Tank storage.

[Linedog]

I store my steel tanks in my unheated garage, some say bring them inside the house some say its fine where they are. Just where does condensation come from, am I damaging my tanks?

[fmerkel]

Condensation should not happen unless your fill station is lousy. All the moisture is pulled out before filling. Most tanks get water in them from residual moisture in the tank opening that isn't purged properly before filling and gets blown inside. If you fill immediately after a dive I'd pay attention to that detail. Don't expect the shop to....though they should. They generally don't want to make that loud purge noise inside.

I store in an unheated garage and have for years. If I am truly STORING a tank for a good while I bring the pressure down to 500 or so.

[boydski]

It looks like Fritz beat me to it. +1 on the above:

Most Breathing Air Compressors (SCUBA) put out extremely dry air. The last time I had my air tested, the dew point was -96°, so the air itself is not going to condensate inside the tank unless the proverbial h*ll freezes over. ;-)

The vast majority of the rust that I see inside of tanks is from water droplets that are sprayed into the tank as it is filled. This is from not blowing the moisture/water out of the valve before filling. This is easily accomplished by briefly cracking the tank valve and expelling a bit of that nice, dry air before the tank is filled.

Storing galvanized tanks in a cold garage, shouldn't hurt them, although you'll find that they take forever to dry. I insulated my garage, which helps immensely (it never freezes inside) and sometimes have to run a dehumidifier in the garage just to get the moisture out (from all the dripping dive gear).

Good Luck,

[Linedog]

It's normally a few days before I get my tanks refilled. After diving I soak my tanks then wipe and blow out the valves. Until filled they are in my car din plugs out with the opening pointing down.