how to repair rust holes in air compressor?

Bob Standal · Post by **Bob Standal** » Thu Jul 08, 2004 11:40 pm

I have a small compressor with a 10 or so gallon tank. it a few small (nail head size) rust holes in the bottom of the tank...any way to repair, or how can I remedy the situation? the compressor motor works great, I'd rather not just chuck it.... thanks!

JC-ATL · Post by **JC-ATL** » Fri Jul 09, 2004 5:23 am

I'm sure you could weld it up, but I wouldn't - wouldn't you hate to have a weld blow out at pressure? Most of the major manufacturers offer replacement tanks pretty reasonably.

bhowden · Post by **bhowden** » Fri Jul 09, 2004 8:15 am

Bob Standal wrote:I have a small compressor with a 10 or so gallon tank. it a few small (nail head size) rust holes in the bottom of the tank...any way to repair, or how can I remedy the situation? the compressor motor works great, I'd rather not just chuck it.... thanks!

I wouldn't try. An air tank full of compressed air is really just a bomb in disguise. If you can't get a new tank for that specific compressor, how about one of those portable air tanks? They are pretty cheap and already pressure certified. Worst case, leave the existing tank in place to hold the compressor and motor but by pass it and plumb the air to the portable tank as an external setup.

Brian

Travis S · Post by **Travis S** » Fri Jul 09, 2004 5:01 pm

I have never worked with an air compressor before, but can't you drain it somehow so there is no internal pressure and then weld it

JC-ATL · Post by **JC-ATL** » Fri Jul 09, 2004 6:36 pm

Yes, you can drain it so there's no internal pressure, but that's not really the issue. More to the point is that there's a chance your weld might fail under pressure when you use the tank, or that maybe you didn't get all the rust, or what have you.

R2.0 · Post by **R2.0** » Fri Jul 09, 2004 6:54 pm

Is there an ID plate attached to the tank, and does it have a little cloverleaf with a letter inside it? If so, you have an ASME code tank, and unless you possess an ASME R(epair) stamp, it is illegal for you to repair it, besides being just a bad idea. If it isn't an ASME code tank, it's replacement would be cheap enough so that the repair isn't worth it.

sideshow · Post by **sideshow** » Sat Jul 10, 2004 11:12 am

A friend of mine has a 1hp/3gallon/110v (err something really close) in his garage at home. Work threw it out due to a pin hole rust/leak out the bottom of the tank.

It gets regular use as a tire filler (top off cars, kids bikes) with some auto cleaning, so a light duty life. Not left on.

His solution was a hose clamp and a piece of mastic or rubber.

Bobby74 · Post by **Bobby74** » Sat Jul 10, 2004 4:53 pm

R2.0 wrote:Is there an ID plate attached to the tank, and does it have a little cloverleaf with a letter inside it? If so, you have an ASME code tank, and unless you possess an ASME R(epair) stamp, it is illegal for you to repair it, besides being just a bad idea. If it isn't an ASME code tank, it's replacement would be cheap enough so that the repair isn't worth it.

Illegal!! heh... Yes, you can weld up a tank. Its better to braze it though. At least thats what my dad has been doing (he's a Journeyman pipefitter). A good MIG welder can do the job as long as you don't anneal the metal. Dont heat it for too long. We've converted old Freon tanks and Propane tanks to air compressor tanks. I wouldn't use it over 125psi though. Make sure you have a decent cut off valve. They are only about $15 from a compressor store like Portland Compressor. It most likely pinholed due to rust, but it could've been a bad seam or just a thin spot in the tank.

Take care,
-Bobby

BugMe · Post by **BugMe** » Sun Jul 11, 2004 6:32 pm

Ever see the original JAWS movie? What was that Roy Schieder used to blow up the shark? Ah yes, it was tanks full of compressed air. Sure, they were scuba tanks, but I'm sure you can get the picture. For the sake of a few hundred bucks, I'd rather replace the compressor or tank and be able to say good night to my kids.

bugninva · Post by **bugninva** » Sun Jul 11, 2004 6:45 pm

Bobby74 wrote:[
Illegal!! heh... Yes, you can weld up a tank. Its better to braze it though. At least thats what my dad has been doing (he's a Journeyman pipefitter).
Take care,
-Bobby

sure you can weld it...but as R2.0 pointed out if it is ASME certified tank it is illegal to weld on it without proper qualifications(r stamp) and also you must file documentation on the repair....Not likely that the aircompressor has an ASME certified tank, but that doesn't make welding it any less dangerous to anyone near the tank...this coming from a former pipewelder with pressure vessel certification(boilers)..

Guest · Post by **Guest** » Mon Jul 12, 2004 3:36 pm

Yes you can weld it, BUT unless it was a certified welder from a tank manufactorer I would'nt trust it.
It's only a 10 gal tank, just do what Bhowden said, get one of those portable 10 gal air tanks and hook your compressor to it. You guys act like this is a proffessional series 2 stage 100 gal compressor that cost $2000+, it's just a portable comp that can be replaced for around $100.
Here's a link to an air tank on Harbor Freight
http://www.harborfreight.com/cpi/ctaf/D ... mber=40057
This one is $30 and I've seen them cheaper.
John AKA Coils

R2.0 · Post by **R2.0** » Tue Jul 13, 2004 8:10 pm

Bobby74 wrote: Illegal!! heh... Yes, you can weld up a tank. Its better to braze it though. At least thats what my dad has been doing (he's a Journeyman pipefitter). A good MIG welder can do the job as long as you don't anneal the metal. Dont heat it for too long. We've converted old Freon tanks and Propane tanks to air compressor tanks. I wouldn't use it over 125psi though. Make sure you have a decent cut off valve. They are only about $15 from a compressor store like Portland Compressor. It most likely pinholed due to rust, but it could've been a bad seam or just a thin spot in the tank.

Take care,
-Bobby

Well, it's not like the compressor police are going to show up. OTOH, if a repair or conversion does let go and someone other than the owner gets hurt, it's the owner that gets their ass sued/arrested (negligence).

One trick is to throw a hydrotest on the tank. I think ASME Section XIII calls for 1.5 x Max Design Pressure. Fill the tank with hydraulic oil, and hook up a porta-power. Crank it up to 125x1.5=187.5 psi and hold for 10 minutes. If it's gonna let go, it will then, and it is a million percent safer than air testing.

No porta power? Old beetle master cylinder (single circuit) in a fixture would be really low rent, but would get the pressure you want.

gerico · Post by **gerico** » Sat Jul 17, 2004 9:39 am

DON'T use a freon tank!

Bob Standal · Post by **Bob Standal** » Sat Jul 17, 2004 11:46 am

thanks everyone for the replies! due to its small size I don't think i really even need it. It is a 1/4hp 10gallon (or so) compressor that runs off 110. I have another that is larger (2hp?) with a slightly larger tank that runs off 220 power. I will sell both at milan show next weekend for 75$. both have running motors. Any takers? Offers?

Paul Illick · Post by **Paul Illick** » Wed Jul 28, 2004 10:28 am

DON'T weld it. If it's got rust holes what's the rest of the metal like? So what are you going to be welding TO? How much good can you do welding a good patch onto rusted through metal? Why on earth would you want a bomb around? That's the kind of thing that takes off a hand or a foot, usually some innocent kid's. Get rid of it.

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how to repair rust holes in air compressor?

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