Question about dormant tanks.

[Rekcals83]

The other day my cousin told me that I could have his old scuba tanks from when he was a kid. He only dove with them a little bit in his pool, but here is the catch.... they've been sitting dormant (but filled if that makes a difference) since 1997 (according to the sticker on the tank).

My questions are:
1. Do tanks degrade over long periods of time when dormant? (they still look practically brand new)

2. If I needed to have them refurbished about how much would that run me?
2a. Would it be cheaper just to buy new ones when I get to that point?

They are full size tanks, but I don't know the brand off the top of my head (I could ask him to check tomorrow), any additional needed info please ask.

I appreciate any advice or insight you guys can give me.

 

[kwinter]

Post the markings on the tanks. That will give us a better idea. Older aluminum tanks made of 6351 alloy are best scrapped. Ditto for old tanks with tapered pillar 1/2 inch valves. Old steels might need to be tumbled, or might have liners that can make getting them inspected difficult or impossible.


iPhone. iTypo. iApologize.

 

[TheRealScubaSteve]

I'm not an expert by any stretch of the imagination, but since they're free it'd be worth having them looked at. They'll need a fresh hydro and visual inspection ($30 and $15 at my LDS). If it fails hydro ($20), you won't even need the visual. People use old tanks all the time and many have even purchased full dormant tanks without issue. It certainly wouldn't be cheaper to buy new. Just bring in 1 tank and have it checked before all of them if you're concerned about possibly losing money.

Inspection will show any signs of rust or corrosion on the inside and outside. If it is present you may have to have them tumbled, but it's not that expensive ($30 at my LDS). Cheapest price for an aluminum 80 cf tank is $160 or so online and much more for steel so it'd be worth the gamble for inspection.

 

[Jim Lapenta]

You need to find out if they are aluminum or steel. If steel they are likely just fine if they have been sitting with good dry air in them. May need a little tumble but otherwise I have steel from 1953 and 1954 that pass hydro. Aluminums could be a problem if they are the 6351 alloy. There are special procedures for testing them that some places won't or can't do and even if they can be tested and test ok some shops won't fill them. You can tell by the numbers on the crown. Steel tanks will have 3AA stamped somewhere on them. Aluminums will have 3AL stamped on them. There will also be serial numbers, DOT/TOC stamps, Mfg Date, and fill pressure. Pictures are very helpful!

 

[DEEPLOU]

I'm not an expert by any stretch of the imagination, but since they're free it'd be worth having them looked at. They'll need a fresh hydro and visual inspection ($30 and $15 at my LDS). If it fails hydro ($20), you won't even need the visual. People use old tanks all the time and many have even purchased full dormant tanks without issue. It certainly wouldn't be cheaper to buy new. Just bring in 1 tank and have it checked before all of them if you're concerned about possibly losing money.

Inspection will show any signs of rust or corrosion on the inside and outside. If it is present you may have to have them tumbled, but it's not that expensive ($30 at my LDS). Cheapest price for an aluminum 80 cf tank is $160 or so online and much more for steel so it'd be worth the gamble for inspection.

Many shops don't charge for the hydro is it comes back failed, so it won't be any investment.
aluminum 6351 alloy tanks just take to recycling center.

 

[TheRealScubaSteve]

Or make a table lamp out of it. The $20 savings for a failed hydro would buy the parts!

 

[kwinter]

I don't know any shops that don't charge for a hydro just because it failed. And if it is a 6351 tank, it must be eddy tested by the hydro facility BEFORE the hydro testing. So you're gonna pay no matter what.

Post the markings or a photo. We can't advise in the dark.

 

[Doc Harry]

Post the markings on the tanks.

 

[Rekcals83]

Sorry guys, I'm used to reddit where the mail icon lights up when I have a reply. I had just assumed no one was responding. Here are the pics of one of the tanks. The other one is the same everything... except color.

 

[runsongas]

you should be fine, says march 97 on those tanks.