I had looked into this after I bought a Speedmaster Professional case that had a few pretty substantial dings. My local watchmaker was able to refinish the case without laser welding, but I had come across this information about the process as it relates to watches.

Under the Loupe/Case restoring

: Fantastic restoration . . . every molecule of the watch looks
: just the way it should!!

: One question, please: Can you explain what is happening with the
: rust, the new material and the laser? Are you actually
: "drilling and filling", as a dentist might proceed?

: Can you please tell us what is happening in the two photos that I
: show below?

: Huge thanks and all good wishes that you will enjoy this watch,
: "in the best of health", as they say.

: Jeff