Oxygen Clean Tank

[FishDiver]

I have two tanks I would like to have set up for nitrox fills. They just passed the visual and hydro last month so they are in fine condition. My LDS charges $60 to oxygen clean and certify each tank. This sounds awfully high to me.

Is it safe and simple to clean the tanks myself?

Is it possible to buy the nitrox certification stickers without having a dive shop do the work?

Are there any special products needed to clean the inside of the tank? I know I can buy the oxygen compatible o-rings.

 

[scubanimal]

Fish Diver,
There is a lot more to having an O2 clean tank then just "cleaning" the tank. The entire valve assembly must be cleaned as well. Proper o-rings installed, any non-O2 compatible part replaced in the valve. Each time you have a VIP you will be required to have it O2 cleaned.

For just nitrox 22-40% that is only required if you have your tanks filled by partial blending (100% O2 added then topped off with air). Membrane fill methods only require a normal vip. I assume you want to know how to do this for use with partial blending?

 

[hunter991]

There might be a o2 technician class you can attend through your local dive shop but at this stage of the game I would suggest staying away from doing it yourself. I do it for customers but I honestly sort of dread it. It is alot of work and theres a good bit of risk involved if you do it incorrectly.

In short it can be done but you need to know what you are doing before you attempt it.

Brent

 

[pescador775]

Fishdiver, there are several opinions on how to clean a tank and valve. Truly simple in concept but may require some tools and experience. The valve itself is no more complex than the faucet in your sink. However, there is a special wrench that looks like a flat blade with gap in center. I made my own. It is used to remove the grip. There is a packing inside which employs a teflon washer or O ring on the stem, rarely both. There is also a valve seat. The packing and stem are removed with a box wrench. The valve seat is spun out with a flat blade screw driver. New valves are usually good for O2 but used valves are not, almost all contain some lubricant. In the past, there has been some discussion as to which valve seats are good to go and which might be eroded over time by O2. I believe this concern is overblown for purposes of PP filling and general Nitrox apps. Use detergent and fresh water to clean the parts. Blow dry with compressed air. Replace the O ring, if applicable, with Viton or EPDM. An alternate method is to soak the parts for 2 minutes in Ensolv, an oxygen service solvent. Any lube should be the white stuff, Christolube.

The tank is cleaned with the same detergent, usually Dawn or Simple Green. Put some marbles and detergent in the tank, cap off and roll around your yard. Rinse and air dry. Lube new Viton O ring with white stuff.

There is quite a bit of physical work in DIY tank cleaning. However, with Ensolv and a tumbler machine, the whole thing can be done in an hour or less. The physical stress is confined mainly to wrestling with the tank and dumping the contents.

 

[pescador775]

About Ensolv, this stuff is expensive but indispensible to someone like me. Personally, I think detergents are marginal for this purpose. I prepare a cylinder for oxygen service by pouring in a quart of Ensolv, sloshing around and dumping, followed by air dry to remove any odor. There is no flash rust, none of the usual crappy chores. The solvent is not lost, just set aside for general purposes, and there are plenty of uses for it, I'll warrant. There is no scrubbing of the valve. All internal passages are cleaned by short submersion in Ensolv. Just don't wet out any plastic, but teflon is no problem.

 

[FishDiver]

It sounds like one solution may be to clean the tanks, buy new O2-compatible valves, and save the old valves as spares for air tanks.

 

[pir8]

Don't forget that when your LDS cleans your tank it is also certifying it so that any other shop could also fill it safely. You are not qualified to do that without training.

 

[pdoege]

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