You are using plenty of gas if the gauge is reading correctly. 25 is a lot and a waste imho unless you are outside and there is a slight breeze.(anything more than a very light breeze and you are headed inside) In the shop 15-18 is quite adequate.
Your tacks/stitch are not interconnected, leaving a lot of pin holes which can lead to weld failure from vibration and flexing over time.
When you start a new tack - start it so that the wire is right on the edge of the existing tack. Hold for just a moment then move slightly away from it.
When done correctly it will look like a nice oval shaped tack laying slightly over the previous tack and you wont have a pin hole in between them, just a continuous weld.
Be sure to keep the wire centered on the gap. I try and hold the gun at 90 degress to the weld, and tip the gun 10-15 degress toward the exisiting tack. I make the tack either round or oval, then move to the opposite side and do it on a cool location.
I do not do the 5 tacks in a row for the reason that it is dam hard to get 5 tacks all with good penetration, consistant size, and centered over the gap when zapping away.
In this picture of your tacks I have circled in red what appears to be the first tacks.
Then the first green circle to the right of the red circle is your second tack.
These 2 are a great job, just what you want !
I put in more green circles to show how I would continue across the seam. I might have to many green circles as it is hard to scale , so it might less than shown.
Another tip to get good penetration: When you have made a tack that is a bit thick , instead of just trying to melt into it, grind it down to the same height as the normal tacks. You will get a far better start, better penetration, and less risk of burn through.
When we weld pipe using wire , whether it was x-ray or not we ground a small relief on the start and end of every tack or stringer. Wire doesn't "dig in" like stick and the thinner the start zone is the easier the tie in . A slight gap, about the diameter of the wire is the best. Doesn't take near the heat to get full penetration since you are only fusing to the edges and not melting the panel through to get penetration. This technique is a bit harder to do , but gives a full weld with less haz.
In sheet metal work the haz is what it is all about, keeping it as small as possible while maintaining full penetration. Less distortion and warpage is the result, as well as less material to grind off, which again means less heat put into the panel.
The use of a flange weld is great for spot welds, but when used for stringers all a flange weld really does is require much more heat to get full penetration and a resulting warped panel.
I'll get off my soap box now, LOL
Have fun, you are getting there! SOF.
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