Cam,
Generally, each pit is welded up individually. The surface should be clean and free of rust or any guck. Chemical cleaning and/or mechanical is used to either etch rust/corrosion or grinding with a rotary burr to remove any potential contaminants. Once welded up a barrel, I normalize the weld and the adjacent area by heating with a welding torch since I've encountered hard spots directly adjacent to the welding on some barrels. Then filing can be done without any difficulty.

Last edited by Chuck H; 02/20/07 09:12 PM.