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Hydro RIN ID marking is a "?"

Discussion in 'Tanks, Valves and Bands' started by crzyfish, Oct 18, 2020.

  1. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

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    I had to put a new HIN (hull ID number) on my boat as its foreign built and the USCG & State of WA decided the HIN it came with no longer met their specifications as a valid HIN for title purposes. So they issued me a new one and required me to stamp it in two places on the hull. Can vouch for the harbor freight stamps being absolute crap lol. Even in soft aluminum
     
    grantctobin likes this.
  2. broncobowsher

    broncobowsher Solo Diver

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    I had to do the same. The boat was too old and a 5-digit HIN didn't fit there system. So I made a new set of HIN plates and riveted them on. But unlike you going out and buying a set of cheap Harbor Freight stamps I have a perfectly good set of stamps at work. I suspect that if you were going to fake it, already having a set of stamps would be normal. Instead of going out and buying them for a one time use.

    A couple years ago there were some cylinders being sold off Craig's List that were stamped with "CL" for the inspector mark.
     
  3. Scared Silly

    Scared Silly Regular of the Pub

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    I can't remember when but BITD the RIN number was not stamped as part of the re-qualification date. That changed in the mid 80s???
     
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  4. captain

    captain Captain

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    Before DOT began issuing 4 digit identifiers to hydro testers they could use any symbol they wanted as an identifier. In this case the shop used a ? mark. I have several 72 from the 50's and 60's, most hydro's done before the mid 80's have various symbols between the month and year.
     
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  5. Anthony in NC

    Anthony in NC Angel Fish

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    Still using "?" in 1984?

    50's and 60's I get. I inspect steel cylinders all the time from the 1970's and they have RIN #'s on the original hydro stamp.

    That's weird.

    One of those, "By God, I been doing it this way for 30 years! Never kilt nobody!" <spit tobacco juice> hydro shops. LOL
     
  6. captain

    captain Captain

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    I have 3 tanks hydroed in the early 80's, one in 83 has no RIN one in 86 does, none in the 70's have RIN. The change was probably about 85. Original hydros on PST tanks in the 60's and 70's were done by Cochran Labs, their symbol was an L in a C. Norris used an N in a diamond.

    Notice the Norris logo at the top left.

    Norris Cylinder - History | About Norris
     
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  7. Anthony in NC

    Anthony in NC Angel Fish

    # of Dives: 200 - 499
    Location: Morehead City, NC, USA
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    You're talking PROOF MARKS, not re-qualification stamps.
    Luxfer uses the arrow, Asahi the "circle Asahi", Metal Impact the "MI", Norris the "diamond N" etc. Thos are proof marks, not a RIN number.

    The hydro shop doesn't have a proof mark, he has a RIN. The cylinder with the "?" wasn't taken back to the manufacturer for a hydro. The hydro guy doesn't manufacture the cylinder (qualify it), he "re-qualifies" it and that has nothing to do with the manufacturer.

    Manufacturers use proof marks in the place of a RIN because they manufacture the cylinder according to the specifications they submitted to DOT for approval to sell the cylinder in the U.S.

    A manufacturer doesn't "hydro test" the cylinder. Sure, everyone call it "the original hydro stamp" but it technically isn't. Manufacturers do a "proof test", which is only a stress test and doesn't measure elastic expansion of the cylinder. That is allowed under DOT regulations because the cylinder is brand new. There's no need to measure elastic expansion on a new cylinder that's never been pressurized before. The data submitted to DOT for a permit contains the cylinder expansion data, and that isn't going to change until the cylinder is used. So a formal "hydro test" to measure elastic expansion is redundant and a waste of time and resources.

    4B, 4BA, 4BW, or 4E cylinders with a max service pressure of 300 psi and water capacity of 12 lbs or less may be proof tested instead of hydro tested. DOT "4" cylinders are usually LP and propane cylinders. Scuba cylinders don't fall into that category because DOT 4 cylinders are welded-seam cylinders. So the cylinder with the "?" couldn't have legally been proof tested except at manufacture.

    When someone brings a propane tank in to be requalified, it isn't put in the water jacket and filled with water like a scuba cylinder is. The water jacket test does nothing but measure elastic expansion of a cylinder. With a DOT 4 tank, expansion doesn't matter. It's not measured or recorded. The propane tank is "proof tested". It's visually inspected, filled with compressed air to the designated test pressure, held for the designated amount of time, and if it isn't leaking, it passes and a new requalification stamp is stamped in the collar.

    Proof test VS hydro test. There's a difference. A scuba cylinders "original hydro date" is a proof test date. That's all DOT requires.
     
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  8. captain

    captain Captain

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    Be that as it may but there are no RIN's on my requalified tanks prior to about 1985. I have some tanks that are ICC 3AA not DOT 3AA. One tank requalified in 66 has ROL 4.66 stamped, the company was that did it was Roland's Sporting Goods in New Orleans, LA, one of the first places to sell scuba in the 1950's. The same tank has 7-65, 7 with the N in a diamond 70, 5 with an H in a circle 75. I have six 72's that I have owner since the 70's The hydro schedule for them put them needing hydros in 83 and again in 88, all 83 and earlier hydro stamps do not have the four character RIN, those done in 88 or later do.
     
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  9. couv

    couv Instructor, Scuba

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    ;-)

    I used to work for Roland's son (also named Roland.) He told me his father "taught" him how to dive in Lake Pontchartrain by putting him in water too deep to stand. When Roland Jr. would go to rest holding onto the side of the boat, his father would rap him on the hands with a hard rubber hose. :-D

    Now back to our regularly scheduled program.
     
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  10. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

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