Hi Noel,
Are you left handed?
I see that the fish scale pattern on the open corner weld runs from left to right.
The 2.4mm filler rod did deposit a large bead but that is okay. The larger filler rod helps to cool the job as you weld so on thin metal it is a good idea.
The funny white boarder around the weld is a cleaning etch mark. The AC boils the alloy and all impurities float to the top and away from the bead. I see that the etch mark disappears and turns into a black carbon boarder on the right hand side. Also there is some pepper marks at the end of the bead on the right hand side. This can be avoided by better cleaning and more post gas.
If your electrode is blue after you have finished welding there is not enough post past flow.
On the T fillet weld it does look flat and that is a function of too many amps. The black spots are carbon due to lack of gas. Where the weld has started again near the black spots too many amps have made the bead widen. This is due to the increase of heat as you move along the job. A heat sink can help or if you have a foot control press all the way down to get the puddle formed and then easy back to half throttle. There will still be enough amps for welding but the heat will be reduced. The other way is to stop when the bead starts to widen, let it cool and start again.
Once you get the bead going it runs pretty fast so the heat sink is the way to go on thin jobs for me.
As Noel said keep the filler rod inside the gas shield at all times when welding.
Clean your filler rod before welding just like your plate.
When you stop or release the trigger hold the torch over the weld so the gas can shield the puddle until it hardens. If you do not that is where post pepper is formed.
When you get to the end of your run release the trigger hold the torch in position and keep feeding the filler rod into the puddle. This will fill the crater and prevent pepper.
Ji
