Having some trouble on outside and inside corner welds, getting the puddles from the two parts to come together as one. Especially when trying to do an autogenous tack, but also when using filler.
Like this mess here, for example. I could not for the life of me get the two sides of that weld to come together.
But sometimes I have no problem at all and can make nice tacks on outside corners like this:
Which is almost as frustrating, because I'm not sure what I did differently to make it work so easily.
Once I get things started, I can run a reasonably nice weld (I mean, ignoring the tip dip and getting too hot at the end--at least I know how to fix those things

TIA for any suggestions. I've tried searching here and on YouTube, but I haven't come up with the right combination of search terms.
Setup:
1/8" Al, wire brushed and acetone.
2018 AHP AlphaTIG 200
#5 standard cup. 3/32 2% lanthanated tungsten. 125amps. 120hz. 35% balance. Foot pedal. 12-13 CFH argon.