Long term stored oxygen in Ali80 still safe to use?

[bork-it]

I have an Ali80 filled with 80% oxygen, it's been filled with the same o2 for about 8 years, not going to be using anything soon, but wondered if it's still safe to use if I wanted to?

 

[Eric802]

Not sure if the oxygen concentration makes a difference, but last year I used an AL80 that was last filled in the mid-1990's. That was plain air and it was just fine.

 

[broncobowsher]

If it was filled properly, it is fine. If in doubt, analyze. The only possible reaction over the past 8 years would be oxidizing the aluminum. Do you hear sand rolling around inside? That would be bad. Nothing could have been added. The 20% of inert will still be inert. The 80% of oxygen, still oxygen. Only possible thing is the oxygen react and make aluminum oxide, which is a solid.

 

[LCoolio]

If it was filled properly, it is fine. If in doubt, analyze. The only possible reaction over the past 8 years would be oxidizing the aluminum. Do you hear sand rolling around inside? That would be bad. Nothing could have been added. The 20% of inert will still be inert. The 80% of oxygen, still oxygen. Only possible thing is the oxygen react and make aluminum oxide, which is a solid.

If my highschool chem still holds up, you'd also get a decrease in O2 percentage when testing due to it reacting with the AL to make the Aluminum Oxide.

 

[SetheryJ]

It's super dangerous, you should send it to me immediately so I can dispose of it

 

[bork-it]

If my highschool chem still holds up, you'd also get a decrease in O2 percentage when testing due to it reacting with the AL to make the Aluminum Oxide.

I did analyse it, reading showed 79%.

It taste ok, the Marinox we have is in Ali cylinders and thats kept around for long peroids of time, so I'm going to assume it's safe.

 

[MidOH]

The O is fine.

[But what about water, corrosion, or the dead cricket that the last VIS guy left inside?

It's $30 of air. I'm a nonsmoker, so maybe I'd have it drained and refilled for peace of mind.]

 

[broncobowsher]

The O is fine.

[But what about water, corrosion, or the dead cricket that the last VIS guy left inside?

It's $30 of air. I'm a nonsmoker, so maybe I'd have it drained and refilled for peace of mind.]

The same ones that get in there after you drain a perfectly good tank and have it refilled poorly, because new is better?

Given the state of customer service today compared to 8 years ago, that old fill is probably a better fill.

 

[Dr Simon Mitchell]

Not sure if the oxygen concentration makes a difference, but last year I used an AL80 that was last filled in the mid-1990's. That was plain air and it was just fine.

Hi Eric,

At least some degree of caution is warranted, especially if you are dealing with a steel cylinder. I had previously heard stories of this nature and always wondered if they were apocryphal, but then this (see below) got submitted, and we published it just a three months ago:

Unfortunately I can't share the entire paper with you because it is under a one-year embargo for members of SPUMS or EUBS, but in December it will be released on PubMed Central. However, I will invoke editor's privilege and show you a photo of one of the cylinders (because it is an important educational / safety point!!!).

The one from the other case did not look so bad.

Simon M

 

[Cthippo]

Al tanks are safer for this because the metal is so much mo reactive than steel and forms a passivation layer of oxide almost immiedatly. This layer seals the surface from reacting any more. Steel usually does this as well, but much more slowly, and iron oxide is more permeable than Aluminum Oxide so the reaction can go deeper and consume more oxygen.