reconditioning steel tanks?

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Duca

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Location
TN, USA
While talking with a buddy about the two steeel tanks I am about to purchase (used), he mentoined that if they show small signs of rust during the visual inspection that there is a proces of reconditioning. He said that it involved running ball bearings around in the tank. Is anyone familiar with this process, is it a standard practice?

Thanks...
 
Hi Duca

The tanks might need to be "tumbled". It involves adding walnut shell pieces or agregate? to the inside of the tanks and then rolling them for some time. The tanks would then need to be hydrostat tested and VIP'd because they have had some wall material removed. Talk to your LDS for prices.

Ken
 
Duca,
The tanks are usually tumbled with an abrasive such as aluminum oxide chips. The amount of steel removed from the walls of the tank is practically nil, and you can have a steel tank tumbled many, many times. Around here, you can get a tumble and hydro for about $35.
Neil
 
Thanks for the info...

The good news is that both tanks passed Vis last week... I should get them back from Hydro in time to use them this weekend.
 
they should not have passed the VIP, if they were past their hydros, because part of the VIP ensure that the hydro is current, if it isn't then the tank cannot be VIPed untill it passes.

yes I do have a PSI (profesional scuba inspection) cert. (#12115) i am also certified by TDI to inspect tanks.
 
A techinical gray area?

Perhaps my LDS did not see any point in sending the tanks off for a hydro (and charging me for them) if they were rusting through from the inside. I'm not sure if the LDS actually applied the VIP sticker to the tank until after they returned from the hydro, but they definitely gave me the results prior to sending the tanks out for the more expensive of the two tests....
 
Hello,

I've been in similar spots before and the results was NOT pleasurable. Couple of things to ask/check on, is the LDS psi certified for tank inspection? Does the LDS have a pit depth gauge (or even know what they are), did you get a paper showing all the details on the tank they vip'd? Since it's a steel tank did they inspect the threads with the scope (not the vip+ but a microscope) for cracks (yes steel tanks crack inspection in the threads). Most shops i've talked to (over 50!) didn't have a clue as to proper tank inspection. I've also been yanked around by the LDS AND the local hydro shop on tanks! I've been billed for things that was not performed on my tanks and other stuff as well.

Personaly I would never recomend buying a steel tank that had any form of rust (usualy indicates some form of mis-use/abuse) I would also recomend you take the tank to a PSI certified person to inspect the tank before you buy it.

Ed
 
I bought the tanks, took them to a certified (PADI) VIP shop, had the test performed. They passed... no rust.
The shop sent them to be hydro'd. They passed. I was given back the tanks with the appropriate markings and charged what seemed a fair rate after talking to 3 LDS's in my area.

I'm satisfied.
 
Iv'e seen new steel cylinders from the wholesale warehouse have rust. It is not only caused by abuse but by simple humidity if not kept under a minimal amount of air pressure. The only steel cylinders that dont seen to get internal or " flash " rust is Faber. They have a phosphatized coating which makes the interior extremly resistant to rust.
 
https://www.shearwater.com/products/teric/

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