Fill flange crack?

boom boom

;)

Why wont braze work?

Oh you note on engineers err thats what i do. And a ticketed welding man.

I'm assuming these are alloy hubs?
In which case they're forged and machined aluminium. You can forget about doing anything to them.

What difference does that make?

You can weld ali no problem, it's just a bit harder to do than if it was steel.

You can weld alloy sheet and tubing and you can weld machined and forged shapes to other profiles, but the forging/billet turning process used to make hubs is specifically designed to keep the alloy structure correct to hold a spoke under tension. If you heat it up and add a welding rod into the mix you will alter the mechanical properties.

Embarrasingly, I've a degree in Materials science. Ha Ha. But hey, it was dual honours. And a long time ago. Somewhere in my basement are my lecture notes. Maybe I should go have a look and see if there are any on camagnolo manufacturing methods..

AlexB is right that heating up a bit of metal changes it's microstructural properties. Which may or may not be a problem depending on the specific manuafacturing methods and what the makers were trying to achieve with the microstructure.

Any alloy "product" (steel, alu, whatever) will have been formed in a through a complex combination of heat treatments and mechanical processes to achieve different results according to the application. So whether it's "ok" to weld is not a simple question to answer, whether it's alu or steel or whatever. But heck, I'm not trying to get Concorde to fly again..

I know, I'll cut the hub in half, polish the surface and photograph the microstructure using a microscope for you. I'm not busy this afternoon. And I'm sure everyone is utterly fascinated.

Or I might just go get a sarnie for lunch instead.

people on here are proper little bitchs, fucking repair and ride!!!!

material blah grain structure oh! pussaayyyyyys!!