I have welded numerous SIG P210s and a number of Lugers as well.
All my welding is done with a TIG and with the tig I have also welded very close to stamps, that close that the new weld is almost insiede the stamp.
I have welding wires that is very close to the original material , but even though it's very difficult to ALWAYS SUCESS.
As important as the welding rod is, is also the heattreatment and the hardness of the weld.
Normally the weld gets a little bit harder and to have the sligthest chance to make a good job the parts have to be preheated and most important of all anneled.
Best would probably be to softtemper the frame after welding and reharden the camsurfaces.
A furnace is a must.
The most problematic part of all is that you are never really sure that the colour of the weld is going to stay the same as the rest of the gun, the change can often come 2 years later.
Now is the welding and the heattreatment and the wire not the only problems, there is two more problems.
Those are the craftsman and the bluing.
Before I had my own salt bath i went to a profesionnal company, on one occasion I had welded away a dovetail at a 1911 comp.
THe bluing they made on it was perfect, but when they gave me the comp the man dropped it to the floor.
Really sadly as there was no traces of the weld at all.
I had to remove the marks on the comp after the floor repolished the part and got it blued again, and now was the weld there, very visialbe.
I belives the temperature and the time that the part is in the bath is very critical, best result is often at the higher temperatures and often to let the parts stay in the bath overnight.
Regards HÃ?Â¥kan
http://www.vapensmedjan.com