air compressor repair

Date 09-14-2010 04:07

A buddy on mine has an air compressor that has a badly rusted tank and he wants to patch the tank with a piece of stainless steel. Mate a piece of stainless steel up with a lap joint and tig weld it. this is the response I gave him I am just wondering if I missed anything or if anyone has any thoughts on the matter
Thanks Chris

i would buy a new tank but If you want to patch the tank use a butt joint, when you pressurize and depressurize the tank the metal expands and contracts and a lap joint has a sharp that edge at the root of the weld (where the metal lays over the other piece of metal) that might start a crack and cause your weld to fail.
Stainless is typically harder and may not stretch the same as the mild steel and cause stress in the weld zone, and I think SS is prone to work hardening
In all reality I think you will be fine but considering what can happen if it fails personally I am not sure it is worth the risk

By L51174

Date 09-14-2010 12:04

I agree with buying a new tank. Tanks are pressure tested and certified, and built with a safety factor. 150 pounds of air letting go could kill someone. I wouldnt take the risk.

By RonG

Date 09-14-2010 13:09

A patch would only work if applied inside and yes it can be done but not likely to be worth the trouble. A patch on the out side would have applied load on the welds only.

By A_DAB_will_do (*)

Date 09-14-2010 12:48

If the tank is badly rusted, then guaranteed there are other spots just waiting to fail. Patch the current hole, and I'll bet you'll have another failure somewhere else in no time. Not worth chasing all the problems. Buy a new tank.

By awspartb (***)

Date 09-14-2010 16:38 Edited 09-14-2010 16:58

Not worth the risk. No shops around here will even touch an air compressor for welding repairs. Ask the guy in the picture below:
http://i266.photobucket.com/albums/ii259/lincolnmorgan/aircomp.jpg

WARNING: VERY GRAPHIC PICTURE IN LINK, open at your own risk

Sorry, I took the tags out of it so that you have to click the link to view the picture-JW moderator

By Lawrence (*****)

Date 09-14-2010 17:03

Nuff said.

Replace it.

By awspartb (***)

Date 09-14-2010 22:00

I didn't mean to offend anyone by the photo. Sometimes a picture like this will save a life down the road. I was unlucky enough to have been on a job site that had a fatality caused by an explosion (not the one pictured). It will change your whole life when you see it in person. The guy who caused it was NOT hurt but he worked like a moron and refused to follow basic safety protocol. He liked to "burn 'er in hot and deep" if you know what I mean.......(chaw spit optional).

By 65 Pipeliner (**)

Date 09-15-2010 00:31

It's NOT worth it. Buy a new tank.

Chris

By Tommyjoking (****)

Date 09-15-2010 00:50

Replace the tank or scrap the whole affair out. There are very good reasons for all the codes on pressurized vessels....they kill people when it goes wrong.

By Lawrence (*****)

Date 09-15-2010 04:14

Not offended at all... Nuff said means your picture makes it perfectly clear that the dangers outweigh the fix.

By jwright650 (*****)

Date 09-15-2010 11:28

I wasn't offended either, just thought that it might be a bit shocking for a young reader browsing in the forum.