Brazing

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KDXrider1989
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Brazing

Post by KDXrider1989 »

The end of my FMF muffler has been screwed up since I bought it used and have tried JB weld to close up a crack at the end only to see it leak again in about 5 rides. I had plans on sawing off the old, beaten-up end of the canister and braze on a new end out of 3-inch flat aluminum, I would like to have it welded but that is ridiculously expensive. Do y'all know if brazing is a good idea, and if it can stand the vibration, oil, and heat of the exhaust?
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SS109
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Brazing

Post by SS109 »

Try brazing the crack closed? I bet that would work better than making a whole new end. Anyways, brazing will handle the oil and heat at the tip no problem. Vibration could be another issue but I would bet it will hold fine if the brazing is done right.
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Brazing

Post by the machinist »

If you pay the shipping I will weld it for you, free. I now have way to much free time, see *graphic picture* post. Brazing might work but welding is better.
KDXrider1989
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Brazing

Post by KDXrider1989 »

SS109 wrote:Try brazing the crack closed? I bet that would work better than making a whole new end. Anyways, brazing will handle the oil and heat at the tip no problem. Vibration could be another issue but I would bet it will hold fine if the brazing is done right.
I was going to replace the whole end for cosmetic purposes, it's all dented and ugly-looking. But if in fact brazing cannot hold well against vibration, then I guess I'd have to just close the crack and see what happens
KDXrider1989
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Brazing

Post by KDXrider1989 »

the machinist wrote:If you pay the shipping I will weld it for you, free. I now have way to much free time, see *graphic picture* post. Brazing might work but welding is better.
Wow, thanks! But this is something I'd like to get done in one day because I might go for a ride this weekend
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Slick_Nick
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Brazing

Post by Slick_Nick »

KDXrider1989 wrote:
the machinist wrote:If you pay the shipping I will weld it for you, free. I now have way to much free time, see *graphic picture* post. Brazing might work but welding is better.
Wow, thanks! But this is something I'd like to get done in one day because I might go for a ride this weekend
Then brazing is the way to go.
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Re: Brazing

Post by KDXrider1989 »

got some rods today and tried to seal the crack. no deal. this stuff is kinda hard to work with
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Slick_Nick
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Post by Slick_Nick »

Probably you heated the rod and melted it which is incorrect. Heat the exhaust cap, then touch the rod to it (without direct flame) and it will flow in nicely. If you just heat the rod, it will sit "on top" of the cap and not adhere. Wire brush and use a good flux if need be.
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Slick_Nick
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Brazing

Post by Slick_Nick »

This guy does it great and shows the WRONG way to do it too.

[youtube][/youtube]
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Re: Brazing

Post by KDXrider1989 »

I did heat the rod directly, and the aluminum did pretty much sit on top and not bond. I have flux-core rods, the guy in this video looks like he's using more of a solder. I'm going to go try this right now and see what I get
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Post by Slick_Nick »

I use pure aluminum rods, and a paste flux when I need it. You MUST heat the base metal and not the rod.
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