backroads wrote:I have add'l pics. Per your recommendations, these changes and verifications have been made:
1. verifies AC aluminum light lit
2. verified 100% argon
3. torch leak: none
4. set balance to 70%
5. amp setting 150
6. flow increased to 20 cfh
7. freq verified at 120 Hz Thanks to all of the helpful responders, I am making progress today & feel good about making the settings per your advice. Pics to follow:
the middle pic tells the story. i can't read the writing but right hand side looks like low amps standing around waiting until the metal overheats and falls out. middle bead more amps but still not enough to really get a puddle flowing. left side looks like more amps and getting puddle to flow.
i would suggest setting it higher amps than you need so you can get the puddle started better and get it to flow down into the root. then back off as you weld when it starts getting to hot and the puddle starts getting away from you.
The leftmost fillet weld is better too. The bit of porosity in the middle, that’s from the rabbit hole. That means you are leaving a triangular gap at the root of the two pieces because; your arc length is too long, You’re not hot enough, or your adding filler too far in front of the puddle. I’ll wager #1 is your cause. And that’s common with less experienced welders.
What I’d suggest is that you set your tungsten length beyond the cup to be equal to 3x the thickness of your tungstens. This lets you get the tungsten tight to the material, get the correct puddle, and add filler and watch it fill the root of the fillet. This is not easy to do, and you really need to focus on this as you go.
Yep keep hanging in there! It took me months and months of practice to get this joint happening and regular trips to oz's version of home depot to pick up yet more Al flats to practice with, but just keep bashing away at it and you'll get it. You're already speeding along compared to what I was doing. I have the crappiest AC tig setup on this forum and I can do some ok fillet joints now, so you'll have no trouble. Once you do get it down, you'll be hitting that root and getting the puddle flowing down the joint (the most important parts of this weld) without even thinking about it. Just remember that Al seems a lot more reluctant to work with you on fillets and corners compared to mild steel, so it's gonna take more skill and effort on your part, but it will make you a better welder overall for it.
Don't be scared / too disappointed to have regular soot bombs from when you dip the tungsten in the puddle - at least it means you're biasing to running a short arc which as cj737 said, is better than a long arc for this joint, which leads to incomplete fusion because the sides have melted first instead of the root. You might still end up with a decent looking weld with a long arc, but the root won't be fused.
If it does feel like you're never going to get it, drop the filler and double - hand the torch and do autogenous welds. The priority is to learn to get the root properly fused. Get that happening and then try and do autogenous welds one - handed, once that's happening then add the filler hand back in. Al particularly fillets is definitely a game of sweet spots, too little is as bad as too much - you need enough heat to get things started properly but not too much, you need enough filler to plump up the weld but not too much etc etc (particularly when adding at the start of a fillet)
But all the advice in the world won't substitute for practice and basically teaching yourself as you're doing - we all have slightly different hand movements and co-ordination so what may physically work for one from a learning perspective may not work for another. Perseverance and never say die is the key.
I just scanned over the top of these posts, but one critical thing to be mentioned (may have been already) is make sure haven't contaminated the aluminium withe steel. Like with a steel wire brush or a grinding or sanding disc that has been used on steel. It'll stop the puddle from flowing and cause all sorts of issues.
