Hi guys - since I can't get any kind of a decent answer out of Sears I thought I'd ask you what your opinions are on this situation:

I got a 30 Gal Craftsman air compressor about 2 years ago. I use it very infrequently - maybe once every couple of months. I used it today, and while draining the tank after using it I noticed that the water draining from the drain valve appeared very dark. Upon closer examination it appeared that there was rust in the water.

This has never happened before - the water is usually clear or sort of a milky color. I turned the compressor back on and let it run for about 10 minutes with the drain valve opened, and no additional water (or rust or what ever it was) came out.

Should I be concerned? I know that rusty tanks can be dangerous, but I'm not sure if this is cause for concern or not.

Sears was of no help whatsoever. They wouldn't answer any of my questions over the phone - they just said to either bring it in to a service center or they'd send a tech to my house - for a nominal fee of course...

Any input / suggestions / ideas? Thanks....

 

All mine will usually have a little rust in the water, as do most of the ones I have been around. I wouldn't worry. Just try to keep it drained.

 

The oxygen in the air interacting with moisture is what causes rust. if you are familiar with Boyles Law, well, never mind....but when you put that oxygen under pressure, it speeds the process, causing corrosion to form faster. It shouldnt be an issue unless you let the tank sit with a pressure load for loooong periods without draining and recycling the air in the tank.
The only real test of wether the tank is unsafe is a hydrostatic test, which can be performed at most fire equipment supply outlets and used to cost about $20 to have done.
If it was just discoloration and no flakes or indications that the metal has been eaten into, I wouldnt worry about it, just make a habit of draining the tank on a regular basis whether you are using the compressor or not.

 

I second the hydrosattic test. Industrial gas cylinders (nitrogen, CO², medical oxygen) get it every 5 years, as well as scuba tanks. Also, scuba tanks have to pass a yearly visual inspection where a tech will depressurize the tank, unscrew the cylinder head and take a peek inside. The techs look for cracks, oxidation (aluminum tanks), and rust (steel tanks). Wouldn't be a bad idea to do that to your compressor tank.

 

I "third" the hydrostatic test- if you've ever seen one of those buggers going boom you'll want it checked regularly.
After the test dry the tank and apply some corrosion preventing coating. (You will need to tumble the tank to do so)

AlpineRAM

 

Regardless of how much or how little you use a compressor you can extend its life by years doing the following:

ALWAYS drain the tank
use a filter that you can seal using plumpers tape etc


synthetic oil and change it twice a year (based on home use)

You may already do these things.

Synthetic compressor oil is expensive but if you consider the tiny amounts requred its very cheap insurance. Its major benefit is protectioin at higher temps than dino- a big deal in a smalll compressor like yours.

Keeping anything from being pulled into the cylinders is an overlooked part of the equation. Over time the wear from poor filtration will degrade performance/shorten life.

These things may sound picky, but there is a reason my compressors outlast my co workers by three to one, and its not because I am good looking.

I have an Emglo portable and after 6 years of use every week it still runs like new. The other guys have had two, three units in this same time period at almost 300 bucks a pop. Their filters suck, they never drain the tank and do the oil once a year.

 

I have run compressors of various sizes for years and when used a lot, drain the tanks daily. Have never had a tank problem.
I am curious about something as I have been thinking about doing this with a couple of older compressors. I know that tumbling to clean them out is the best idea, but what if the tank were drained and dried and a quart of rust neutralizer was poured into the tank and sloshed around, then drained out. Air dry the inside with warm air and drop in a quart ot zinc chromate primer (or similar) and slosh that around, drain the remains out and let it dry well. What are the pros and cons of doing this?

 

I have had my compressor for about 20 years and get all sorts fo garbage out of the tank i wouldnt worry about it just use it more..

if your going to do that i would just tumble it for a while to get any scale off and dump some por 15 in and roll it some more and be done with it.

 

well, uneven, uncertain cleaning, the primer having thick/thin spots, not being sure if you removed all the corrosion, no control over the humidity level inside the tank while it was drying and being primed and no way to tell how deep the corrosion has gone bef ore you cover it with paint..................
I'll think of a few more if you want me too..........................

 

Everyone is taking this too far. It's NORMAL to get a little bit of stale, nasty water out of a compressor. Especially one that has been sitting with moisture in it. Drain it, use it, and drain it again after you use it each time from now on. Simple.

 

Charliez, we covered that.... but if there was ANY scale or flakes, indications of metal or whatever in teh water draining out, a hydrostatic test could literally be a lifesaver....