72's Scuba Tanks

[DA Aquamaster]

Regs aside, vinyl coatings inside or outside of tank should be removed, even if they appear to be perfect, as even a small defect can allow water to enter and be held between the tank and the coating.

The regs are simply not the issue as the liability will rest solely on the test facility if they pass a tank with a liner for the visual portion of the requalification and it then fails due to to pitting, line corrosion or widespread corrosion under the liner or coating. At that point there is no way they can prove the liner was perfect when they did the inspection, and the plaintiff and the DOT will assume the facility erred as the tank failed due to undiscovered rust under the liner.

The re-qualification stamp is also good for 5 years on the 3AA tanks in questions so the inspector is literally betting that the coating is intact, and will remain intact for the next 5 years. I'm not willing to do that and I would not *require* any tank inspector to pass a tank where it's simply more prudent to remove the liner or coating before agreeing to inspect/test the tank. Hydro facilities are not condemning tanks with the liners or coatings, they just are refusing to re-certify them until it's removed and that's pretty reasonable.

As noted previously, the newer linings are very smooth and very thin so any rust under them will be obvious - but that's not what we are talking about with any steel 72.

 

[LadyDiva]

Regs aside, vinyl coatings inside or outside of tank should be removed....as even a small defect can allow water to enter and be held between the tank and the coating.... Hydro facilities are not condemning tanks with the liners or coatings, they just are refusing to re-certify them until it's removed... As noted previously, the newer linings are very smooth and very thin so any rust under them will be obvious - but that's not what we are talking about with any steel 72.

I have to totally DISAGREE with your last sentence regarding the steel 72's. My 72's DO have a very smooth and very thin lining!

I took them to a Hydro facility and he inspected ONE of the tanks and confirmed it WAS a VERY SMOOTH and VERY THIN layer on the inside and definitely NOT a vinyl liner. He said he could NOT feel a transition from the steel to the liner and even scratched the thin liner near the mouth of the tank. He agreed to Hydro it, BUT he can NOT put a VIP sticker on it.

I chose NOT to have them done because I don't want to waste my money getting a Hydro if I can't get a VIP and fill at my LDS. I will call another LDS to see if they will do a VIP on tanks with liners, providing they don't find pitting or blisters AND have a current Hydro.

 

[Lakediving]

I am an owner of 8 72's which i bought for $50 a piece in hydro from my dive instructor. They are perfect for the kind of diving that i have been doing and I think that its cool that some still have j-valves.

 

[DA Aquamaster]

I have to totally DISAGREE with your last sentence regarding the steel 72's. My 72's DO have a very smooth and very thin lining!

I took them to a Hydro facility and he inspected ONE of the tanks and confirmed it WAS a VERY SMOOTH and VERY THIN layer on the inside and definitely NOT a vinyl liner. He said he could NOT feel a transition from the steel to the liner and even scratched the thin liner near the mouth of the tank. He agreed to Hydro it, BUT he can NOT put a VIP sticker on it.

I chose NOT to have them done because I don't want to waste my money getting a Hydro if I can't get a VIP and fill at my LDS. I will call another LDS to see if they will do a VIP on tanks with liners, providing they don't find pitting or blisters AND have a current Hydro.

There is an inconsistency here. Re-qualifying a tank involves both a hydro-test and a visual inspection - both are part of the process and he can't stamp the tank until he has done both. So, if he stamped the tank, he did a visual inspection, yet he does not want to put a scuba industry standard VIP sticker on it? That's really strange. It also suggests a lack of confidence on his part about the liner itself.

 

[Rich Keller]

Hydro facilities are not condemning tanks with the liners or coatings, they just are refusing to re-certify them until it's removed and that's pretty reasonable.

This is total BS! If the liner is in perfect condition they will test and pass them. Myself and a few others in this thread have already said they have had this done recently. The OP posted a quote from the DOT email she received saying the same thing. It is the less then reputable LDS that want these tanks taken out of service NOT the DOT! What LDS or manufacture do you work for?

 

[Nemrod]

I just will add, with any steel tank other than the steel 72, when I am in tropical garb (shorty to just a swimsuit and rash guard), I have to add air to my wing to prevent sinking, sometimes a lot. I hate swimming around with my Oxy 18 half full, no weight, no trim weight on anything, fabric plate but a negative steel tank makes me sink like a stone. Aluminum tanks, I need only a puff of air at first and I can suck the BC flat at the end of the dive, no weight required.

N

 

[aquaregia]

I took one of my 72s to several hydro places and nobody would touch it due to the liner. One guy offered to tumble it, but told me roughly how long it takes for the removal and advised me that the fee would be competitive with getting a used 85. Way more than what you were quoted. He didn't want to condemn the tank, just didn't want to touch it with the liner intact.

You'll need to replace the burst plugs if they're the lead bullets, but I guess you should do that anyway. J valves are probably fine unless you're doing pp nitrox or o2, in which cas you'll need to check on valve specifics

 

[spectrum]

He agreed to Hydro it, BUT he can NOT put a VIP sticker on it.

My first question would be if the hydro station put VIP stickers on anyone's scuba cylinders?

They do need to make a visual inspection as part of the hydro process but in my experience the LDS usually provides that actual closure of the cylinder and air fill. if I were the LDS I'd be wary of filling cylinders for the first time post hydro without looking inside. Where the LDS has the last word they usually provide the VIP for the year.

Presently we have a LDS that does it all onsite and that makes it seamless.

Pete

 

[Luis H]

He agreed to Hydro it, BUT he can NOT put a VIP sticker on it.

I am assuming that he just doesn’t have stickers because he is not a dive shop… Most hydro stations don’t put VIP stickers (unless they are also a dive shop)… they just stamp the tank. The stamp also means that it also passed a VIP.
But, we know that must LDS also require a VIP sticker.


I am familiar with at least 3 different types of internal liners in vintage steel 72’s. Not all liners are the same.

I personally own 4 steel 72’s that have internal linings. Three of them have a very thin white lining which is great. The inside is so bright that it is very easy to do an inspection. It is even easy to see scratches in the coating.

Out of the three white line tanks I have wired brush a bit of rust from the bottom of one of them. The wire brushing did the job fine, no need to tumble. The other two are perfect.

I also own one with the dark brown coating. That one is a bit harder to do a good inspection, but it can be done. I have also had to wire brush this tank on the bottom. Where the coating was compromised, the wire brushing removed the coating easily and cleared the small rust spot to a perfect shiny spot.

Both of these coatings are thin and if they are compromised by rust, it is not hard to spot and mechanically (by tumbling or wire brushing) clear the coating to clear the rust.

There are other internal coatings that are much thicker and very difficult to inspect. I am aware of a blue epoxy coating and I have heard (but have no personal experience) of the vinyl internal coatings. Thicker coatings could definitely make it difficult if not impossible to do a reliable inspection.

 

[lowviz]

...//... I am aware of a blue epoxy coating and I have heard (but have no personal experience) of the vinyl internal coatings. ...//...

So, I presume, that such tanks can never get an "Oxygen Clean" rating???