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Paint on aluminum tank

Discussion in 'Tanks, Valves & Bands' started by Bigd2722, Jun 3, 2015.

  1. Bigd2722

    Bigd2722 Solo Diver

    # of Dives: 500 - 999
    Location: Winter Park, fl
    458
    90
    my 15 year old aluminum pony bottle (painted yellow) has paint bubbling on the edge. Should I scrape it off (leaving a bare aluminum spot) or leave it alone?
     
  2. tbone1004

    tbone1004 Technical Instructor ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    18,262
    10,545
    i'd chem strip it, though at that age for a pony bottle it is nearing the end of the lifespan I prefer to keep aluminum tanks, especially if it stays full all of the time as is the case with most pony bottles
     
  3. halocline

    halocline Solo Diver

    8,850
    3,179
    There is absolutely no basis for saying that a 15 year old scuba tank of any size is nearing the end of it's lifespan. If the tank is full most of the time, meaning infrequent fills, that probably means less stress on the metal than, say, daily fills. But that doesn't matter; if the tank is only 15 years old and has not been abused it has many many years of life left. A hydro test will indicate when the tank has lost enough elasticity to be considered unsafe. So, use it without any worries as long as it passes hydro, which it is very likely to do for several more hydro cycles.

    Removing the paint on AL tanks is easy, just use regular paint stripper (not acid based), a plastic scraper, and you can finish it up with some light sanding.
     
    Chugwhump likes this.
  4. tbone1004

    tbone1004 Technical Instructor ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    18,262
    10,545
    at 15 years for a pony bottle the cost of a new bottle vs the hassle of chem stripping + cost of hydro is not worth it to me.... Chem stripper plus all necessary stuff to use it is going to be at least $30, Hydro/vip is at least $40, new bottle is around $150 with valve, usually around $100 without it.

    Aluminum tanks obviously have much longer lifespans, though it is better for them if they are cycled vs left full most of the time apparently. Luxfer and Catalina have both recommended them be stored at much less than working pressure if left for any length of time. Pony bottles are usually filled and left full for a very long time.

    Paint strippers for aluminum cylinders - Luxfer: Setting The Standard Worldwide
    as far as chem strippers go, Luxfer recommends Zip-Strip
     
  5. Bigd2722

    Bigd2722 Solo Diver

    # of Dives: 500 - 999
    Location: Winter Park, fl
    458
    90
    It had a hydro just last year, so I guess it really is 16 years old. I have no intention of dumping it, unless I can find a steel pony that someone wants to trade.
     
  6. tbone1004

    tbone1004 Technical Instructor ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    18,262
    10,545
    you don't want steel ponies. When you said 15 I figured it was about due. Technically you are supposed to hydro after chemical paint removal, but you definitely have to vip. If you have a junk valve it helps so you don't have to worry about it when you do the whole tank. Alternatively if it isn't on the top crown, you can try stripping the tank just on the walls and bottom.
     
  7. RJP

    RJP Scuba Media & Publications

    # of Dives: 1,000 - 2,499
    Location: New Jersey
    13,460
    6,054
    Why would you want steel?
     
  8. Yoyodyne-88

    Yoyodyne-88 Contributor

    160
    91

    Mine is all nasty and blistered after 2O plus years, but I don't care. It's not like a steel tank that will rust under the paint.
     
  9. halocline

    halocline Solo Diver

    8,850
    3,179
    You do NOT need to hydro test a tank after removing the paint with with paint stripper. You will need a new VIS sticker. You only need a new hydro if you take off a significant amount of metal, which of course the paint stripper does not do.

    And BTW, if you're spending $30 on paint stripper for a pony tank you're getting fleeced. A quart would more than suffice, probably around $10 at home depot. The stuff you want is methylene chloride based, used on aluminum aircraft. So it's completely AL-safe. It's toxic to breathe and it's horrible on your skin, so wear thick rubber gloves and its a good idea to do it outside, with safety goggles on.

    Around here hydro tests are about $20 at a test facility.

    Sorry to pick on you t-bone, but what you are saying in this thread is simply not true.
     
  10. maniago

    maniago PADI Pro

    # of Dives: I just don't log dives
    Location: Mid-Atlantic (MD)
    899
    283
    Leave it alone. How pretty your pony bottle is on the outside is of no consequence to your ability to dive or to the gas on the inside. Go mow the lawn or do something more useful with your time (like diving!).
     

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