I did extensive pit welding and cosmetic repair on a Win. 1892 receiver and bolt. My welder is a Miller MaxStar 151 inverter machine. Generally speaking, an inverter will sustain an arc at very low current (Miller says 1-amp on my machine)which is necessary for eliminating the crater when the arc is terminated. I use a thumbwheel current control on the torch handle. It makes it fairly easy to strike the arc, fill the pit and dial it down till the arc goes out leaving a smooth, rounded, fill where the pit was with a minimum size HAZ. I found that bead blasting did an adequate job of cleaning out the pits in preparatiion for welding.
I'm strictly a self taught welder and found that pit welding was not difficult after getting over the initial nervousness. However, I was not welding on a relativley thin, highly stressed shotgun barrel. That's a whole nuther deal and I defer to the experts in such situations.
OB
