New guy bought a used AL tank: A story

[daveg1]

Here is a better one, the local hydro place would not even test my 1988 non luxfer tank. Also all the shops around here have said they will not fill a pre 1990 al tank.

 

[oxyhacker]

That difference in working pressure, between 1800-2250 psi and 3000+, apparently makes a huge difference in failure rates. If you go back to the docket for the proposed rule change, or read the final report on it, you will see that there was quite a bit of discussion of this point, and it was decided eddy current testing was unnecessary for CO2 and med O2 tanks due to the lower pressures. Not everyone agreed, but Federal rule making is governed very much by strict cost vs benefits analysis rather than "if it saves a single life what does the cost matter" logic.

one thing that bothers me about the eddy current rules for 6351 cylinders is that applies to ONLY those used for scuba. If the cylinder is used for other purposes such the one I have which is for CO2 the eddy current test is not required. The only difference is that the working pressure of my CO2 cylinder is 1800 psi versus 3000 psi for a scuba cylinder. I am sure this is because it is only the scuba cylinders that have had catastrophic failures.

 

[Ber Rabbit]

2 years ago I went to the dump and saw an old tank in the scrap pile. Stoped the truck, pulled it out carcked the valve and it had some air left, I figured I could use the valve as a spare and sell the tank for scrap anyway.

Got home, put a gauge on it found it had 700 psi, blow it down, spin the valve off, drop a light into it, and find it is clean. Checked the stamps and it is a aluminum 72 from 1972.

Took it to the hydro shop, passed fine, put a rebuilt valve on it and took it to the dive shop, do a eddy current check, no problems. Have them slap a sticker on.

Wasn't a blue tank was it The 1972 AL80 we trashed was drilled though and I kept the valve. It passed hydro, it passed eddy current but it had two big cracks in the bottom two threads where the eddy current couldn't test but the VIP guy caught them. He told me I could take it somewhere else for a second opinion on the VIP since it passed everything else then he showed me the cracks. We sent the tank to the scrapper with some other metal.
Ber :lilbunny:

 

[DA Aquamaster]

it had two big cracks in the bottom two threads where the eddy current couldn't test but the VIP guy caught them. He told me I could take it somewhere else for a second opinion on the VIP since it passed everything else then he showed me the cracks. We sent the tank to the scrapper with some other metal.
Ber :lilbunny:

"Cracks" or "folds" would be the question with the bottom two threads, but if there is any doubt, scrapping it would be the prudent course of action.

 

[Ber Rabbit]

"Cracks" or "folds" would be the question with the bottom two threads, but if there is any doubt, scrapping it would be the prudent course of action.

There was definitely a problem, he called them cracks. I just know I could see something looked different than the rest of the threads in two spots. I fill my own tanks most of the time and getting bits of me blown off may be worth a few hundred dollars from the insurance company but I LIKE being in one piece
Ber :lilbunny:

 

[The Chairman]

When I took my PSI class a number of years ago, I was impressed with one fact. A conscientious VIP will uncover a crack at least a year before an eddy current test and at least TWO years before it becomes dangerous.

 

[Dive Right In Scuba]

I havent gotten anything from my insurance company about tanks I can and cannot fill. I think that is a garbage excuse. However, I do understand not filling some of the older tanks for safety reasons BUT dont lie, just say we dont want to take a chance or something, or its the SHOP RULE......We fill what walks in the door, if it passes proper VIP and Hydro, we have no reason to assume a faulty tank. If in doubt, never happened yet, we will ask that a new VIZ or Hydro be done for our safety. It is our choice to fill your tank, its not mandatory so I can understand some peoples, UN-informed peoples, decisions. Just dont lie and blame it on someone else!! We have an explosion proof fill station that we use, that doesnt mean I want to blow up a tank or that we will take chances, but we are taking the right steps to protect the filler IF something drastic occurs....

 

[Bob3]

One of the "best" tanks I have is from 1959; it has consistently passed hydro with zero permanent stretch.
Having spent it's entire life in fresh water & getting clean fills, it has never needed to be tumbled either.
Too bad they don't make 'em like that any more.

 

[300bar]

Sorry for the hyjack:11:

Can somebody please explane to a non US citizen what the "beep"
a eddy is never heard of it.

 

[Dive Right In Scuba]

Its an electrical current test that tests for cracks in the threads...