This video is about tig welding aluminum on AC at 50hz and at 250hz.
there was a noticeable difference at the 2 different settings. 50hz got completed penetration and 250hz did not penetrate.
I tried to keep travel speed the same for both welds by using a motorized welding positioner turntable.
Ck worldwide mt200 ac/dc tig welder set at 90 amps, AC balance set to 6 using 3/32" (2.4mm) 2% lanthanated electrode and 4943 aluminum filler rod.