Remove liner from LP72

[klauricella]

Finally got around to bring a set of double lp72s to shop to get hydrod and vip. When I showed up they had passed hydro but they had put put them back together. When I was asked how I wanted the manifold set up I mentioned that I dove with a double hose and then there was the uhoh this tank has issues. Seems the liner in one has put off and there is some flash rust, then they wanted to sell me another 72 they had because they wouldnt pass mine. Has anyone successfully removed the liner by tumbling, I heard about using sheet metal screws. Would like to us this tank after paying to get in inspected.

Thanks
Kevin

 

[james croft]

Is the tank valves 3/4" or 1/2" tapered pipe thread? Either way I would just take the tanks and set it up myself if it has already passed hydro. But look into the tank yourself to make sure that the liner is coming off. If so there could be rust underneath but it sounds like they may be trying to hoodoo you. It is a PITA to tumble out a liner. Some have done it but if you have a liner that is popping off it may be just as easy to pick up a different tank. I buy steel 72's very cheaply. (5 to 25 bucks). I like the 3/4" valves as they are easier to work with and take apart.

Flash rust is not a big deal but I would want to see it first hand. If it is present then the liner has gone bad and it could be a legitimate issue. This kind of crap is why I normally never go to a dive shop for a hydro. Most just send them out somewhere else and tack on an additional charge. I find a decent hydro shop and then viz my own tanks.

 

[NAM001]

OP pease clarify something for me.. the tanks passed hydro, and after doing so the shop says oh oh liner problem, because you use a DH reg. The iliner issue should have been caught on the inspection prior to the start of the hydro test.....

 

[Stoo]

As James said, odds are, the LDS sent the tank to a hydro facility... probably a fire safety place or something... and they have a somewhat different outlook on these things. A tank can be quite badly rusted and still pass a hydro, oddly. Many hydro facilities will perform a "visual" (i.e. look for damage to the tank etc.) prior to the hydro, but not always.

I always understood that liners were like the kiss of death in a tank, since they can actually hide all sorts of serious corrosion. Replacements that aren't lined can usually be found pretty readily.

 

[Conshelf]

Get a second opinion. Rust/liner is okay as long as it does not impede the inspection in any way or hide an corrosion beyond the allowable limits. If it is flaking you can always tumble it to remove the bad parts. In Canada the hydro facility is required to do a visual inspection. This is the one that matters and is required by Transport Canada - DOT in the US. However good luck getting a fill without a current visual. Get yourself on a PSI course and get certified to do your own inspections.

Sent from my Nexus 4 using Tapatalk

 

[1bubbleoff]

OP-

IF..the tank has a liner...I suggest a few thoughts. First and foremost...the liner does NOT have to be removed ...in its entirety. Simply tumble the tank enough to remove any liner bubbles... the object is to be able to determine corrosion/pitting issues in regards to the visual inspection. As long as the VIP inspector has the ability to examine the possible issue area within the failed liner, he can make a determination in regards to pitting and integrity. The entire liner need NOT be removed. That being said....SS deck screws WILL cut liner....but be prepared to leave it rolling for quite some time lol... I suggest a clean up tumble using a decent semi aggresive ceramic media in order to determine the corrosion under the liner bubbles...once you can SEE the depth of the issue...decide from there. JMO.
Do yourself a favor....get educated. Read, learn, ask questions of KNOWLEDGABLE sources...note I didn't say.."ask questions of your hydro staff".....unfortunately it has been my experiance that MOST..not all...but most...are to a large degree ignorant of the truths regarding steel tanks, and liners. After my second LP72 was failed... WRONGLY.... ( ummm...never heard of a Sustained load cracking issue in STEEL....) and XXXXXX ed out all the markings without asking...and condeming perfectly good tanks...I went the get myself "ed-u-ma-kated" and PSI certified route. Talk about ALOT less hassle....now I KNOW my tanks are good...instead of wondering.


Bubs

 

[klauricella]

Thanks for the replies, the shop I took it to does do there own hydros the other shop in town sends theirs out to the local fire safety place and they with not hydro any tanks steel or aluminum older then 20 years. I learned awhile ago it is no use to argue with local shops because they do know everything there is too know and all that happens is I get ticked off, bad for my blood pressure. I do have my own tumbler so may try to get rid of liner to make things easier just want to make sure the screw thing wasnt a waste of time. I was given an older compressor just have to get time to rebuild it then a may never go into a dive shop again.

Kevin

 

[Conshelf]

OP-

IF..the tank has a liner...I suggest a few thoughts. First and foremost...the liner does NOT have to be removed ...in its entirety. Simply tumble the tank enough to remove any liner bubbles... the object is to be able to determine corrosion/pitting issues in regards to the visual inspection. As long as the VIP inspector has the ability to examine the possible issue area within the failed liner, he can make a determination in regards to pitting and integrity. The entire liner need NOT be removed. That being said....SS deck screws WILL cut liner....but be prepared to leave it rolling for quite some time lol... I suggest a clean up tumble using a decent semi aggresive ceramic media in order to determine the corrosion under the liner bubbles...once you can SEE the depth of the issue...decide from there. JMO.
Do yourself a favor....get educated. Read, learn, ask questions of KNOWLEDGABLE sources...note I didn't say.."ask questions of your hydro staff".....unfortunately it has been my experiance that MOST..not all...but most...are to a large degree ignorant of the truths regarding steel tanks, and liners. After my second LP72 was failed... WRONGLY.... ( ummm...never heard of a Sustained load cracking issue in STEEL....) and XXXXXX ed out all the markings without asking...and condeming perfectly good tanks...I went the get myself "ed-u-ma-kated" and PSI certified route. Talk about ALOT less hassle....now I KNOW my tanks are good...instead of wondering.


Bubs

Couldn't agree more. Did the same. Have tanks dating back to 62.

Had a shop try to fail a mid 90s aluminum claiming a single cracked thread. Catalina themselves said highly unlikely. Did a visual eddy but no actual visual. Took to another shop and all it was was where the bottom most thread started from the actual manufacturing process. 6061 alloy was never susceptible to sustained load cracking.

 

[kwinter]

Sorry, I couldn't disagree more. I won't pass any tank with a liner. Tumbling to remove just the bubbling areas is not enough to put my arse on the line. I can't certify what I can't see.

But as someone noted, the good news is that unlined 72s are readily available and cheap. Maybe not $5, but I've never paid more than $35 except one for $50 with a fresh hydro and filled with trimix.


iPhone. iTypo. iApologize.

 

[rjack321]

Get a second opinion. Rust/liner is okay as long as it does not impede the inspection in any way or hide an corrosion beyond the allowable limits. If it is flaking you can always tumble it to remove the bad parts. In Canada the hydro facility is required to do a visual inspection. This is the one that matters and is required by Transport Canada - DOT in the US. However good luck getting a fill without a current visual. Get yourself on a PSI course and get certified to do your own inspections.

Sent from my Nexus 4 using Tapatalk

PSI certified inspectors are taught not to pass any lined tank. Either get the liner out so the structural metal can be inspected in its entirety or the tank fails, end of story. No partial removal, gee it wasn't pitted so there underlying metal just "shoulda" been fine...