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80'S AL Tank Inspections - Eddy Current?

Discussion in 'Tanks, Valves and Bands' started by MMac, Feb 4, 2007.

  1. MMac

    MMac Guest

    # of Dives: 200 - 499
    Location: Fresno,CA
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    I reciently had three AL tanks fail the eddy current for VIP at a dive shop. They then stamped them "failed". I then had them tested at two other dive facilities and they passed fine.

    The first shop is certified by PSI out of Seattle,WA.

    Anyone have any ideas as to which goverment ennity, if any, has the say on who would be correct?

    Anyone with any ideas with a course of action.

    Thanks
     
  2. DiveSite

    DiveSite Nassau Grouper

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    What are the original hydro dates on the tanks that failed?
     
  3. Ann Marie

    Ann Marie be happy ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: California
    3,491
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    Did the shop say why the cylinders failed? How old are the cylinders? To fail the visual inspection there would have had to been significant corrision, physical damage to the cylinder, or a neck crack (or other thread damage). The eddy current looks for neck problems, including valleys or cracks...was the shop able to show the crack to you? If the thread damage can not be seen visually, the shop probably should have contacted the manufactor before condeming them.

    I can't imagine the odds of having 3 cylinders fail unless something odd has happened to all the cylinders in the past.

    If it were me, I would take all documentation back to the original tester and ask them why the cylinders failed when 2 other testers passed them.

    Unfortunately, the cylinders are now useless. You won't be able to get an air fill with the dates stamped out. Again if it were me, I would expect 3 new cylinders from the original inspector unless they can show/explain to you why they failed especially when 2 other shops passed them. Did the other shops perform eddy current testing?

    If the cylinders are newer (made of a different alloy, 6061), DOT doesn't even mandate an eddy current testing.
     
  4. JahJahwarrior

    JahJahwarrior Solo Diver Staff Member

    # of Dives: 500 - 999
    Location: West Palm Beach, Fl
    3,565
    780
    113
    I'm not perfect, but I've heard that the eddy current testing really only works onthe older, 6498 alloy. The newer alloy, 6061, marked "3AL" on tanks, is not designed to be used with standard eddy testing. somehow, the metal is designed in a way that the machine can think are cracks, but really aren't. However, many shops still charge for the standard testing as a way to get money. I don't know how true this is, just what I've heard. So yes, please tell us original hydro date and all that nifty stamped stuff on the crown. :)
     
  5. spectrum

    spectrum Dive Bum Wannabe ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: The Atlantic Northeast (Maine)
    11,366
    809
    113
    Yea, 3 failures sounds like the original inspector was out to lunch. They should be able to show the problem to you. The 1 cylinder I did see fail an eddy current test did have a visible crack.

    They need to demonstrate the failure or replace the cylinders. If they don't coperate contact their certifying agency.

    Pete
     
  6. MMac

    MMac Guest

    # of Dives: 200 - 499
    Location: Fresno,CA
    20
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    One tank has 5/80 date, E6498. The other I sent to PSI for them to test. They said three people tested it and it failed all three times. I asked for a report by graph and my tank back. I haven't recieved either for five months. I've talked to the original shop about replacement and they say that they being trained by PSI standards my tanks are cracked.
    My problem who is telling the truth or is it a testing problem. There should be some standard in testing. I've seen one shop do the test from the beginning to end.

    It is very frustrating
     
  7. MMac

    MMac Guest

    # of Dives: 200 - 499
    Location: Fresno,CA
    20
    0
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    Who Is the certifying agency?
     
  8. Nemrod

    Nemrod Solo Diver

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    No, no, no, NO and NNNNNNNNOOOOOOOOOOOOO.

    I have in fact do have eddy current and other non destructive testing training and use it in my job.

    The eddy current testing requires competant application and sufficient training and is highly subjective. The first shop most likely does not have a clue as to what they are doing.

    You might as well junk those tanks--good ore bad---pass or fail--they will give you nothing but grief every time you try and get them filled or VIPed. They are so cheap--why bother with all the fuss---get some new tanks.
    This is an area of vast misunderstanding and urban legend rules the day, ignorance slowly exudes it's darkness across the planet and I fear the internet rather than acting to spread information only promotes misinformation.

    N
     
  9. DiveSite

    DiveSite Nassau Grouper

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    As the photo in THIS LINK shows, 3AL is stamped from the factory on tanks that were made out of the 6351-T6 alloy, not just the 6061 alloy. There is no 6498 alloy (that i'm aware of). I believe the 6498 that you speak of is an Exemption or Special Permit number. The Visual Plus 3 tester WILL in fact test the 6061 alloy. BUT with that being said, it is very UNLIKELY that a 6061 alloy tank will have a neck crack.
     
  10. JahJahwarrior

    JahJahwarrior Solo Diver Staff Member

    # of Dives: 500 - 999
    Location: West Palm Beach, Fl
    3,565
    780
    113
    ^ if the OP junks his tanks, should he ask the shop for a discount on purchasing new ones? They stole his tank apparently, so they should give him a pretty good discounton a new one! :) When my tank was hydroed, I asked for the test data. When it failed VIP, I asked for the test data. Both times it was given to me, and my tank was returned. Nothing stamped out, no holes drilled, nothing. (currently, it sits by the trashcan, where I see it and wish for a good deal on a steel tank. tanks are a beautiful think, sleek and sexy.)


    (if anyone took anything of mine for a simple test and still won't show me test results or give me my product back after 5 months, well, obviously they've stolen it. They have no test results to show and nothing to prove the tank was destroyed, and no contract to show they had the right to destroy the tank, yet the tank is nowhere to be seen. Obviously, the tank has not eloped, so it must be stolen.)
     

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