Air Compressor tanks: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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March 31, 2011 11:24 a.m. jimbbski Reader

Last night I heard my air compressor start to run out in the garage. I must have left it on the last time I used it which was last week. I went in and turned it off and found a puddle of liquid running from it. I at first though it was oil from the cylinder crankcase but after I turned off the compressor I heard an air leak. It turns out that the tank itself has finally rusted out!

Now the rest of the compressor is in great shape. It's a 5 HP 220V 20 gallon Sears unit. It puts out over 9 cfm at 90 psi which most compressors with 20 gallon tanks can't. You have to move up to the larger 60 gal. compressors to get that cfm. I want to just replace the tank. Due to it's age Sears no longer sells a direct replacement tank. I have found a company that makes air tanks that will work but I thought that I would ask for any info or advise here that you may offer before I do anything.
March 31, 2011 11:54 a.m. motomoron HalfDork

Most of the replacement air tanks available are for high-priced US made industrial applications, see Grainger, McMaster-Carr, etc.

I'd troll Craigslist for a nice oilless compressor on which the pump has sh!t the bed. Certainly no more than $40. Make it work.

Under no circumstances weld your tank. In the past confronted with this very problem I'd considered acid-etching the inside of the tank and sloshing epoxy inside which would theoretically fix the leak without increasing the risk of a catastrophic failure, but seeing images of the damage resulting from a failed pressure vessel put me right off that.

Eventually I found a great, hulking 220V - 60 gallon - 5HP - 4 cylinder - US made Speedaire unit that's my last compressor. I've fitted it with a drain timer so it's bone dry in the tank year 'round.
March 31, 2011 12:51 p.m. dculberson Reader

motomoron wrote:

Eventually I found a great, hulking 220V - 60 gallon - 5HP - 4 cylinder - US made Speedaire unit that's my last compressor. I've fitted it with a drain timer so it's bone dry in the tank year 'round.

Hey, what do you do with the water coming from your drain? I'm getting tired of having to either clean up the water or leave rust stains on the floor. Did you run yours to a sewer drain or outside or..? I'll probably end up running mine outside, I just thought I'd see if you had any input.

I don't have a drain timer, but did put in a nice ball valve that's easily accessible. I can blow it out in no time versus reaching up under the thing. A drain timer is a great idea; we have one on the HVAC compressor at work.
March 31, 2011 4:45 p.m. 44Dwarf Dork

Most tanks today or not industrial duty not certified vessels. My 80 Gal upright tank came out of a dentist office it was made in 1954 so says the cert tag. still holds 140PSI just fine.

As for the drain i have 3/4 inch ball valve and plumbed a drain line to the outside...some day i plan on plumbing it over to where the neighbors cat likes to lie on my driveway....dam thing like to walk on my cars too.
March 31, 2011 4:54 p.m. mad_machine SuperDork

I need a new pump on mine. It tops out at 80psi and keeps running
March 31, 2011 7:32 p.m. fasted58 Reader

Electronic timed drain valves can be had for less than $100 at ebay stores.120V, 1/4" NPT w/ cord or hard wire. Ingersol Rand valves list out around $200. I like to use steel hydraulic fittings over schedule 40 pipe nipples and black iron fittings exiting the tank but I'm talking a big compressor.

Don't try to repair the tank. Even a welder certified in pressure vessels probably wouldn't attempt it. An amateur welder will just make the situation worse. If you're scrapping it, torch cut a hole in it so it's useless. Some fool might pick it up and try to fix it and ending up hurting himself or others. Or, cut it in half, make a parts washer or planter for the wifey.

I seen too many disasters waiting to happen, rather be safe than sorry.
April 1, 2011 10:37 a.m. jimbbski Reader

I don't plan on repairing only replacing! I have checked on some used compressors on Craigslist. I have also looked at new tanks. The prices are resonable at around $250 +tax and local pickup but I found one used compressor (Sears) for $250 but it was sold before I could contact the seller. I think if I keep looking at used ones for sale I can replace the tank with a newer one. I want a 20-30 gal. horz. tank. The vert. tanks don't fit where I keep my compressor or I would just get one of those.
April 1, 2011 1:46 p.m. jeffmx5 Reader

Speaking of compressors - a lot of us part-timers have compressors in the garage. I don't leave mine plugged in so I have to wait for it to fill whenever I need it.

My BIL had a small compressor in his computer store that he left plugged in all the time. He got a call one night that there was a (thankfully small) fire at his store, started by the compressor motor.

Just a heads up - I'd hate to hear of anyone loosing a house because of their compressor.