Tanks...which ones can't be re-hydro'ed?

[JamesBon92007]

I've been reading a lot of posts concerning the old aluminum 80s and can't seem to find the answer I'm looking for, which is: what percentage of scuba tanks fail the hydro test? Or, to get more specific, what percentage of tanks made from 6351-T6 fail? I have three tanks from the 80s (two from '86 and one from '83) and I'm wondering if it would be worth trying to get them hydroed. Laguna Sea Sports gets $35 for a hydro test but it's only $15 if it fails but on top of the $35 I'll have to pay for some other tests and inspections which sound like they cold add up to around $85 or so. Basically I would like to know what are my chances of them passing the tests. I also have an old steel 72 from 1970 and the newest date on it is 1985. Does it have a better or worse chance of passing than my aluminum 80s? Am I going to have a hard time finding anyone that will hydro test them and, if they do pass, fill them?

While looking for information I couldn't help but read about the aluminum tank that exploded and severely damaged a man's hand. But I never read an explanation for why the tank exploded. The article said that the man only attached the fitting to the tank and was testing the pressure when it exploded. How much air pressure does it take to make a tank explode like that? I have to assume since the tank was there to be filled that the owner thought it was low on air but my thoughts are that it must have been full or nearly full.

 

[captain]

I've been reading a lot of posts concerning the old aluminum 80s and can't seem to find the answer I'm looking for, which is: what percentage of scuba tanks fail the hydro test? Or, to get more specific, what percentage of tanks made from 6351-T6 fail? I have three tanks from the 80s (two from '86 and one from '83) and I'm wondering if it would be worth trying to get them hydroed. Laguna Sea Sports gets $35 for a hydro test but it's only $15 if it fails but on top of the $35 I'll have to pay for some other tests and inspections which sound like they cold add up to around $85 or so. Basically I would like to know what are my chances of them passing the tests. I also have an old steel 72 from 1970 and the newest date on it is 1985. Does it have a better or worse chance of passing than my aluminum 80s? Am I going to have a hard time finding anyone that will hydro test them and, if they do pass, fill them?

While looking for information I couldn't help but read about the aluminum tank that exploded and severely damaged a man's hand. But I never read an explanation for why the tank exploded. The article said that the man only attached the fitting to the tank and was testing the pressure when it exploded. How much air pressure does it take to make a tank explode like that? I have to assume since the tank was there to be filled that the owner thought it was low on air but my thoughts are that it must have been full or nearly full.

Getting the old 80's tested and passed is not the issue, getting a shop to fill them is the issue, many just won't fill them no matter if they passed the hydro and eddy current yesterday. The just aren't worth the effort.

The old 72's last forever if kept dry inside. I have 10 the oldest is 53 years old and passes everytime. They are worth the effort.

 

[JamesBon92007]

OK, thanks. I'll start with the steel 72. It looks pretty good inside. I removed the valve from one of my aluminum 80s (made in '86) and could see a nice crack along the threads. Wow. Thanks to whoever posted the Luxfer Visual Inspection Guide link. I also have an old aluminum 50 that looks perfect inside but I haven't yet determined which alloy it's made from--the tank is simply too small to use except maybe for retrieving a fouled anchor.

Maybe I can use the aluminum 80s for extra storage with my 100 psi air compressor. I think they should be able to handle that little bit of pressure.