that allows him to certify a tank as safe or fit for purpose.

 

[TrimixToo]

I'm not questioning your credentials. I'm sure you can UT with the best of them, and write procedures that could astound the smartest guys.

But we're not talking carbon cylinders here, we're talking about a specific test to find a specific problem in a cylinder made from a specific alloy. The cracking is in alloy 6351-T6 aluminum. If the test is performed on a different cylinder, the results are meaningless.

If I used your carbon cylinder inspection techniques to inspect a fiberglass cylinder, would you accept the results? More to the point, would the results mean anything?

C'mon, you work in QA. You know better than to use a test for one material on another.

I suspect his point might be that, for the most part, aluminum is aluminum, and any significant discontinuity in the metal can be detected by the same test because the pattern in the eddy current generated in the tank will be disrupted in the same way if there is a defect. That the tester was put together to check for SLC does not render it ineffective for testing tanks that are not susceptible to SLC. Similarly, a Magnaflux test will find defects (cracks and voids) in cast iron and steel with equal effectiveness.

Whether it's worth bothering to perform the test is a different question entirely. It's probably not, which could be PSI's point (I have not taken their course), but it's harmless to check. Charging for it when it's not worth bothering, as many shops do, is yet another issue but it has nothing to do with whether the test itself would detect defects in 6061 tanks if they existed in the area tested.

 

[tridacna]

But not the one that allows him to certify a tank as safe or fit for purpose.

Thank you Captain Obvious!

That “qualification” is not government (DOT) mandated. Print your own stickers and do your own visual inspections on your own tanks if you want. No shop will turn you down for fills. The Hydro Stamp is what certifies the tank “as safe”. A VIS sticker says that some guy with a cert that takes less than a day to complete has looked inside your tank and thinks it’s OK to use for the next year. I’ve seen some shops let interns do the inspection and sign off on those.

 

[Sam Miller III]

@tridacna from NJ who doesn't log dives

I certainly agree with you--110 %

When John Gaffney if NASDS created the VIP program in the 1960s it was a local voluntary program centered in SoCal and all the participants printed their own shop stickers.

During that time period and for 15 years I was an adjunct college instructor teaching Advanced SCUBA at a SoCal community college.

The second class after the initial pool check out was a mandatory class which I identified as "equipment inspection." Every student brought all their equipment to class including their tank(s) and presented it on a table in a lecture hall. My staff and I went from student to student examining the student's equipment and commenting on recommended improvements which were generally cosmetic in nature.

The second half of the class was devoted to the students tanks. Each student brought their tanks to class empty ready for internal inspection, If they had the 3/4 O ring tanks I had several US Divers tank wrenches to use to remove and replace the valves : If they had 1/2 pipe threads the local dive shop would remove and replace the valve for free

The local shop "The Aquatic Center" loaned me a set of "Plates" aka portions cut from SCUBA tanks from no corrosion to deeply pitted rusty not acceptable which I lectured about.

Using a small pen light we inspected and commented on every class members tanks. During those 15 years of instruction I never discover one tank that was unacceptable. After the tank was inspected the student was given a Aquatic Center VIP sticker which was immediately affixed to the tank.

A few year later Al Thompson who in 1958 established Professional SCUBA Repair in North Hollywood developed a "light pole" which was used in place of a pen light to illuminate the interiors of the tanks. which I purchased and used for inspections.

My son was honored with a post doctorate hyperbaric fellowship at Scripps. One aspect was attending the PSI course established and then taught by NAUI Instructor Bill High. According to Sam IVs notes and reflections the course covered the history of SCUBA tanks, laws involving HP cylinders and the proper SCUBA inspection techniques.

VIP has evolved from an idea by John Gaffney and NASDS, to a voluntary activity by shops, to now a mandatory inspection procedures class by Bill High and his PSI...and enforced as diving gospel. If you don't have the voluntary class credentials of a PSI class, with a certificate suitable for framing and displaying , they are identified as qualified PSI tank inspector but you are therefore not qualified to use the Mark 1 eye ball determine if there is rust or pitting in a SCUBA tank.

Certainly interesting how fast this self-governing sport which has been in the US for 70 years has evolved into so many specialized mandatory requirements

Sam Miller, III

 

[abnfrog]

tridacna again you are dead wrong about the stickers ( here in Ontario if you have a vip sticker from a NON_VERIFIABLE shop or agency MOST shops will tell you to go somewhere else (dive shop owners KNOW people do exactly what you are telling them to do ), if some one is SO cheap they cant or wont have the tank looked at and maybe save a life welllll...........im the only air fill in 100 miles ill fill a 6351 if its had a vaild eddy ...again if I trust the person /company who did it , REMEMBER ITS MY LIFE IM RISKING FOR 10 BUCKS !!! go to tobermory and spot the crap you just did and try to fill your tanks see what happens , those guys WONT fill anything over 10 years old .........