I was given a vintage steel cylinder. Will I not be able to use it?

[akdeepdiver]

Take it to a hydrotester, not a dive shop to be tested. 99% of dive shops send them out. If you need help finding one in your area, email me at tanktest@gmail.com and I will happily help you locate on. A Hydro shop usually charges quite a bit less then a dive shop. A specification cylinder (3A, 3AA, 3AL, etc) can remain in service as long as it continues to pass a hydro and visual every 5 years according to the DOT and the CFR's. Next time a dive shop says that they are no longer allowed for diving, ask him to show you in writing. Additionally, if the shop EVER condems this cylinder on that reasoning, and they can not prove it in writing, then they are wrong, and you have a winnig lawsuit in small claims court.

 

[duckbill]

I think I know what you're trying to say, but a couple points for clarification:

A specification cylinder (3A, 3AA, 3AL, etc) can remain in service as long as it continues to pass a hydro and visual every 5 years according to the DOT and the CFR's.

More accurate to say, a specification cylinder (3A, 3AA, 3AL, etc) can remain in service for five years from the date it passes a hydro and visual according to the DOT and the CFR's.

A cylinder's hydro can lapse indefinitely and it can still be retested. IOW, a cylinder that was last tested in 1953 can still be hydroed. Just didn't want anyone thinking that if you miss the 5 year mark the cylinder is out of service for good just because you didn't have it tested 'every 5 years'.

Additionally, if the shop EVER condems this cylinder on that reasoning, and they can not prove it in writing, then they are wrong, and you have a winnig lawsuit in small claims court.

If you are refering to a dive shop, a dive shop has no authority to "condemn" a cylinder at all, unless they are also a hydrotesting facility licensed by the DOT.

 

[50Fathom]

On a related note, I have a PST steel tank from '53, (service pressure 2150, not 2250), and it has the concave "magnum champagne bottle" bottom, which like the above tank, allows it to stand up without a tank boot, which I find pretty awesome. (I despise tank boots).

How come new steels don't come with the concave bottoms unless they're big K-bottles or the like? Or even flat bottoms? A search here turns up nothing.

Oh, I work in a shop, but I'm also a "vintage equipment" diver, so I'm fairly savvy to this stuff, and if I don't know something, I find out. Just wanted people to know that not ALL dive shop tank monkeys are helmet-wearing window-lickers.

Only most of them.

 

[duckbill]

How come new steels don't come with the concave bottoms unless they're big K-bottles or the like? Or even flat bottoms? A search here turns up nothing.

From what I understand, steels cannot be flat bottomed like aluminum tanks due to the spinning process used to manufacture them. I'm not sure how the process for aluminum tanks differs, except that aluminum is softer.

Just guessing the "bump bottomed" cylinders fell out of use for scuba due to increased difficulty of inspecting and cleaning for inpection of the four concave recesses, along with the availability of boots that stand round bottomed tanks upright.

 

[50Fathom]

A little google digging discovered it could be a trim issue as well. A company in England a few years ago made (and might still be making) concave "champagne-bottle" bottom cylinders, like my '53 PST. They indicated that it added .6 kilos to the weight of the tank, (maybe 1.25 pounds), and it was all concentrated in the bottom. This makes sense, and it might make trimming a set out difficult.

 

[50Fathom]

Here it is. Flat bottom 12L 232 bar cylinders, equivalent to HP100s:

NEW – “flat-bottomed” Eurocylinders | Silent Planet

http://www.silentplanet.info/customerdownload/press/flat-cyl-press-release-oct2010.pdf