jB weld for an exhast leak?

[blckwlfny1]

In my attempt to smooth out airflow, it seems I ground off too much weld from the inside of my exhaust. Now it leaks from the joint between the pipe and the flange that attaches to the exhaust port. I was going to patch the hole (a 1/2" hairline) with JB Weld from the inside. Has anyone tried that? Will it work permanently? Or will I constantly have to re-patch it?
Thanks

 

[professor]

JB has heat limits. Try gold color hi temp silicone. I have been using it for turbocharger gaskets.

 

[old guy]

Give it a try. I'd probably patch from the outside since there might be a little temperature difference. I remember reading that JB weld is good for about 350-400 degrees so you might be okay.

 

[kerf]

You WILL burn JB Weld or silicone. Take your muffler to a welder with a MIG or a TIG and have him spot weld the leak. Regrind the area, being more careful.

 

[Turtle Tedd]

Having it TIG welded with silicone bronze (everdure) filler wire might be your best bet..

 

[motorpsycho]

yep, jb weld will melt away from the heat. it's just a plastic based epoxy, and it will melt. don't beleive the "weld" that's in the name or the "steel" on one of the tubes.
they use the word "steel" in referance to how strong they think it is, and not what is in it (as in "strong as steel".)
there is no steel in jb weld.
your best bet is to just have it welded or brazed.

 

[Turtle Tedd]

Yes JB Weld is just about worthless..they went a long way by putting the word weld in the name of that stuff....should have named it JB Bondo...works real good for contaminating a joint that must be TIG welded soon after...works ok for filling up the hole if one of your teeth has a bad cavity.

 

[adb140275]

You won't melt high temp silicone, exhaust on small 2 strokes wouldnt reach 800 degrees

 

[kerf]

You won't melt high temp silicone, exhaust on small 2 strokes wouldnt reach 800 degrees

Yes it will, silicone will not hold up well on exhaust, especially in the header. At least from my experience, I've cooked about three feet of silicone exhaust hose and it doesn't last very long. Steel tubing & flanges all nicely MIG welded work just fine.

 

[blckwlfny1]

Ill go to a welder and do it right. But I disagree on the silicone. The pure stuff from the tube is regularly used in the (litigious) Northeast US by professionals to hold fireplace flues together. Holding a blowtorch to it well only get it to glow. It will not melt or malform.