what material and filler is that?? great shine to itIf you can get a nice flat plate around 3-4mm thick and practice some even straight runs directly on top of it. This way you'll learn a lot more. You'll get an understanding of how much current is needed to generate a pool on hot and cold aluminium (the difference is staggering) you'll also perfect the basics such as arc length and filler consistancy combined with consistant travel.
Joints like the one pictured above are not really going to help you progress as it's too advanced and your attempt of a weld on top of it shows that all too well. I've been welding aluminium full time for 15 years and I still go back to the beads on plate to perfect conditions when there is something new for me to do as I usually only get one shot to get it right so it's certainly nothing to be ashamed of. You'll get it I'm sure of that as your first attempts are going good but don't run before you can walk. View attachment 61671Get some of these laid on a plate and you'll be surprised at how easily the more technical joints follow.
Interesting vid. I kinda* get the improved arc stability with some of the natural oxide layer in place but the arcs cathodic cleaning action can't reach the backside of a joint or the edges of say a closed square edge butt for thinnish sheet. Scraping/brushing these areas usually makes a noticable difference to any oxide line on the root of the weldI've got a cracking video clip that I will try and upload that shows how ally actually welds better with a bit of oxide on it, that is why O2 doped gases work better than pure gases on aluminium
That would be good to see. I've never personally used O2 content in the mix for Tig.HR, not enough O2 to cause the tungsten any harm, I'll try and dig up another vid I have that shows TIG welds with doped gases