DOT Expiration date on early Tanks?

[MattCrunk]

A few years back I bought a vintage US DIVERS aluminum 80 (in near mint cosmetic condition) at a yard sale and took it in to my local dive shop to be inspected and hydroed. According to the dive shop owner, this tank was one of the first aluminum tanks made and it had a DOT expiration date stamped into it, which had expired. He therefore refused to inspect or fill it.

Figuring at that point that it was worthless as anything but a doorstop, I ended up selling it for $35 at a yard sale of my own. In retrospect, I'm kicking myself.

 

[spectrum]

Do you have any of the stampings that were on it?

I'm have not heard of AL cylinders with finite expiration. All cylinders have a hydrostatic test date that must be renewed and allows use for 5 years. There may be lapses in the approval cycles such as if a cylinder is dormant in the basement.

There are also a lot of older AL cylinders made with 6351 alloy that are out of favor. Procedure requires an eddy current test for these and many shops refuse to even deal with them.

Lastly many shops are self imposing a 20 year limit on Al cylinders. Unfounded, unjustified just shop policy. This may appear as a ludicrous offer such as an exorbitant ($120) VIP charge for any AL cylinder over 20 years old.

My guess is that he didn't feel like dealing with your old cylinder but want to send you home thinking you had something special. Another shop may have commissioned it without issue. The flip side is subsequently finding shops that would fill it is hit or miss for all of the same reasons. In the end you did good to get it out of your life.

Pete

 

[akdeepdiver]

Pete,
Depending how early this tank was manufactured, it could have been made before the DOT made the 3AL specification. There were some Aluminum tanks that were made under a Special Permit/Exemption. Some of these tanks switched over when the specification was designated and now are supposed to be overstamped with 3AL. But there were a few Special permits, one being SP6688, that expired and were not renewed by the DOT (Then the ICC). Those that were not renewed must be removed from service. This could have been one of them, but without the marking on the cylinder, one can not say for sure.

 

[spectrum]

Pete,
Depending how early this tank was manufactured, it could have been made before the DOT made the 3AL specification. There were some Aluminum tanks that were made under a Special Permit/Exemption. Some of these tanks switched over when the specification was designated and now are supposed to be overstamped with 3AL. But there were a few Special permits, one being SP6688, that expired and were not renewed by the DOT (Then the ICC). Those that were not renewed must be removed from service. This could have been one of them, but without the marking on the cylinder, one can not say for sure.

I kind or hedged with "I have not heard" so thanks for this information.

Pete

 

[rjack321]

As an example many (all? I forget) special permits for early Walter Kidde aluminum cylinders have expired and those cylinders are wind chimes now.

 

[JamesBon92007]

Pete,
Depending how early this tank was manufactured, it could have been made before the DOT made the 3AL specification. There were some Aluminum tanks that were made under a Special Permit/Exemption. Some of these tanks switched over when the specification was designated and now are supposed to be overstamped with 3AL. But there were a few Special permits, one being SP6688, that expired and were not renewed by the DOT (Then the ICC). Those that were not renewed must be removed from service. This could have been one of them, but without the marking on the cylinder, one can not say for sure.

Huh. I have an old US Divers Aluminum 50 that says SP6498-3000. Just above where it says "DOT" it has been stamped 3AL but that stamp was added later, after the tank was painted. The original hydro date is 6-74. It also says R19220 USD. Does this mean this tank is no longer usable? I was considering sending it out to get it hydroed.

 

[duckbill]

Are you using your cylinder in interstate commerce?

 

[herman]

Huh. I have an old US Divers Aluminum 50 that says SP6498-3000. Just above where it says "DOT" it has been stamped 3AL but that stamp was added later, after the tank was painted. The original hydro date is 6-74. It also says R19220 USD. Does this mean this tank is no longer usable? I was considering sending it out to get it hydroed.

Actually that means it is usable. See akdeepdivers post above. Now wheather or not your LDS will fill it is a totally different matter.

 

[JamesBon92007]

So, it's usable because it has the 3AL stamp?

My local LDS seems willing to fill the old Walter Kidde aluminum tanks made from the6351-T6 alloy so I guess that means he'll fill anything. Funny thing though: he was the first person EVER to fill my old (1963) steel 72 to only 2250 psi and not to 2500. The only "+" that was ever stamped on it was from the original hydro. Are they supposed to stamp a new "+" with each hydro if it's OK to overfill 10%?

Duckbill--I'm not sure if your are kidding. Besides I thought it was illegal to transport a tank that was not up to date, not just across state lines. As in: pick it up and carry it to my car would be transporting it. No?

 

[kingairpilot]

Interstate transport and interstate commerce are two different things. Unless you are transporting something for sale and not personal use, it's not commerce. Having a tank filled in one state and bringing it back to another is not interstate commerce. Filling a tankin one state, transporting it to another and then renting it to a third person...is.

Just what I recall from a business law class like 20+ years ago.

ka