[Lippy]

Hi, I have a crack in the joint of the exhaust on my '48 Indian Chief. The exhaust is chromed. It is on an edge and the metal is fairly thin, so I'm wondering if I can (1) TIG braze it (silicon bronze) over the chrome, (2) carefully grind off a small amount of the chrome and braze it, or (3) grind it and TIG weld it, which would likely require replating the whole piece. What is attractive to me about brazing is that it is done at a lower heat, so I'm less likely to burn the edge, and it would look good enough as well. Being an old twin, it shakes a lot, but I've largely fixed the shaking problem on the exhaust and think the brazing should be strong enough. Of course, if I screw it up, I can still get a new part and it isn't the end of the world, but it would be good to fix it. Thanks for any guidance on what will work, and exactly how to do it.

IMG_2894.jpeg (3.5 MiB) Viewed 1625 times

[cj737]

You can braze it if you clean the chrome off, and do a reasonable job cleaning the interior. The only benefit of the SilBr is that it would be more ductile than ER70-.

[BillE.Dee]

I'm kinda thinkin that crack goes all the way around the flange, just not visible ... YET. Maybe get some SiBz on the there (away from the last visible area), after cleaning and then chase the rest of the fit.

[Lippy]

Thanks. Not sure how I would really clean the inside. The crack is thin and I can't get that far in from the openings at the ends. How would you approach that? Maybe squirt some acetone in?

[BugHunter]

Thanks. Not sure how I would really clean the inside. The crack is thin and I can't get that far in from the openings at the ends. How would you approach that? Maybe squirt some acetone in?

If you can't reach in there with anything, it can't be cleaned. The soot isn't going to just rinse off. Short of having a giant ultrasonic cleaner, forget about that. Get what you can from the outside. You might need to run your torch over it lightly to burn out any flammable crap that's in there, (not 100% burnt gunk), then re-clean the surface and continue.

I'd be curious to hear how you make out. Chrome being a carbide, it should stick to the SiBr 'ok'. Carbide inserts get brazed every day. But with the part being thin, it might get interesting. Stainless is a poor conductor of heat, but nothing like carbide.

[Lippy]

Thanks. Not sure how I would really clean the inside. The crack is thin and I can't get that far in from the openings at the ends. How would you approach that? Maybe squirt some acetone in?

Stainless is a poor conductor of heat, but nothing like carbide.

I thought I'd clean and grind away the inside of one of the ends, so it isn't visible but I can get a ground on it.

Separately, would another option would be to use 309 filler rod, as I hear it is forgiving and for dissimilar metals (e.g., stainless, which has chrome <> carbon steel)?

[BugHunter]

As far as it's already broken, I might be inclined to just break it the rest of the way and clean it properly inside before starting. Might be easier.

[cj737]

I doubt those pipes are stainless, likely carbon steel and chromed. You could confirm that possibly with a magnet.

Grind away the chrome, braze it up, buff it clean and shiny. And, do check the entire circumference for further cracking. You can drill the end of the cracks to prevent them from continuing and weld it all up. Bobs your Uncle-