Passed hydro, failed vis-galvanized

[scubafanatic]

....guess I'm wondering about the value of this tank in question, relative to the amount of $/labor hours involved in refurbing it?

 

[Can't swim]

This might be worth a read........

http://www.luxfercylinders.com/downloads/docs/scubaguide.pdf

 

[halocline]

I have looked into the tank and it does look like a coating of some sort and it is white in color. The impression I am getting from the above replies is just take it somewhere else where they are not afraid to do a bit more work (like tumbling) before condemning it.
Does this sound like a good way to go?
Oh, thanks for all the replies above, I really appreciate them.

If it was the shop that told you the interior is galvanized, well, that gives you an idea of their expertise.

 

[halocline]

This might be worth a read........

http://www.luxfercylinders.com/downloads/docs/scubaguide.pdf

It is an interesting guide to read, but remember that the tank in this thread is steel and that guide is only about AL tanks.

 

[ShabbyLeo]

If the original poster could give details about the original tanks brand/size/manufacture date/SN it could help; maybe just post all the stamped data since not all tanks are created equal.

 

[Aigtbootbp]

The tank is a US divers made in 1959. It has a 1/2 neck but the valve is good and I want this tank as part of a vintage diving set I am putting together.
Anything that might help?
Thanks again

Oh, it is a 72 CuFt rated at 2250 PSI. 6.9" diameter 23.5" tall.

 

[captain]

The tank is a US divers made in 1959. It has a 1/2 neck but the valve is good and I want this tank as part of a vintage diving set I am putting together.
Anything that might help?
Thanks again

Oh, it is a 72 CuFt rated at 2250 PSI. 6.9" diameter 23.5" tall.

I haven't ever come across any coated 1/2" valve 72's but I have 2 coated 3/4" 72's.

 

[Scared Silly]

Several of the posts contain misinformation notably these two:

Galvanizing is a coating that is over the steel. If this coating is damaged and the steel is rusting, there is no way to check the extent of the rust withour stripping the coating off. If this were exterior on the tank (think of paint), then you could scrap it off ro make sure there was no further rust and repaint it. On the interior there is no way to remove the galvanizing around the suspect area to insure that the underlaying metal is clean. Even tumbling the tank will do no good for this.

The only cylinders that ever had a galvanized or zinc coating were home brewed attempts that typically failed miserably. Such cylinders are few and far between. That said they should be rejected and no attempts to remove the coating should be attempted. That said and described below and by others removing legal coating is an option.

BTW If the person doing the vis can not tell the difference between epoxy coating and galvanization I would find a new shop. Of course before hand talk to the owner and tell them why you are looking for a new shop. Oh yeah, ask for your money back if they tried to charge you.

A dive shop employee (with a current PSI cylinder inspector certificate) DOES have the authority to "condemn" a cylinder to warn others of a potential danger that could be caused by pressurizing the cylinder. However, due to personal property laws they cannot make the cylinder unable to hold pressure. So, they can stamp out the numbers on the crown, but they cannot drill a hole in the cylinder or damage the threads.

A PSI inspector has zero authority to condemn (XXXX out the serial number) a cylinder without explicit notification by the owner. Without doing so is destruction of private property as the cylinder is now illegal to fill and would make you liable for a replacing the cylinder. The reason being is that a scuba vis is an industry inspection. So unless notification is given to condemn which includes XXX out the DOT markings you do not want to do it.

In other words get the owner to sign a waiver what will be done if it fails.


Now to get back on track.

US Divers distributed cylinders with internal epoxy coatings starting in late 50s the initial coatings were white. (Hmmm the OP's cylinder was made in 1959, is white inside, and has US Divers marks on it). Cylinders with such liners should be inspected carefully. If there are signs of corrosion the CGA recommends that the liner around the corrosion be removed and the corrosion be assed.

To remove the liner tumble with aluminum oxide chips. It is not necessary to remove all of the liner just around the area with corrosion which can then be inspected.

I should add that such a cylinder - corrosion with an epoxy liner that is can not be assessed should be rejected (NOT condemned). It should only be condemned after tumbling and the corrosion has been clearly assessed and has failed. Again I would not condemn the cylinder without first talking to the customer. If they did like my assessment I would simply record my inspection and give them the report.

 

[regtechkidd]

Ok.....so.....There seems to be a little confusion. Here you will find two links. One is from a representative of PSI (which is a DOT recognized cylinder inspection training agency) which states a cylinder inspectors obligations. The other is the CFR section pertaining to condemnation of SCUBA cylinders.
Facts & Fictions
http://edocket.access.gpo.gov/cfr_2006/octqtr/pdf/49cfr180.207.pdf

 

[redacted]

Ok.....so.....There seems to be a little confusion. Here you will find two links. One is from a representative of PSI (which is a DOT recognized cylinder inspection training agency) which states a cylinder inspectors obligations. The other is the CFR section pertaining to condemnation of SCUBA cylinders.
Facts & Fictions
http://edocket.access.gpo.gov/cfr_2006/octqtr/pdf/49cfr180.207.pdf

Please point out the confusion. As I read these, a scuba cylinder undergoing requalification is vis'd and hydroed and may be condemned if it fails. A dive shop filling a tank and conducting any visual inspection it is required or sees fit to conduct has no such authority to condemn a tank.