I have a 1974 Honda Xl125 exhaust pipe which has a crack in it. I attempted to weld the crack, creating a hole accidentally.

How should I properly patch the hole?

Here is a link to a photo for reference, including a 10mm socket for size reference:

enter image description here

2 Answers 2


Personally I would make a collar ie a piece of tube with a slit and slide it over the damage, then probably braze around the top, bottom and the join...

I would braze as the parent metal seems thin with lots of surface corrosion "dimples", so the collar should add some strength. If your welding is really good then you can weld it - but given the hole you created....

  • Wouldn't a steal epoxy like jb weld get the job done? I believe it is heat resistant. Jan 27, 2019 at 11:30
  • Define "heat resistant" : will it survive contact with hot exhaust gas? Try it and let me know. According to the product spec it is good up to 550F ie 290 Deg C - exhaust gas temperatures are above 1200F so ...
    – Solar Mike
    Jan 27, 2019 at 11:35
  • Dirt bikers commonly use them to fix engine chase cracks on the field and it supposedly holds up. Jan 27, 2019 at 11:38
  • 1
    There is a BIG difference in the temperatures of an engine case and the exhaust pipe shown by the OP in the image supplied... As I said you need to check the temperatures...
    – Solar Mike
    Jan 27, 2019 at 11:40

I wound up welding this back together with flux core.

The mistake I made was running a bead for too long, heating the base metal past its melting point.

The solution I found was to bit by bit deposit welding material around the parameter in short bursts allowing the base metal to cool between passes, After the hole was filled I ground it down with a dremel.


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