tmassey
Contributor
I just picked up a set of aluminum 72’s. I thought they were AL80’s, but they’re not. They’re 6.9” diameter 2475 PSI tanks. A bit of research seems to indicate that these were possibly the first commercially available aluminum tanks, they did not stick around long and are not fondly remembered. They were derisively called Floaties because even full and with a regulator they had a tendency to be positively buoyant.
My question is: do these tanks have any utility for a modern SCUBA diver?
Please note that I am fully aware that these tanks are made with 6351 aluminum, that 6351 suffers from sustained load cracking and therefore has a greater than 0% chance of rupture, that they require a hydro with a visual eddy test, and that the vast majority of dive shops will not fill them. Ignoring all that, once all of that is done and the tanks are full, what task can they do? (‘Besides that, how was the play, Mrs. Lincoln?’)
Single-tank backmount doesn’t make sense. I am a technical and cave diver, so I have a place in my inventory for both deco and stage bottles. I doubt notably floaty tanks would make good stage bottles… Maybe deco bottles, where you won’t be moving anywhere once you use them? Something like EAN50 where you could use the volume?
I don’t have much into them, and I will have to put something into them to make them usable. So I’m not really looking to spend money just to use a tank poorly-suited to the task. Is there any way that this tank can earn its hydro test?
And this is Scubaboard, so feel free to make all mailbox/light/bell suggestion or “ship them to me for proper disposal” jokes you want — I can’t stop you anyway — but I really am looking for suggestions that will prevent the destruction of these tanks.
My question is: do these tanks have any utility for a modern SCUBA diver?
Please note that I am fully aware that these tanks are made with 6351 aluminum, that 6351 suffers from sustained load cracking and therefore has a greater than 0% chance of rupture, that they require a hydro with a visual eddy test, and that the vast majority of dive shops will not fill them. Ignoring all that, once all of that is done and the tanks are full, what task can they do? (‘Besides that, how was the play, Mrs. Lincoln?’)
Single-tank backmount doesn’t make sense. I am a technical and cave diver, so I have a place in my inventory for both deco and stage bottles. I doubt notably floaty tanks would make good stage bottles… Maybe deco bottles, where you won’t be moving anywhere once you use them? Something like EAN50 where you could use the volume?
I don’t have much into them, and I will have to put something into them to make them usable. So I’m not really looking to spend money just to use a tank poorly-suited to the task. Is there any way that this tank can earn its hydro test?

And this is Scubaboard, so feel free to make all mailbox/light/bell suggestion or “ship them to me for proper disposal” jokes you want — I can’t stop you anyway — but I really am looking for suggestions that will prevent the destruction of these tanks.