Originally Posted by XR650L_Dave
Yeah, I wouldn't repair anything too critical that way, worked when I needed it to though.
I thought what set brazing apart was the filler would (very slightly) alloy with the base metal?
Brazed joints can be very strong if they're done correctly. A tight joint, properly cleaned and fluxed, will suck silver solder in by capillary action. Motorcycle and bicycle frames were assembled this way, and the parent metal would fail before the brazed joint. Another type of brazing known as bronze welding, using a nickel-bronze alloy, was and is used to assemble motorcycle and race car tubular frames. The alloys used have the property of forming large fillets, and that accounts for their strength.
Braze does combine with the base metal at the join point. It's been classed as hard soldering to set it apart from soft soldering involving lead-tin alloys. Flux has to be used for both types.