Help with TIG technique pls.

admin

Hello,I'm doing a TIG welding course at night school. I'm one weld away from completing the course but just can't get it right.The weld consists of joining 2 halves of a pipe together. The weld is vertical and for this weld I am unable to rotate the pipe, I must weld from the bottom to the top or vice versa.My problem is that I just cannot get penetration or reinforcement inside the pipe at the bottom of the pipe, or in other words, when I weld the pipe from underneath, looking up, I can't get penetration inside the pipe. My instructor says I'm suffering from "suck back".I've fiddled with the argon flow rate, filler wire sizes, current, timing everything, I just can't get this weld to work.If anyone has any suggestions I'd very appreciative.
Reply:Suck back is caused by to much heat so move a little faster and try not to stay in the same spot for to long hope that helps you out a bit.. it would also be a good id to posttype of materialpipe sizesfiller amps  etcCigweld Transmig 265seBoc 140amp StickBoss 200amp AC/DC TIGLincoln Electric Invertec V260-S
Reply:For the 6 o'clock position, 3/32 filler, loose 3/32 gap....the slightest back and forth movement of your arc inside the width of your gap while feeding approx. 3 times the length of filler to distance travelled.  Feed slightly above bevel points and watch to see convex bead profile develope on the outside.  Experiment by trying the extreme and seeing how much wire you can work into the puddle.