Yesterday night was my GTAW class. We did butt joints the week before: a 1/16" gap between 16-gauge and a 3/32" gap between 11-gauge plates. There was a shortage of booths last week, so I had to wait until people finished, which cheated me out of time. I did a decent 16-gauge butt joint, but I ran out of time for the 11-gauge. It did nice cover passes but I couldn't get the weld to penetrate properly.
This week there was another booth shortage. I started on an old TIG machine but quickly jumped to a new one when possible. It took a few tries, but I ultimately got the key input from my teacher: when the keyhole forms, you'll get solid penetration.
And I sure did!
All our butt joints tonight were subjected to bend tests: placed a U-shaped jig then mashed down into that with a hydraulic press. My two pieces--weld face and weld back--passed, as you can see: weld intact!