I have used silver solder to attach lugs for pannier racks to bicycle frames. Bicycle frame tubes are high alloy steel and rather thin so brazing is used onty where the tubes meet cast lugs. Silver solder is much stronger than lead/tin solder and requires a higher temperature but much lower than brass/bronze. And the surfaces must be clean. Most of the brazing rod I've bought lately is actually bronze and requires a higher temperature than brass. Stronger though. Silver solder ain't cheap, though.
