compressor tank repair

It may be a crack in steel. I had a compressor tank that had such a crack. You need to examine it closely.

Since those tanks normally have a big 2" port on the side, you can remove the fittings from there and inspect inside with an inspection mirror and a flashlight.

Definitely recommend carefully removing the paint from a good area around the leak for a close inspection for cracks or other issues.

If you can, try tapping to something like 1/8" NPT and put in a tapered plug with some Rectorseal and skip any heating process like welding/brazing/soldering.

Important things to keep in mind:

- Inspect carefully for cracks

- Avoid any heating process that could change the metal strength

- The force on small holes / plugs is small, so you don't need welded or brazed connections. Even a 1/2" dia plug at 120 PSI is only about 25# force.

- Pressure tanks are not magic, so if you inspect it and find it is just a manufacturing flaw in the weld, and you repair it without doing anything to compromise tank strength it should be fine.

Well, it's right on a weld where the bottom bung is attached. I wish i still had that tank I sold you :)

I have a friend who is an ace welder with aircraft certs. I may run it by his place and see what he thinks

The tank you sold me, was used to replace the tank with the above mentioned crack. ;-)

It should be easy.

Use jb quik, for those times when you're in a hurry and can't fix it right. Remember to criss cross some duct tape over it too, eih?

There are several products for preserving the interiors of car doors etc that might stop other weld defects from rusting through, or plug them.

jsw

Everyone agrees on that, but how? If it was the hull of a sub or a reactor vessel they would use xrays. There must be a good reason for that, so something more than a magnifying glass might be advisable. Maybe some chemical would make a crack more visible under a UV light?

Good 'ol Magna-flux would work, but I think just cleaning the paint in the area and inspecting with a magnifying glass and good lighting would do. Combined with a visual inspection inside the tank via the 2" side port that should give reasonable confidence that it really is just one porous spot in the weld.

Compressed air and soap, just like a tire.

jsw

Tom Del Rosso wrote in rec.crafts.metalworking on Sat, 4 Dec 2010 14:33:03 -0500:

Clean off all the paint and stuff, then apply a little solvent. Wipe dry with a paper towel or clean cloth. A crack can show up when the solvent in the crack wicks out to the dry surface.

I'd clean with a wire brush and weld it. It was welded to begin with.

Bob

Yes there is; go to a welding supply place - they've got some kind of penetrant that you smear on, let it dry, and use another chemical to "develop" it, and the cracks show up red.

Look for Dynaflux PWW Penetrant; according to this can here, you also need their cleaner and developer, but the guy at the welding supply place should be able to fix you right up.

And you don't even need UV. :-)

You might have to remove all the paint, but that should be fun too - I heard about a guy who washed his lawnmower with Tide, and the paint all just fell off. ;-)

Good Luck! Rich

Kerosine works well. Possibly it wasn't a crack, but slag in the overlap at the end of the weld.

jsw

shhhh..... it's supposed to be a secret...... ;>))

"Stormin Mormon" <

Yep----the nice, shiny silver colored stuff---not the red or black type.

You know---the "handymans's secret weapon". :-)

thanks for all the good input.

Despite the duct tape jokes, I think I'm going to try JB weld first. No sense adding heat if I don't need to. I intend to remove that big plug in the bottom first. that will let me inspect the area with an inspection mirror. If it looks clean I'll rough it up and use some JB putty on the inside. Then invert the tank and apply JB Weld on the outside.

I suspect that should work fine for a long time. If not, I'll take it to my welder friend.

removing the plug is a big "if". It's about 2.5" across the flats, maybe bigger. The flats are narrow, so it would be hard to grip with a wrench or pipe wrench. I do not have a socket that big. If i can't get it off, welding/brazing may move to the top.

This is exactly the reason I hate jbweld so much. Guys like you smear it all over the place pushing it into tight spots that are hard to clean out and then when it fails, as it will, you bring it to a weldor to repair. That stuff produces the most obnoxious toxic fumes you'll ever come across! You're only going to piss off the welder you bring it to. Don't use jb, weld it now and be done with it!!!!!! I'll say the same thing for brakeclean in the spray can. If you can smell the fumes when you are welding, STOP! Clear the air and get rid of the fumes. I've been in shops where it was being used twenty feet away and it was still a problem. The UV rays from the weld arc have an affect on the fumes producing a poisonous gas that you don't want to be around. Think, be careful out there, eih? phil k.

If the leak is in fact weld porosity, wicking grade Loctite 290 is a more appropriate noxious goo. See p.12 of this doc:

That reminds me of when I had a shop near the fish wharves in Bass Harbor ME. I'd cringe whenever the bait hauler from the Swan's Island lobster co-op would walk in looking to have some welding done on his aluminum bodied bait truck. Burning fish gurry is not as dangerous phosgene, but it undoubtedly smells worse.