Gents,Have to weld a 12 inch sch.120 pipe P1 to P1,can't pwht due to poor engineering design. Won't bore you with details. Would like to weld with inco 82. 1)Butter with inco,maintain 200F preheat,max interpass 350F using narrow weld beads to include HAZ 2)Blend butter passes with flapper and...