Oops, I have rust in my air compressor tank!

[David Walser]

Last year, I got a new 27 gallon air compressor. I try to empty the tank at the end of each day, but most of the time I don't remember that task. I just noticed that I'd left the compressor on for at least a couple of months (another no no) and had never emptied the tank in all that time. (I'm a tax CPA. Things get a little hectic until April 15, when I then focus on all the other client matters that were put off because of tax season.) I just emptied the tank and noticed that the water sprayed out was rust colored. Other than doing a better job of emptying the tank at the end of the day, is there anything else I should be doing?

[Tom M King]

Every steel compressor tank I have (several) does that.

[Thomas Wilson]

On my pancake compressor, the drain valve is not at the bottom center of the tank. It is like they designed it to leave a puddle of water even if you drain the tank. I tip the tank to try to get it all. Oh yeah and the water is a bit rusty. I only use the compressor occasionally and drain it after every use.

[Bruce Page]

I agree with Tom, it’s not a huge problem. That said, I added an automatic drain valve (ADV) to my compressor and have been rust free ever since. The low humidity of Albuquerque helps too. :)
https://sawmillcreek.org/showthread.php?17659-Finally-some-air!

[Maurice Mcmurry]

A rusty tank will eventually kill a common farm and home type horizontal air compressor. I am on my third compressor tank in 40 years. Pro compressors tanks are made with much thicker steel. I hope my next compressor has an auto drain. Being vigilant about draining should help. A pressure vessel made from Chinese steel is a risk I hope I do not have to take.

[Ken Fitzgerald]

I agree with Tom, it’s not a huge problem. That said, I added an automatic drain valve (ADV) to my compressor and have been rust free ever since. The low humidity of Albuquerque helps too. :)
https://sawmillcreek.org/showthread.php?17659-Finally-some-air!

I followed my friend Bruce's advice, purchased the same automatic drain and installed one on my 26 gallon Husky single stage air compressor.

[Jim Becker]

I do not believe you have anything to worry about...that's still a relatively short period of time and "rust" is going to happen even if you drain every day 'cause it's unlikely that the inside of the tank is painted or coated with anything. My original auto-drain died before I moved shop, so right now I'm doing the "manual" dance for that at least weekly if not sooner. Note, I do not depressurize my tank as it takes a lot of run time to refill a 60 gallon unit. Right now, I just have a stop cock on an extension from the drain at the bottom and that flows through a piece of hose through the wall to the outside of my temporary shop. When I have my shop building back up, I'll invest in another auto-drain.

[Maurice Mcmurry]

These DeVilbis 5 HP compressors from Sears and Lowes were a big bang for the buck regarding air. The tanks were crap. I was also neglectful with draining. There was a recall of several pancake models in the 1990"s

481928

[Tom M King]

The water out of my little California Air aluminum tank runs clear.

[Mark Gibney]

I open the valve at the bottom of my 60 gallon tank when I get to the shop and blow out the moisture.
Draining the tank completely would mean I have to refill it to use it.

[David Walser]

Thanks to everyone who replied. I appreciate the advice.

[ChrisA Edwards]

I haven't powered my compressor off in 15-20 years. It sits with about 120psi in it and cycles about once every three days, if I don't use air, to top up the bleed down.

It's been in use in MD,FL, NJ, TN and TX, the first four being pretty humid climates.

Reading a thread, similar to this a few years ago, I decided to drain my tank.

I rolled it outside, expecting a gallon or so of water. I go about a teaspoonful (brown spot).

https://hosting.photobucket.com/albums/i452/cedwards874/Bike%20Stuff/.highres/CompressorDrain.jpg

[Bill Dufour]

A quality tank can have the drain valve off the bottom but with a internal dip tube to the tank bottom. Few have the dip tube. Best practice is to have a horizontal pipe out of the drain port to hold water between drainings.
Bill D.

[David Walser]

I haven't powered my compressor off in 15-20 years.

The reason I try to remember to shut off my compressor when leaving the shop is because of a bad experience I had several years ago. While I was out of town on vacation, a connected air hose split. I returned home to find that my air compressor had been running non-stop for about five days. I turned it off and, once cooled off, it would not run again.

[mike calabrese]

I have a small 5 gallon unit that I drain and leave the drain valve open when the unit is not needed, I don't use it every day but when I do and blow it down the amount of water that hits the floor is amazing given the actual time I use the compressor.
Corrosion in a receiver tank is simply bad news and dangerous . For compressors ( receiver tanks) the insurance policy is an auto drain and is relatively cheap given the alternatives.
FYI
https://www.vanairsystems.com/what-are-automatic-drain-valves-importance-of-automatic-drain-valves-w-compressed-air-dryers/
mike calabrese

[John K Jordan]

Wise move to power done the compressor when leaving the shop. A friend lost his shop and all tools to fire when a failure caused his big compressor to run continuously while he was out. He had left the compressor on for decades with no problem. Some years later a different failure caused the (new) compressor to run continuously but he had only gone to the house for a short iime.

The same thing happened to my 5hp compressor when the pressure switch contacts stuck and the motor didn’t turn off after it cycled. I had left the shop to feed the llamas and when I walked back I could barely hear it running from outside since the compressor is in a sound insulated closet. The switch contacts were welded together and the compressor had been running for, at most, an hour. Very hot.

Another time I was in the shop when I heard the compressor cycle when I wasn’t using it. In the closet I heard a hiss from a leak in a connection.

I have a motor disconnect toggle switch outside the closet in the main shop. i put a bright flag on it so I can see at a glance if the switch is on when I leave the ship. My plan is to to wire in a bright indicator light outside the shop door to show the state.

BTW, on the thread topic: There is a circumstance where the tank can accumulate more water than it would otherwise. The air in and leaving the tank is heated by the compression and hot air can hold more moisture than cool air.. As the air cools water can condense in the line. If the hose or piping from the compressor is long enough and positioned just “right” this water can run back down the line and drain into the tank. Some advise a long initial line running straight up then sloping down so condensed water will run away from the tank. I’ve read suggestions of at least 25’ of copper line with a water trap at the low end with a valve for draining. This length before the normal in-line water separator and desiccant dryer will help keep moisture out of the air, helpful for plasma cutting, spraying paint/finishes, etc. This, of course, may not be practical for a portable compressor.

JKJ


The reason I try to remember to shut off my compressor when leaving the shop is because of a bad experience I had several years ago. While I was out of town on vacation, a connected air hose split. I returned home to find that my air compressor had been running non-stop for about five days. I turned it off and, once cooled off, it would not run again.

[Bill Dufour]

John I have seen recommendations to slope the lines the other way so it all drains back to the compressor to one central drain. At any rate they all agree to slope the lines so they drain in some direction. I set my lines so they all slope to one drip leg near the tank. I blow off the valve at the bottom of the drip leg a few times a year, never seen any moisture come out.
My auto drain is vented to the outside. It vents every 15 minutes. I can easily hear if I left the compressor on when it blows. It is wired so it only sees power when the pump runs. That way it blows down on every startup and only blows after 15 minutes of run time or more. This way if I forget to power down the compressor it will not auto vent
Bill D

[Myk Rian]

Turning it off is fine, but you don't have to vent all the air out of it. That's just more work for the compressor.

[Scott Clausen]

I have a pancake that I hate. It leaks, noisy and too cheap to fix so I don't even bother to drain. Looking to upgrade to a nice quiet one that can handle a spray gun too.

[Alan Lightstone]

The water out of my little California Air aluminum tank runs clear.
Mine too. I did install an automatic drain valve, though, which is well worth doing.

[mike calabrese]

I have a pancake that I hate. It leaks, noisy and too cheap to fix so I don't even bother to drain. Looking to upgrade to a nice quiet one that can handle a spray gun too.

FYI you are taking a chance at serious damage or injury
again just an FYI but what you will see in the link below are the inside of compressor tanks that do not look all that corroded...just saying.
https://sites.google.com/site/metropolitanforensics/cause-of-explosion-of-air-compressor-tanks
mike calabrese

[Bruce Page]

FYI you are taking a chance at serious damage or injury
again just an FYI but what you will see in the link below are the inside of compressor tanks that do not look all that corroded...just saying.
https://sites.google.com/site/metropolitanforensics/cause-of-explosion-of-air-compressor-tanks
mike calabrese

....Yikes!

[Maurice Mcmurry]

All 3 of my horizontal tank failures were just tiny leaks that spooked me enough to discontinue use right away.

[John K Jordan]

I have a pancake that I hate. It leaks, noisy and too cheap to fix so I don't even bother to drain. Looking to upgrade to a nice quiet one that can handle a spray gun too.

I once saw a video that captured the exact moment when a tank ruptured. I don’t remember if there were injuries. If interested you might find such videos on youtube.

I used to work in a facility where we tested pressure vessels. Hydro tests made with pressurized water are safe - a rupture instantly lowers the pressure of the non-compressible water and there is very little energy involved. A pressure test with air is so dangerous we did it in an underground bunker so if the tank ruptured no one would be injured or die. Compressed air can hold an amazing amount of energy. A rupture releases it all at once like a bomb. With shrapnel.

[Mike Cutler]

I don’t know why folks empty the tank. In a properly maintained, and set up system, you really don’t want to be draining the tank.
If every time a person goes to use a compressor, they have to charge the tank, the tank is now in a saturated moisture condition, and until the air in the tank condenses the moisture, that saturated, moisture laden air is going to go throughout their system. The longer it stays in a vapor state, the less effective any moisture type filter will be.
Once the moisture is out of the tank it’s fine to leave it pressurized.
Add the auto drain and at the same time add a larger diameter pipe to the elbow tap on the tank bottom. The pipe will act as a sacrificial reservoir of sorts for the moisture that does condense in the tank and accumulate at the bottom.

[Bernie Kopfer]

I remember reading several years ago that a way to prevent corrosion and rust in a tank was to spray something into the tank (preferably when new) that would coat the tank and prevent c&r. I do not remember where I read that nor what the spray was. Anybody recall seeing this information?

[David Walser]

I remember reading several years ago that a way to prevent corrosion and rust in a tank was to spray something into the tank (preferably when new) that would coat the tank and prevent c&r. I do not remember where I read that nor what the spray was. Anybody recall seeing this information?

I thought I had seen something similar, which is why I asked the question in the first post in this thread.

[Tom M King]

I used this after repairing a leak in a tractor diesel tank, and it was the first time I ever saw clear fuel in the clear bodied fuel filter. I thought it might be good for an air tank, but never heard of it, or had the time to try it.

https://www.amazon.com/dp/B00B3I2NWG/ref=redir_mobile_desktop?_encoding=UTF8&aaxitk=69ab5c78c03669cc65ff908628d358c6&content-id=amzn1.sym.53aae2ac-0129-49a5-9c09-6530a9e11786%3Aamzn1.sym.53aae2ac-0129-49a5-9c09-6530a9e11786&hsa_cr_id=7859390290001&pd_rd_plhdr=t&pd_rd_r=cff3a232-a379-477f-a055-9a34af866bf0&pd_rd_w=c8MJB&pd_rd_wg=HlQQO&qid=1657134695&ref_=sbx_be_s_sparkle_mcd_asin_0_title&sr=1-1-a094db1c-5033-42c6-82a2-587d01f975e8