Educate Me About Buying Used Tanks Please.

[Jayfarmlaw]

Good point on steel tanks. I've attached a chart that is a good reference on the buoyancy characteristics of tanks, full and empty. Some aluminum tanks get pretty floaty empty. Diving a thick wetsuit would make it worse. Nothing sucks more than getting floaty at the end of your dive. Steel tanks may need to be tumbled at vis, so figure that into your cost.

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

 

[Storker]

There is no issue with steel tanks.

Yes, there is. Rust can very well be an issue with steels. Surface rust, both inside and outside, can be fixed, but if it's pitted, it's on its way to the junkyard.

 

[guruboy]

A hydro shop will hydro anything.

A hydro shop SHOULD hydro anything. Some will not. I know at least one shop here in Dallas that will only hydro aluminum 1991 or later.

 

[Bob DBF]

5) Try to end up with matching tanks so you don't have to adjust weights and trim based on what tank has air in it that day.

It's not too hard to adjust if you keep a cheat sheet. I picked up tanks as I could, and figured that a good price, availability, and having air trumped a slight inconvenience. I also found that some tanks were better than others for a particular dive.

A hydro shop SHOULD hydro anything. Some will not. I know at least one shop here in Dallas that will only hydro aluminum 1991 or later.

Just on principal I would be looking for another facility. I can understand not having the equipment for 6351 alloy testing, but setting an arbitrary cutoff indicates to me they may not have a well trained staff since the rest of the tanks are just another hydro.


Bob

 

[guruboy]

They just dont want to deal with the hassle, really.

 

[Compressor]

The last few threads reminds me of a local shop that refused to fill a tank that was hydroed and VIPed within a day of their refusal. I questioned the guy behind the counter: ummmm ummmm.... He could not give a reason and it basically came to be just uncomfortable filling a 20 year old steel tank. I walked out of the store and will have not been there since.

 

[Bob DBF]

They just dont want to deal with the hassle, really.

What hassle? I understand that if it needs a visual eddy and they don't have the equipment, but other than that it's just a tank.

My LDS has a sheet on bad alloy tanks and does not fill them, other tanks in hydro and VIP get filled. I suppose if the "bad" tank had a good VE hydro and a good viz came in they would probably fill it too. The problem is I don't care for people working on my gear that do not understand what they are doing.

I, personally, got rid of my two old AIs because I did not use them enough for the added expense, not because of some magical arbitrary date I made up.



Bob

 

[guruboy]

The hassle of having to check if that particular tank is 6351 alloy, the hassle of explaining what a 6351 tank is, the hassle of educating any new hires of the details, and probably mostly the risk of maybe not identifying a 6351 tank that ends up causing an issue later on and getting traced back to them.

 

[Bob DBF]

The hassle of having to check if that particular tank is 6351 alloy, the hassle of explaining what a 6351 tank is, the hassle of educating any new hires of the details, and probably mostly the risk of maybe not identifying a 6351 tank that ends up causing an issue later on and getting traced back to them.

As I said, if you have people testing your tank that don't understand their job, what makes you think they are testing your tank properly regardless of what tank it is.


Bob

 

[guruboy]

there's a difference between not knowing how to do their job and not wanting to waste their time dealing with special scuba crap when they have better things to do (like test fire equipment which actually pays the bills).

also, testing most "standard" tanks is easy. pressurize to 5/3 pressure and record the numbers.