Steel Tank Purchase

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

Mndiv

Contributor
Messages
101
Reaction score
2
Location
Twin Cities, Minnesota
# of dives
50 - 99
Hey Guys,

I have a tendency to check craigslist every once in a while for any good deals on scuba gear in the area. Well I stumbled accross someone selling 4 steel cylinders for a very good price. I inquired over email for some details and the information he gave me was: Annual inspection certificate dated Aug. 96----2 of the tanks are blue and 2 are black----all 4 are marked CTC/DOT-E6498-3000----LUXFER---They all have air in them". I know the 3000 means PSI, and I'm somewhat unsure weather "annual inspection certificate dated Aug. 96" means they were first inspected in August of 1996, or they were last inspected in August of 1996... (I have sent him another email asking this and some additional info).

Now I know that there was a time in the 70's and 80's during which a bad 6351 alloy was used which promoted Sustained Load Cracking (SLC). I found some info about this on aluminum tanks, but not much on steel tanks. I know that the number E6498 has something to do with it, but I cant quite make heads or tails of it...

This might sound stupid to some of you, but as with so many of my newbie questions I would much rather have knowledgable fellow divers answer it than some random website:)

Any advice or opinions are welcome, right now my biggest concern is about the E6498 and how it pertains to the bad alloy. I will post more info as I get it.

Like always - Thanks!

PS - I know I should have them all hydro and visually inspected before use, and this is something I plan on doing.
 
...all 4 are marked CTC/DOT-E6498-3000----LUXFER---They all have air in them". ...bad 6351 alloy was used which promoted Sustained Load Cracking (SLC)....but not much on steel tanks. I know that the number E6498 has something to do with it, but I cant quite make heads or tails of it...
The number E6498 means these are ALUMINUM Tanks not steel and yes they are of the alloy that caused the problem.
Aluminum alloy cylinders - Workplace Health and Safety Queensland

One has to be very careful on the INTERNET buying used SCUBA gear. It can be stolen goods or badly mis-represented. This is a case of misrepresented as they are not steel tanks. A magnet will stick to the steel tanks.

Aluminum tanks typically have a flat bottom, Steel tanks normally have round bottoms. Your text books for your basic open water course has information on how to read the material engraved on the tank. Paper stickers are annual visual inspections and are relaced every year. So if the stickers are in fact stickers and not engraved into the metal then they have not been touched since 1996. Frankly, I would walk away from these AL tanks. Many dive shops will not fill these tanks due to material of mfg and age.
 
Last edited:
For future reference AL tanks are stamped 3AL and steel tanks are stamped 3AA. Another way to tell the difference is to look at the bottom of the cylinder. AL cylinders have flat bottoms and steel have round. There once was some AL cylinders used by the military with round bottoms. They are no longer in service.
 
  • Like
Reactions: Jax
Hey Guys,

I have a tendency to check craigslist every once in a while for any good deals on scuba gear in the area. Well I stumbled accross someone selling 4 steel cylinders for a very good price. I inquired over email for some details and the information he gave me was: Annual inspection certificate dated Aug. 96----2 of the tanks are blue and 2 are black----all 4 are marked CTC/DOT-E6498-3000----LUXFER---They all have air in them". I know the 3000 means PSI, and I'm somewhat unsure weather "annual inspection certificate dated Aug. 96" means they were first inspected in August of 1996, or they were last inspected in August of 1996... (I have sent him another email asking this and some additional info).

Now I know that there was a time in the 70's and 80's during which a bad 6351 alloy was used which promoted Sustained Load Cracking (SLC). I found some info about this on aluminum tanks, but not much on steel tanks. I know that the number E6498 has something to do with it, but I cant quite make heads or tails of it...

This might sound stupid to some of you, but as with so many of my newbie questions I would much rather have knowledgable fellow divers answer it than some random website:)

Any advice or opinions are welcome, right now my biggest concern is about the E6498 and how it pertains to the bad alloy. I will post more info as I get it.

Like always - Thanks!

PS - I know I should have them all hydro and visually inspected before use, and this is something I plan on doing.

Sorry, as the others said, those tanks are aluminum and of the suspect alloy.

First, you will have to find someone that will do an "eddy current test" and that will fill them. Those shops are few and far between.

Most places flat will not fill a tank with a 'born on' date less than 1990. It's just the way it is.

Should you decide to purchase these tanks anyway, you should not pay more than $20-$25, as they haven't been hydro'd. Before you choose to purchase them, contact local shops to see if they will do the required tests and fill them.

Source: TDI Visual Inspection Procedures book.
 
In Australia many shop won't test Ally Cylinders made before 1991, even doing a eddy. It's just becoming to dangerous for test stations.
 
With a cutting torch, they may make great win chimes.


Sent from my iPhone using Tapatalk
 
I wouldnt be very concerned about having to get someone to perform an eddie current on your AL cylinders. Someone that knows what they are looking for can find cracks in the threads of the cylinder without using a visual plus. I think many inspectors depend on visual plus and use it as a crutch.
 
Well this has been very enlightening! Thanks so much for the advice, goes a ways to prove how helpful advice from divers like you can be, so thanks again!!

I will make sure to write the seller about the problems with his tanks, and let him no. I think it wasn't bad intention on his part, as much as very little knowledge of the sport itself.

Cheers:D
 
https://www.shearwater.com/products/peregrine/

Back
Top Bottom