Part of the process of tacking Mike's 29er. My apologies for some of the pregnant pauses as I make some adjustments to the jig and to the tig welder's settings as I come in/out of the frame but you get the idea. What you can see here though is how the jig rotates 360 and can be raised/lowered via a hydraulic piston. For the record, I hold my breath for the second tack (Head Tube/Top Tube) as it is a relatively tight place to weld and I do not want my inhale/exhale to move my hand while I'm in that tight spot tacking as my chest is close to my arm.
For the Tig Nerds out there, these were my settings:
Seat Tube / Top Tube: 53 Amps @ 1.7 PPS / Peak @ 60% / Background @ 20%
Head Tube / Top Tube: 61 Amps @ 1.7 PPS / Peak @ 60% / Background @ 20%
.0625 Lanthanated Tungsten, Gas Lens with No. 8 cup. (CK130 Torch)
.035" Weldmold 880T Filler.