I have been doing pipe butt-welding with the TIG process (open root) under B31.1. I am interested in using backing rings and maybe changing the process to stick weld. Other than requalifying the process, does anyone have any comments on this? I have done some experimenting and it seems that the welding time is cut in half, the welds seem flawless when disected, and the ID is perfect as opposed to kind of lumpy (tubulant flow, etc). What about fatigue strength and such? Anyone got any experience with it?