2HP 20 gal 220v 30 yr old compressor pb. Repair/Replace?

[Don Morris]

Around 1980 I bought a Craftsman 2HP 20 gal 220v compressor so I could do some auto painting. Since then I've gotten totally away from that and developed my passion for woodworking. It drives all my nailers, cutoff tool, and is a great dust blaster/shop cleaner. I find I'll go a month without using it then for several weeks use it on an almost daily basis. It was in storage for 4 yrs during one overseas tour. I had it serviced at that time about 15 yrs ago. I've changed the oil periodically. After about 30 yrs of ownership, I went to turn it off yesterday and the switch had no effect. I listened for it to turn off for about one minute, the safety valve started to release, so I quick grabbed the electrical plug and pulled it out of the wall socket. Plugged it in today and it started up with the switch in the "off" position. Again, pulled it out of the wall socket. It looks like just a "switch" problem, but will the repair cost to me be about the same as a new compressor? Also, in the almost 30 years, I'm a little concerned about the tank. Surely these tanks must get a little corrosion going on in them? Is there a life span where you compressor guys say it's time for a new one? Not being experienced in long term ownership with compressors, I'm asking you guys for some guidance. Please, and Thanks!

[Jerome Stanek]

It is switch the contacts have welded closed and not breaking contact. Switches are cheap and easy to replace. My 60 gallon needs a new one for the same reason.

[Mike Hollingsworth]

I'm a big fan of the Grizzly switches.

http://www.grizzly.com/products/Magnetic-Switch-Single-Phase-220V-Only-1HP-7-2-10A/T24100 (http://www.grizzly.com/products/Magnetic-Switch-Single-Phase-220V-Only-1HP-7-2-10A/T24100)

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[Jerome Stanek]

That switch won't work on it he needs a pressure switch maybe even one with an unloader.

[Keith Outten]

Don,

Before you decide to do anything make sure you check the integrity of the tank. Everything else is second to making sure that the tank is not thin at the bottom where water would have been sitting over the years rusting the bottom of the tank. A 20 gallon tank at 90 psi can totally destroy a two car garage, it happend right here in the county where I live several years ago.
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[Mike Heidrick]

Don,

Before you decide to do anything make sure you check the integrity of the tank. Everything else is second to making sure that the tank is not thin at the bottom where water would have been sitting over the years rusting the bottom of the tank. A 20 gallon tank at 90 psi can totally destroy a two car garage, it happend right here in the county where I live several years ago.
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Do tell more about that. Never in my life have I heard of a rusted air tank destroying anything. Let me guess, they had PVC ductwork too? ;)

[Matt Meiser]

Usually they just start leaking rather than let go catastrophically but is it worth the risk? That old it's probably a fairly well made tank.

Last time I needed one I found a switch like you need at the local hardware for less than $40.

[Don Morris]

That's why I wrote inquiring about an old tank in addition to the switch. Was the tank that blew up old? Or was it just a manufacturing defect? What's the history of those of you that have had tanks for multiple years? I have a couple inquiries to companies about switches that look like they might be replacements for the pressure switch for my Craftsman, but the question about the old tank remains.

[Silas Smith]

Not to freak anyone out, but my co-worker's grandfather was killed last year when his air compressor rusted through. Apparently it shot straight up, hit the ceiling, and then deflected right into him. He worked at the desk next to me and was pretty close to his grandfather so it was pretty sad.

I don't think it is a common thing, but it is real. Check the tank integrity while you are at it.

[Michael Mayo]

I was reading a thread on another website about compressor explosions and this does happen with very dire results. This guy had the Lord on his side when his compressor blew right next to him. I will let you read the thread yourselves but he broke all the bones in his left hand and his tibia and femur of his left leg. There were three other people in the garage when it happened and thankfully they were all uninjured. If you have any doubts about the compressor don't use it until you get it tested and better yet just buy a new tank they are not that much money for the smaller ones.

http://weldingweb.com/attachment.php?attachmentid=60700&stc=1&d=1294099007

http://weldingweb.com/attachment.php?attachmentid=60701&stc=1&d=1294099030

http://weldingweb.com/attachment.php?attachmentid=60703&stc=1&d=1294099123

Here is the thread if you want to read the whole story.
http://weldingweb.com/showthread.php?t=48232

[Keith Outten]

Mike,

The compressor that blew up here in my area blew all four walls of a two car garage out and the roof came straight down. The guy who owns the garage was called to lunch ten minutes before the tank ruptured so the garage was empty.

After the explosion hit the local papers our Contract Administrator at NASA Langley had us inspect every single compressor in the system. It took me a couple of years to get every compressor inspected, some of the small compressors that were assigned to airplane hangers were mobile and it was a job to track them down. We removed the paint on every welded seam and MT inspected the welds. We also performed a UT thickness inspection on the tanks to verify the wall thickness. We condemned about 15 of the small compressors by drilling holes in the tanks. The large compressor tanks were repaired or the tanks replaced, they are not usually mounted on the tanks. Note that you have to be ASME certified to weld on a pressure vessel legally.

BEWARE...the majority of the time it is not rusted tanks with thin wall thickness problems that cause them to explode like the one above. Compressors mounted on tanks provide a constant vibration when they are running so the attachment welds, where the compressor mount is welded to the tank, are the area that is most susceptible to bursting/exploding. If you want to be as safe as possible remove the compressor from the tank and mount it elsewhere.
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[Bruce Wrenn]

I have one of that model of compressor. The cut out pressure is about 120#. Poster plainly states it was over pressured (150#.) To check a tank, you do a hydrostatic test. You fill tank completely with water or another fluid, then pressurize it to desired test pressure.

[Ray Newman]

Myself, I would junk the tank and Craig's list/Ebay the motor and pump.

Safer to buy a whole new unit. The old cast iron/oil bath pumps are still available, just not as common as they once were.

[Michael Weber]

Holy Cow. :eek: I also have a more than 30 year old Craftsman compressor that the pressure switch went out on just last month. I bought a replacement online and put it on. Looks nothing like original so it's now kind of a Fraken Compressor. After reading the above I believe I'll replace the compressor.

[Don Morris]

That's my compressor in the photo! Sure looks like it!!! LOML and I looked at the photo and then looked at each other. Guess what we're going to do? Yep, safety first. NEW. The original thread from that photo recommended putting the compressor separate from the tank. Hmmmm. Have to think about that. My small cut off tool is the only air drive tool I don't want to give up that needs a fair amount of air. It specs a requirement of 11.5 SCFM at 90 psi. My "recently departed" compressor specs 7.5 SCFM at 90 psi but worked well enough for me. So I guess I'm probably going to need something close to what I had: around 20 gallons, 2 HP, but I'm seeing a lot that are 120v in that range, not 220v, and not oiled as mine was. Any comments about 120v vs. 220v or oiled vs non oiled? Also, I go by the vertical tanks in Sears and like the space saving idea. So a vertical single tank next time. Comments please.

[Keith Outten]

Bruce,

Hydro testing is a safe way to test a vessel however you have to cap all of the connections to the tank except one so you can apply the appropriate pressure. Since very few people own a hydro pump most will fill a tank with water and then bring the pressure up with air from another source which is not as safe but its better than not performing the test. A rupture will not be earth shattering when the tank is full of water since water will not compress. You would normally test at one and a half times the working pressure of the tank but to be safe you should contact the manufacturer for instructions.

In the United States all air compressors are required to have an ASME stamp attached to the tank. This is your assurance that the tank was built to some very stringent specifications.
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[Michael W. Clark]

Oil-less is much louder. The oiled recip type are loud enough. Not to scare you, sounds like you already decided. Sometimes sitting idle is worse on the tank from a corrosion standpoint. I read this last night and went to check my 1971 Curtis. The tank is ASME U stamped for 200 psig at 400F. I have the pressure switch set for on at 90 and off at 110 psi, lots of safety factor. Only twice have I drained the water it looked rusty, the rest of the time it was clear. Both times after it had run then sat for a period of time (the first time when I got it, then recently when I hadn't been in the shop for a while after running it hard the last time I was in there).

I think I will move it up in priority on the "upgrade list".

Mike

[Jerome Stanek]

Those pictures look more like over pressure than rusted out The safety valve may have been removed or not set right. we have had rusted tanks and they all start to leak.

[Ronald Blue]

I have often wondered why air compressor tanks don't have the drill point "holes" like air tanks on locomotives. That way if rust out is an issue it begins to leak long before the tank integrity fails. Usually air tanks do just begin to leak when they are bad. As info it doesn't require that much pressure to be lethal. About 10 years ago a young man was killed here when a well pump pressure tank burst he was helping work on. It was in the 40-50 psi range. Things we generally consider as risk free sometimes are a sleeping bomb. It sounds like all that is needed to fix this compressor is a new pressure control switch.

[Jim Andrew]

I can't imagine that a guy needs a huge air compressor in a wood shop. I have the smallest one I could buy with a oil type compressor. Didn't cost a lot, and has lasted several years. Although not 30 like that one. Our local service station had an antique tank and compressor, the guy who owned the station replaced it with new, and said it cut his electric bill significantly. Wished he had replaced it years before!

[Matt Meiser]

If you want to spray finishes, run an impact wrench, or run an air sander decent size to big compressor is a must.

[Bruce Wrenn]

Remember out of the MILLIONS of compressors and tanks out there, HOW MANY HAVE FAILED? This was basically a freak, one of a kind, accident. Over the years, I've seen a lot of leakers, but no explosions.

[Michael Mayo]

Remember out of the MILLIONS of compressors and tanks out there, HOW MANY HAVE FAILED? This was basically a freak, one of a kind, accident. Over the years, I've seen a lot of leakers, but no explosions.

That is very true but I did want to share that catastrophic failures do happen with devastating results if they are neglected.

[Jerome Stanek]

People drive cars every day that are more dangerous than the air compressor. Also getting struck by lighting so maybe stay indoors.

[Steve Rozmiarek]

Remember out of the MILLIONS of compressors and tanks out there, HOW MANY HAVE FAILED? This was basically a freak, one of a kind, accident. Over the years, I've seen a lot of leakers, but no explosions.

I have personally seen the aftermath and my dad on crutches while his leg mended from a little one blowing up. In this case the guy he worked for was a cheapskate and bought a crappy old probably never maintained compressor at an auction. I know we all take better care of our tools, but some don't. Did your used compressor come from one of them? I won't buy a used compressor. A local service station also has a patched hole in the roof that serves as a reminder. That's too many instances to be freak accidents for me. That is one heck of a lot of energy stored inside that tank, it warrants respect.

[Thomas Hotchkin]

FYI after reading this thread, I got to thinking about my own 30 year old 20 gal air compressor. With a few call to local equipment rentals I was able to find a Ridgid manual pressure test pump for under $35.00 for half a day rental. I removed both inlet and outlet tank fittings, and filled air tank with water. Plugged outlet fitting and test line went into inlet tank fitting. With air compressor tank completely full water, you flush test pump buy pumping water through pump to remove all air from pressure test line, and then connecting to air compressor tank. My air tank is labeled for 150 max pressure I was setting for a test pressure of 225 psi 1&1/2 times max tank pressure. About 2 minutes later pressure gauge on test equipment read 225 psi. I let test pressure set for ten minutes, no drop in test pressure and on leaks from tank. And I was back using my compressor that after noon, spraying my latest project. Tom
http://imageserver.grainger.com/is/image/Grainger/1XDZ3_AS01?$productdetail$