This is part 2 of a 6g tig pipe welding test video project.
Part 1 was prep work, fitup, tack welding, and root pass.
This is part 2 which is the hot pass.
The term hot pass is very misleading with tig welding because the hot pass is rarely any hotter than the root....at least not by much. In this video 120 amps was used for the hot pass...same as what was used to weld the root pass.
For the root pass, I used a tig finger and moved the arc forward and back with no intentional sideways movement. Any sideways motion has a tendency to make the root pass flatten out.
I am after a root pass that protrudes a bit...is a bit higher than flush.
...and the main goal of the hot pass is to add defect free weld metal that does not disturb the root pass.
why would you want to go to great efforts to weld a nice root only to screw it all up on the hot pass?
impatience is a foe to deal with here. you need to let the pipe joint cool down to nearly room temperature before attempting the hot pass.
If you let it cool, you have a better shot at not disturbing the inside of the root.
I used 120 amps for the root pass and I also used 120 amps for the hot pass.
A 1/8" rod (3.2mm) using the "lay wire" technique was also used.
On the hot pass, I walked the cup. when you use the walking the cup technique you need to make sure to use the right cup size.
In this case, I welded the root pass with a #6 gas lens style cup but that was a bit small for the hot pass so I switched to a #7 cup and that allowed the cup to rest in the bevel without touching the metal deposited on the hot pass.
see part 1 of this 6g tig pipe welding video
see more tig welding videos