Death by air compressor?

[6t8dart]

I came upon a very sobering issue yesterday that could have lead to my death or serious injury. Every once in a while someone posts about an exploding air compressor, yesterday it almost happened to me.

Ten years ago I bought a wonderful craftsman professional series horizontal air compressor. It has power my air tools and even helped me paint my 68 Dart. Yesterday I was in the garage doing some general cleanup, organization, and tool maintenance in preparation my Mark D's visit in a few weeks to help me with my MK4. I have not used it in quite a few months, mainly for tires, etc, I would turn it on for a few minutes, then turn it off again. It had been leaking air so decided to clean a leaky bypass valve on my compressor to try and fix it, while I was at it, I changed the oil and did some other minor maintenance to it. I put it back together, switched it on for a minute to check for leaks...I heard hissing. I started to feel around at all the fittings, but nothing. It sounded like it was coming f on the bottom, i thought maybe the drain was leaking, but felt no air coming out of it. I pulled the compressor out from under my workbench and flipped it on its end, that's when I saw it...drops of water coming out of the middle of nowhere. It hit me that the inside of the tank must be so rusted that it ready to come apart. I started thinking about the pictures of destroyed cars and garages. I realized that I was so lucky, it could have been very bad for me and my family.

You can see the two drops n the center of this picture
IMG_3886.JPG

I highly recommend that everyone regularly drains their compressor and replace it every once in a while. I got lucky that I was listening for leaks and that I just didn't turn it on and go about my business.

[michael everson]

Mine had a similar leak at the bottom. I drilled and tapped it and put a bolt in it. Been like that for years. Bad idea?
Mike

[redline]

I am good about draining my compressor every time I use it. Now I will have to google scary stuff and consider replacing my air compressor regularly. Preventative maintenance isnt a bad idea either i suppose.

[turbomacncheese]

I replaced the garbage screw with a 1/4 turn brass valve. Actually holds a bit of water. Lucky me, Arizona isn't very moist, so even though I open it at the end of the day, it never spits any serious amount of water out.

[Mark Reynolds]

Excuse me while I go out into the garage and drain my compressor.
My son is home from college and he just purchased a 1997 Volvo 850 Wagon with a 5-speed.
He was using the compressor to today glass bead some license plate nuts and some rusty hood latch screws.
BTW the engineering on that Volvo is impressive. Have not found any body rust yet, and it was a Maine car (whereas i have swept about 10% of my 1999 Ford Club Wagon Chateau up off my driveway over the past 10 years and thrown it out in the trash)
6t8dart did your compressor ever have a drain and did you ever drain it?

[DadofThree]

This reminds me of a thread last year. I ended up buying a new one as a result.

[edwardb]

I retired my 25+ year old Craftsman oil-less air compressor just a few weeks ago for just this reason. I admittedly wasn't as careful as I should have been about draining it regularly. It was to the point where it was apparently so rusty inside it wouldn't even drain any more. Just a few drops of really rusty water. Even though I could hear sloshing around in there. No rust showing through the tank, but figured it was a huge safety hazard. Plus it sounded like an airliner taking off. I put it out with the trash and someone snatched it in about 5 minutes. Didn't even see it go. Hopefully they are just recycling it and not actually using it. Replaced it with a nice Quincy upright. Works great and much quieter. I promise I'll be more careful.

[mike223]

Most every portable pressure vessel made in the last 30 years (maybe a little longer) is stamped with a ten year expiration date - "Discard after [year]".

I think this is mainly due to DOT regs - looks like they require a hydro test certification on all pressure vessels at 3, 5, or 10 (max) year cycle(s).


I'd say a 25 - 30 year retirement plan is probably judicious for your average home duty air compressor / tank (probably near end of life for the rest of the parts anyway).

[Papa]

I installed an automatic purge system on my compressor that ensures regular (daily) purging of any fluid that collects in the tank. There is a tube inside the tank that goes to the lowest point and attaches to the purge valve. I have mine set to trigger once every 24-hours, but the valve can be set to every 5 minutes if I needed it.

[Arrowhead]

Mine had a similar leak at the bottom. I drilled and tapped it and put a bolt in it. Been like that for years. Bad idea?
Mike

Ya know I just cringe every time I think about that post, sorry Mike

[Ipassgas]

Most tanks fail like this, pinhole leak prompting replacement. It is unlikely your tank would have exploded. Your rusting doesn't appear to be at a weld.

The bomb type failures usually happen at a weld.
Either way, glad you're safe!

[first time builder]

Papa thats a great idea but must be connected to lowest part of tank, IE the bottom. I have had it on all my compressors for years .

[Papa]

Papa thats a great idea but must be connected to lowest part of tank, IE the bottom. I have had it on all my compressors for years .

My tank is designed to allow me to drain accumulated water from a bucket-level fitting. There is a tube that runs from the fitting to the lowest part of the tank. I also have a drain at the bottom of the tank, but every time I've checked it, I've only gotten a brief spray of mist, which tells me that the one higher up is working as it should.

[mcmustang]

Most compressor explosions are due to failed pressure regulation. Rust through rarely causes an explosion. The usual rust through failure is a slow leak that gets progressively worse. Regular drainage will prolong tank life, but eventually they need to be replaced. One danger signal is if your compressor seems to be running for a long period of time unnecessarily. That's when you should shut it off and find out what is causing it.

[AC Bill]

Checking the compressors safety relief valve is good practice as well. If the regulator fails, you better hope the safety valve is working.

[JimLev]

Thanks for the reminder, just did mine now.
Hadn't done it in months. Only about an ounce came out, high desert living.
Humidity is usually 10-20%.

[toadster]

wow - bumping this... I've had my air compressor for about 20 years, and I have NEVER drained it...

[billjr212]

Good thread to bump. Always something to keep top of mind. I moved my compressor to the basement a few years ago and hard piped it into the garage to a reel on the ceiling. At the same time, I swapped the awful drain valve on the bottom for an elbow and a short stretch of pipe followed by a quarter turn ball valve. Gives a bit of space for condensation to sit without sitting in the tank. It's lined up with the furnace floor drain and I go down in the basement regularly to drain. As a bonus, with the steady temperature in the room it doesn't seem to be as bad as when I used to have it in the garage.

Edit: Oh, I also plugged the compressor into a smart plug. I have an Echo in the garage and I just tell it to "turn compressor on/off" as needed. Otherwise I keep a relatively low amount of pressure in the tank (~50 psi) to fill tires/basketballs/etc as needed. I added a gauge on the copper line in the garage so I can easily see where the pressure is at anytime.

[JohnK]

When I installed my compressor a few years ago, I added an auto-drain to it. The auto-drain is plugged into the switched light circuit in the closet that the compressor is in. Whenever I use the compressor I open the closet, turn on the compressor and turn the closet light on. The auto-drain will then cycle for 5 seconds every 30 minutes for as long as the closet light is on.

[J R Jones]

Some might equate compressor tanks at 125PSI to welding, oxygen, CO2 tanks which contain much higher pressures that are more dangerous. Thankfully those pressure vessels are regulated closely and hydrostatically tested.
As mentioned by Ipassgas and MCmustang, rust creates an annoying leak before enough surface rusts to result in catastrophic failure. Industrial compressors and aircraft ground support equipment operate at higher pressures that are more dangerous.
OTOH a bad regulator would create more risk, but most modern compressors have an over-pressure relief.
jim

[cob427sc]

I have a rather large 2 piston compressor and tank that replaced an old smaller unit several years back. When I installed the new compressor I added the auto drain to it, and it's a must have hear on Cape Cod with the high humidity. Also helps keep the air tools running better and is a must have if you are spray painting. Not cheap, but overall a good investment.

[svassh]

Hmm my $50 Craftsman compressor has a leak around the regulator so I have been letting the air slowly leak out rather than opening the drain valve. Guess I need to change my habits.