Avoid used LP Steel Tanks?

[schu1842]

I took the DAN O2 course tonight and my instructor is a cave diver. I was talking to him about various gear issues at a break and he indicated it was not a good idea to buy used LP steel tanks on ebay. He said many of the tanks are used by cave divers and are often significantly overfilled which may lead to failure on the next hydro test. He indicated the used HP steel tanks are a safer buy. I had never heard this before. Any thoughts?

 

[captain]

Just don't buy any from cave country if you believe what he said, but I don't believe it.

 

[Scared Silly]

Yeah I would stay way from any cave country never know what might come swimming out. That said LP cylinders do get over filled. But like any used product it is caveat-emptor.

 

[PerroneFord]

Amazing how those LP cylinders down here in cave country that are 10-20-30 years old are still passing hydro with plus ratings.

Whatever.

 

[Fotoz4FX]

Hydro testing places a 5/3rds overpressure on the tank... if it passes the Hydro, who gives a crap what any diver tries to tell you. It's good to go to at least it's specified and rated pressure. I get overfills all the time and I've been diving since 1970 - I've yet to have issue with a tank that was in Hydro (or even out of hydro for that matter... if the Hydro ran out, I'd dive the pressure down then have it serviced before using it again).

There's just too much paranoia in the world.

If DAN had their way, there wouldn't be any competition. I took the DAN CPR Instructor course and they made it sound like theirs was better than any of the others... problem is, I've had the others - DAN is no better than anyone else...

...take what you're told with a grain of salt then follow up on the truth.

 

[battles2a5]

I have a feeling your instructor has a stock of HP tanks to sell.

 

[DA Aquamaster]

There was a period where there were some reports of hydro failures and excessive rust with PST tanks, but these were not related to either LP tanks or overfills. The issue, other than rust, was with HP tanks not always being tested with the proper protocols.

In general, I would be leary about buying any steel tank off e-bay that did not have a current VIP and a recent hydro. I may still buy it but I would not pay as much money for it and that applies to HP as well as LP tanks.

There are in my opinon far better reasons to buy HP tanks that make it worth passing on LP tanks unless you happen to live in cave country where LP=HP.

 

[james croft]

I have heard the same theory before, but it is not much of an issue. You may want to get a hydro on the tanks as a condition of purchase and see how the tanks do.

 

[DIR-Atlanta]

There was a period where there were some reports of hydro failures and excessive rust with PST tanks, but these were not related to either LP tanks or overfills. The issue, other than rust, was with HP tanks not always being tested with the proper protocols.

These were the so-called "Genesis" tanks, rated at 3500 PSI, and with a 7/8" rather than a 3/4" neck thread. Introduced in the late 1980s, they were manufactured under a DOT exemption (E9791) and were only supposed to be hydro tested to 3/2 their rated pressure, rather than 5/3. Many hydro facilities, being unfamiliar with the tanks and the requirements for testing them (and apparently unable to read the test pressure, which is stamped directly into the neck - TP5250), would over-pressurize them, which would cause them to fail.

In my experience with these tanks (having owned several of them "back in the day"), the rust was usually flash rust that resulted from the tanks not being properly dried after their hydros. I would almost always have to give them a light tumbling after they came back from the test facility, but never saw any rust that I would call "serious" or "dangerous".

Note that the newer E series tanks from PST are also manufactured under E9791, and should also be hydro tested to 5250 PSI.

 

[pescador775]

DIR, aren't you guys supposed to know everything? The "protocol" that DA was talking about was the pretest or "rounding out" procedure. Even following this procedure a lot of those HP tanks have failed at 3/2. Whatever, I would not buy anything from "cave country" unless it was something rare and desperately needed.