Air Tank Rust

Automotive Onboard Air Systems
1

As many in the Great Lakes Region know, it’s been a very wet summer. Raining pretty much every other day, and therefore it’s been very humid. I drain my tank after every use, but admittedly I forget to use the drain valve sometimes. However, whenever I’d use the drain valve, I’d typically get a light mist at best. Eventually I heard sloshing in the tank. I drained the tank from full pressure this time, and still barely any water came out, though the valve froze several times upon release. I decided to tip the tank upward as I still heard sloshing, and a large orange puddle came out.

I removed the large 1-1/2" bushings from the top of my 20 gallon tank and saw this. Some of the sludge is oil. I’m not sure how concerned I should be about this, though I routinely fill the tank to 175psi. I know now I should tip the tank upward after each use, but I’m not sure if it’s already too late. Needless to say, the last thing I need is my air tank to become a second stage booster for a rocket launch, at least while I’m still using it.

-20170823_040230 by CN8815, on Flickr

2

I’ve heard some recommend putting in a small amount of anti-freeze after draining your tank but I don’t know how or where they add it.

3

Thanks. I dumped a few gallons of vinegar in the tank overnight and cleaned it out pretty well. There’s still rust stains on the tank, but no evidence of pitting around the welds or end caps. The freezing issue I’m sure had to do with all the water in the tank. At one point I couldn’t even get my horn to sound.

I guess it’s a good lesson though. Unless you have a vertical air tank, or can drain the tank vertically, there’s a pretty good chance the drain valve didn’t remove most of the water.

4

Had my share of rusty tanks

Never had any issues with leaks, but since I run drain solenoids, they’d get plugged up every now and then.

Now I only run aluminum tanks