Winter Tank Storage

[Raiderswim]

This is for you multiple tank guys.  If you have a full tank and will not use it until spring (3-6 months storage), do you drain the tank?  I have Aluminum and steel.  Last visual I had some particles in the AL 1st time in 4-5 years.  Now I have stell 130's and am concerned about oxidation.  What do you guys do?  Keep the tank full or drain it?  Assume regular air and helium can get expensive.  Thanks

[oldtimer]

Opinions seems to vary on AL tanks, but 30 years ago I was taught in class to drain them down to about 300 psi and store them standing up in a cool dry place. I asked this same question about steel tanks a few years back and was told that steel tanks may be store at pressure with no ill effect.

[Raiderswim]

I heard the same for AL tanks as the constant pressure can weaken the tank.  I was also told steel oxidizes at a faster rate though.

[mp4]

I have a hard time discerning the difference between storing tanks full for the winter or using them year round and filling them after use. 

[matt t.]

If you have clean dry air and follow proper fill procedures there will be no oxidation at ANY time in steel or aluminum cylinders. Pressure doesn't matter, wet air is bad no matter what the pressure is and will cause rust in steel or oxidation spots in aluminum. Among my 20+ tanks I have a range of tanks from almost empty to a couple 80's that have been full of 50% since last June.

[matt t.]

Storing a tank "full" will not weaken it. The fill cycle (stretching, heating, and contracting) or overfilling of aluminum cylinders is what "wears" or weakens a cylinder.

[ethanb]

Bring them over to my house and I'll keep an eye on them and make sure they're maintained properly over the winter.

Ethan

[ScubaDo]

Don't stop diving, problem solved ;D

[MNDiveLady]

Shush, you are giving away Ethan's trick to getting an extra supply of full tanks for the winter! 

[Raiderswim]

LET'S GO!!!!