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Yet another LP 72 question

Discussion in 'Vintage Equipment Diving' started by Basking Ridge Diver, Jan 11, 2016.

  1. lowviz

    lowviz Solo Diver ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Northern Delaware or the New Jersey Turnpike
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    There are those of us who appreciate a ready supply of 72's. Thanks.

    BRD's went for 2/3 of your asking price with a rock-solid satisfaction guarantee.
     
  2. BubbleGator

    BubbleGator Angel Fish

    # of Dives: 0 - 24
    Location:
    9
    2
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    How the heck did you get the hydros with a plus? They have no REE stamps that I know of.

    I just found an old Nemrod tank waiting on the road for the trash man last month. I know I can get a hydro test pass, but not the plus. 71cf is mo' bettah than 64.7 cf, so how the heck do I talk them into it?

    Does your guy - ah - know stuff I can pass on to my local guy?
     
  3. BubbleGator

    BubbleGator Angel Fish

    # of Dives: 0 - 24
    Location:
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    I guess I can get the old Nemrod filled to 2250, and then hook it up with a tank-to-tank equalizer and a full LP95. Not sure the exact math given the difference in volume, but I imagine when the pressure equalized you'd get somewhere between 2400 and 2541 psi on both of them - at least if the LP95 started at the full plus 2640. WAG - around 2480, which would be about the extra 10% on the Nemrod and get it close to 72 cf.

    Could be wrong. Often am.
     
  4. lowviz

    lowviz Solo Diver ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Northern Delaware or the New Jersey Turnpike
    6,873
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    Yeah.

    #1) Forget the "+rating" thing.

    Any 3AA2250 steel 72 in current hydro with a current VIP can be filled to 2800 psi repeatedly. Keep looking for a shop that will readily agree with this, it shouldn't take long to find a good one.

    Now you have a steel 80.
     
  5. BubbleGator

    BubbleGator Angel Fish

    # of Dives: 0 - 24
    Location:
    9
    2
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    Thanks. Not a ton of dive shops locally, and my past efforts have not been good, but I will inquire.

    If I lived in North Florida I wouldn't have even brought it up. :cool:
     
  6. couv

    couv Instructor, Scuba

    # of Dives: 1,000 - 2,499
    Location: 13th floor of the Ivory Tower
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    I wish I needed a few tanks.....that's a good deal-and I hate to pass up a good deal on gear whether I need it or not.
     
  7. FireMedicATL

    FireMedicATL Solo Diver

    # of Dives: I just don't log dives
    Location: Livonia, MI
    351
    75
    28
    That attitude is why I have 11 sets of doubles listed for sale right now and 30 steel 72s in my basement.
     
  8. FireMedicATL

    FireMedicATL Solo Diver

    # of Dives: I just don't log dives
    Location: Livonia, MI
    351
    75
    28
    This is copied from my post in an earlier steel 72 thread.

    --------- Post added August 26th, 2015 at 06:55 PM ----------

    Since there seems to be a lot of confusion about good old steel 72s, let us try and set the record straight.
    Liner or no liner, doesn't matter much. The liners tumble out overnight. I have never had one I couldn't remove. You will not cut into the wall enough to harm the tank in the time it takes to remove a plastic liner.
    Whether or not your LDS is capable, that is a whole different boat.
    The only thing that kills a 3AA tank is rust, inside, outside, doesn't matter where, but if you don't see rust, assume you have a good tank.
    I have hydroed at least 100 72s in the last three years and I have had ONE fail hydro, several have failed visual inspection due to rust, but just one on the hydro end. (That tank still befuddles me, it is beautiful,it must have been overpressured to the moon sometime in the past.)
    As to the plus hydro, they should not be getting one. Period. End of story.
    The Manufacturers of steel 72s are no longer in the business, there is no way to confirm an REE number.
    The PST document that is often alluded to has a misprint on the tank pressure line for the steel 72 tank. There is no other version that I have seen. With the misprint and no way to confirm it with PST, that document is invalid.
    Any retester doing this for a living is not going to risk his license to plus stamp a 40 year old scuba tank for somebody.
    If they are willing, that is on them. The problem lies in that they have no paperwork should they ever be called to point on their decision.
     
    lowviz likes this.
  9. John C. Ratliff

    John C. Ratliff Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: Beaverton, Oregon
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    Here's the problem with this notion of filling them over their rated capacity; the burst discs are not made for that. If you change out the burst discs to a higher rating, you loose their protection factor and are breaking DOT rules if they are transported over state lines or on DOT regulated highways. Besides, it still is bad policy. My advice: DON'T DO THIS!

    SeaRat
     
  10. lowviz

    lowviz Solo Diver ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Northern Delaware or the New Jersey Turnpike
    6,873
    3,552
    113
    Yes, the burst discs were changed with the addition of two recently maintained valves, see post #9.

    It is common practice to overfill those LP steel tanks to 2800 psi. Both the fill operators and diver assume some risk in doing this. My LDS will only overfill tanks that they have inspected. Both my LDS and I consider this risk to be very small relative to other risks in diving.

    However, refuting the practice of overfilling is best done with this: http://www.undercurrent.org/UCnow/dive_magazine/2005/ShouldWeDive200505.html
    Anyone who chooses to overfill steel tanks should be aware of both sides of the argument.
     
    Last edited: Jan 19, 2016

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