High nickel castcraft rods and turn the amps up to 140 (max on these old things).
I read all the stuff on the net about heating and tried it all which was very fiddly.
Now I just clean the weld area up with a grinder, tack it then go. No post-heating.
Has worked just fine on a cracked old wood stove front, broken handle on a very old (valuable) automatic wine bottle cork puller, broken MF steering box case, etc.
Maybe just lucky.
DL

