So..........this is my first attempt at welding sheetmetal. Hopefully the pro's will provide some constructive criticism that myself and others can learn from.
I'm practicing on 18 ga using a Lincoln 135sp with .023 wire and C25. I suspended the pieces off the table and gapped slightly with the magnets. Tacked extreme left then right, blotted with a damp towel, hammered them down a little, then repeated the procedure the center, then split the gaps 2 tacks at a time.
After a little hammering the piece is relatively flat at this stage. I'm thinking (guessing)

there is too much wire on top and not enough penetration but the heat looks close.
Rookie work bench
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Input is much appreciated.