Zac skip-welded the reinforcement in place to prevent heat concentration and potential warping. This also reduces heat buildup and possible embrittlement of the welded area caused by welding.
You can see the electrode and the electrode cup that dispenses argon gas that acts like a shield to keep the oxygen in the air from oxidizing and weakening the weld.
Tig Welding has a nice smooth sound not all crackly like Mig welding, that is unless you are AC welding aluminum or something.
Next, it was time to weld in the front lower control arm pivot relocation kit. The first step was to cut off this part of the subframe flange that would interfere with the lower control arm bearing.
Here is the cut once it was done.