How to Repair an Air Compressor Tank

My 28 gallon air compressor recently sprung a leak and I was determined to fix it.  The tank is only 5 years old and it is not that rusted yet.

I don’t recommend that anyone try repairing their own tank.  A weakened or improperly repaired tank has the potential to rupture violently with enough explosive force to seriously injure or kill.

The air was exiting at a weld joint for the compressor mount.  My guess is the original weld may have partially blown through the case.  I run my compressor hard and since the belt wasn’t perfectly aligned, this caused excess vibration and stress at the weld joint.

My trusty angle grinder to the rescue.  I needed to get a better look at the extent of the air leak.

I had to cut the mount plate away and grind the weld spot smooth.  The hairline crack was so small… I couldn’t see it.  I had to partially pressurize the tank to locate the crack.

I have a mig welder, but I’m a novice with it and didn’t want to make matters worse.  I’ve had great success with brazing in the past and thought brazing was an excellent solution for this problem.

I am using bernzomatic bronze brazing rods which have a tensile strength of 60000 PSI and a working temperature of 1620F.

I use a mini torch setup with mapp gas and oxygen, which can produce a temperature around 2400F.

Here is my mini torch with mapp gas only.  The flame appears slow, very orange, and with lots of black soot.

Here is what it looks like after I add the oxygen… a very hot focused blue flame.

Not pretty but very very solid.
I over shot the crack for added strength and stability.

The secret of brazing for me… is patience.  It took a while to heat the metal to the point it would melt the bronze.  My torch is smaller than most, but that’s my problem.

Here she is.  I carefully aligned the belt to reduce vibration.  I pressurized the tank to 125psi and the gauge reads the same after 24 hours.


  1. Thomas
    May 13th, 2010 at 15:04 | #1

    I like the mini torch you are using, what make and model is it?
    I couldn’t find anything like it at the Bernzomatic site.


  2. May 13th, 2010 at 15:28 | #2

    I bought my little torch several years ago. Here is the company and the latest versions of their mini torches.

  3. February 8th, 2011 at 02:14 | #3

    You did a great job with your air compressor… Yes you are right repairing air compressor or maintaining it should be done by professionals because it carries risk etc and I must say you are a professional having done it your way. Great Job!

  4. June 20th, 2011 at 19:44 | #4

    Thanks for the help!!
    This worked! I had tried everything for mine nothing worked and then I tried waht you said and it worked!
    Thanks for the help!!

  5. January 3rd, 2012 at 23:35 | #5

    Thanks for your tips to repair Air Compressor Tank . This kind of post will be very beneficial for us . Many thanks for sharing it with us.

  6. January 4th, 2012 at 00:42 | #6

    Your welcome! It’s been at least 5 years now and I use my compressor often. The repair is still going strong! No doubt in my mind that brazing is the way to fix small leaks on an otherwise solid and sound tank.

  7. March 26th, 2012 at 05:07 | #7

    I like the post to describe the repair of air compressor tank. The way of describing via image use make it easier to understand. Thanks.

  8. troy nall
    June 29th, 2012 at 01:17 | #8

    its this type of “thinking”(or should I say “doing”) that my grandfather and his father before him, use to use daily to fix everything around the house/farm/etc… ive always fixed everything that I could(washers, dryers, fans, etc…) I really think thats whats wrong with our world. people don’t wanna put forth the effort to fix something that could be “fixed”. Now grant it, I use my fair share of JB weld and duct tape on things, so i will not throw stones, but there is something to be said about being able to fix your stuff and not going out and buying the newer best-ist shiny toy. and if anything, thats what I get from your videos and tutorials.

  9. September 25th, 2012 at 10:25 | #9

    I have had my air compressor for atleast 7 years now and it still works wonders. I have a MAKITA (Which I think is the best brand). If you guys are interested in a air compressor that will last very long I recommend you check out this site.
    Great post by the way. The images really helped

  10. Paul
    January 19th, 2013 at 00:31 | #10

    At my previous job a local welding shop welded a leg back on. It had a leak where the leg was attached. A few years later the compressor exploited. Two of us ended up in the hospital. The insurance company found that it exploited because of the welding causing metal fatigue. Don’t mess with them. It could kill someone and cost you millions.

  11. January 19th, 2013 at 00:40 | #11

    Thanks for the feedback Paul and I do not take your advice lightly. But I brazed my tank and the tank was almost new at the time. I would guess that was about 8 years ago and the tank is showing no sign of fatigue. A traditional weld would be more dangerous because it can blow through the metal and weaken the integrity of the tank.

  12. January 20th, 2013 at 20:20 | #12

    I want to reiterate the risks associated with fixing a tank that is meant to be under pressure. I sell compressors and have had many people ask me to come in and size a new unit for them. When I got to one shop I saw holes in a cinder block wall where the shrapnel from the exploded tank went through. The company was lucky that it went at night when nobody was there. If you have a problem with an air compressor tank, please take it to, or call, a professional for repair. The little bit of money spent could save yours or someone else’s life.

  13. Steven Jarris
    March 18th, 2013 at 13:36 | #13

    I think that the air compressor in Toronto is something that will help me improve my lifestyle every day. Thanks for sharing this information.

  14. October 4th, 2013 at 05:46 | #14

    You’ve provide such a great solution or idea to repair air compressor tank. I recently face such type of problem with my air compressor. I would definitely solve my problem by following your great ideas.

  15. March 18th, 2014 at 16:45 | #15

    That was the most comprehensive concept i ever encounter!
    great job!!!
    thank you!

  16. Joe
    September 27th, 2014 at 18:42 | #16

    2 words

    MIG welder.

  17. September 27th, 2014 at 18:48 | #17

    I don’t have a MIG welder and I personally think that a MIG welder in the hands of someone without the right skill… would actually make the problem worse. Perhaps in the right hands a MIG welder would work well.

  18. Tom Henry
    December 7th, 2014 at 21:43 | #18

    One question, was this a Chinese product?
    I have not read any of the other posts submitted in response to your compressor repair buy my guess is that this is a Chinese product and like any other tool or equipment made in China and sold through Harbor Freight, it lasts about 6 months and then breaks.

  19. Tom Henry
    December 7th, 2014 at 21:52 | #19

    One thing I want to point out is about “Temper”. I do not know if the metal of your compressor tank was tempered or not but if it was, any type of heating which would make the metal “red hot” alters the temper and therefore the strength of the metal. It the temper was altered ans the metal subjected to pressure, in this case, air pressure from the compressor, the metal may then fatigue and give. The result would be possibly an explosion. Exercise caution and diligence when welding or brazing any part which may be subjected to loading or pressure.
    Good work though on a problem that never should have happened if the compressor was properly engineered and built to begin with.

  20. December 7th, 2014 at 22:07 | #20

    @ Tom Henry. Thanks for the feedback Tom. The compressor is a Husky from Home Depot bought sometime around 2002. I repaired it in 2008 and I have been abusing it ever since. It has been used often and cycled heavily each fall to blow out my sprinkler system. She is still running fine and the repair is still solid. I think the original crack was caused by a bad weld for the compressor head and original belt alignment was poor which caused excessive vibration which in-turn caused metal fatigue at that weld point. Not sure what a good lifespan is for this type of compressor, but I will probably replace it well before that braze ever fails. This was the right repair for this particular problem. Harbor Freight makes some good stuff, but I won’t get one of their compressors. THANKS.

  21. March 17th, 2016 at 03:08 | #21

    Don’t really know anything about it, but couldn’t it be brazed?

  22. April 8th, 2016 at 00:49 | #22

    I have an old compressor and it has rusted through near the drain valve at the tank bottom where one would expect trouble. I am thinking the worst that could happen is it leaks again sometime down the road. I certainly would not want something that could blow & become a safety issue. Thanks

  23. April 8th, 2016 at 09:21 | #23

    Most likely, that is what would happen. However, a weakened and rusty tank is the type of tank that is more likely to have catastrophic failure. I was able to braze my tank because it was fairly new and I could be confident that the tank was sound.

  24. May 28th, 2016 at 02:32 | #24

    Hello, I have a similar craftsman compressor that I just rebuilt a year ago (new reeds, piston ring & cylinder)and its already dying…doesn’t produce above 110 psi. Had same problem getting to those torx, I ended up filing down a cheap flathead screwdriver to fit the torx and it worked great. Im not sure if this POS is even worth another ‘rebuild’ considering how long it lasted. Never heard of the graphite/silicone grease in the cylinder, I will definatley try that. Also good ideas about the dirty air

  25. April 25th, 2017 at 03:56 | #25

    Thanks for the helpful tips! I was already going to buy a new air compressor. But I see that this kind of problem can be solved.

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