as i understand it the guys who do the good jobs use sacrificial period correct pieces of metal not modern wire, although i did here a rumour one guy had found some period correct wires.
for good pictures and threads on the work that is being done (at least what is being made public) Tz-uk has several threads on the work of rocco at watchworks in the uk ....the job of a laser welding repair ties very closely into the ability to polish afterwards and the skill level you have with that ...rocco was lucky enough to get possession of one of the bexley lapping machines when they moved and receive training on it and can polsih beautifully by all accounts ( i dont know him but i know a couple of people who swear by him)
http://forum.tz-uk.com/showthread.ph...pics-on-page-3
if you can be bothered have a look over there on this thread and search several other under rocco, laser welding etc and you will see what is being put out at that single establishment in uk who have been getting going with it for 12mths .....then wonder how good is the stuff from the guys in Italy and HK who have been honing their skills at it for years, improving continually both with practice and technology ....