Bass clarinet comes in from a school with a broken Left Hand Low F#/C# Lever. This type of break requires that the key be silver-soldered (or brazed). The key is held in a jig and heated red hot, then silver solder is used to connect the broken pieces back together. If done properly, the break should be as strong, if not stronger, than the original key.
Left Pic – Broken F#/C# Lever
Right Pic – In the jig ready to be soldered
Left Pic – After soldering, but before cleanup and polishing
Right Pic – Back on the horn, polished and ready to go