[NylonAdmiral]

Hi guys, I've been MIG welding for a while and have just bought myself a TIG. I found that DC welding steel/stainless steel wasn't as hard as I'd expected to get started with and feel like I've begun to get to grips with it relatively easily. I mainly bought the TIG for the aluminium jobs I need to do though and have so far have found it pretty tricky!

I'm a hobbyist learning on my own so would really appreciate some input from some of the more experienced welders on this forum!

I'm currently practicing with some 2mm aluminium sheet I have. I've found that I can get a pool started on a flat piece of stock, then start creating a bead across the workpiece. It's by no means a work of art but it's got the basis of something I can hopefully develop into an acceptable weld.

The problem is that as soon as I go to do either a butt or a lap weld, everything starts to go horribly wrong and I can't get a bead to start taking shape.

My setup is:

R-Tech TIG161 AC/DC 160amp Inverter TIG.
Fresh, 1.6mm ceriated electrode.
2mm aluminium sheet.
20cfh pure argon/10sec post flow.
4043A filler rod.
Base current 55amps (a welding calculator suggested 65-70 but I think that was for a non-inverter and it turned out to be too high anyway).
No pulse.
Approx 55% AC balance, approx 110hz AC frequency.

I've checked most of the common "newbie" mistakes which I've found online. I'm holding the torch at about a 15 degree angle with my filler rod 90 degrees to the torch, I've cleaned the workpiece extensively by grinding the top oxide layer away or scrubbing with a stainless wire brush, then cleaning with acetone. I've used various "welding calculators" to get the setup right. I've tried using a chunk of aluminium billet as a heat sink.

Although I'm currently using these settings at the moment I've tried various other combinations and the problem seems to persist.

What I seem to find is that although welding on flat stock is OK, as soon as I actually go to weld one piece of stock to another, the edges sort of curl away from each other. This seems to be worse if I do an internal corner weld too.

You can see from the attached shameful image what I mean. The beads on the flat bit are taking shape but the edges look horrendous when I try and join one piece to another.

What am I doing wrong? Any help would be much appreciated!

Is there something wrong with my setup or is it just that I'm bad at welding aluminium?

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[Rick_H]

Outside corner joints are going to be the hardest for a newbie to alum, fitup is important. You need to get the puddle fast and start moving.

Try turning the amps up a little and when the edges start to curl dab some filler, and keep moving. If I am understanding correctly it just sounds like you are expecting that nice looking puddle, you won't necessarily see that on a butt or corner type joint.

2mm sheet is thin to learn on, some thicker stock maybe easier to build beads on which will help get the feel.

[NylonAdmiral]

Thanks Rick, I'm not necessarily expecting a nice puddle, I was just expecting something better than the horrible mess you see above ha ha!

OK, so with the possible exception of tweaking the amperage, it doesn't sound like there's anything fundamentally wrong with my setup or my method, it's just that what I'm trying to do is pretty difficult? Possibly one of the harder types of weld to do, with a difficult thickness of material?

It sounds like the best thing to do is maybe get some thicker stock to begin with and practice, practice, practice?

Thanks for your input.

[cjohnson98]

The biggest thing that I had to learn when welding aluminum is that you have to be consistent and roll with it! Also position yourself to where you are comfortable and stead! After you get the puddle started on both pieces just keep dabbing to get a rhythm going! Also it helps if you practice feeding wire too! Use the pedal to your advantage because aluminum heats up very quick, especially thin material! You will get the hang of it, it just takes practice!

[Boomer63]

I think that everyone has some great ideas, but my suggestion would be (as Rich_H) suggested, try some thicker material. I would try something double the thickness of what you have. Clean, clean, clean your surface, preferably with a stainless steel wire brush and some cleaning compound (like acetone). You are probably already doing all of this, but I had to say it!

Arc balance .. to me that varies from machine to machine. I have some Miller machines and we all seem to like the balance at about 73.

Again, try thicker metal. Work your way up! Check back in when you do that!
Gary

[NylonAdmiral]

Thanks for all the tips. Gary, I've wire brushed/acetoned everything to within an inch of it's life! At first I thought that cleanliness was the problem but I'm sure I'll have another look at the balance, when I turned it up that high before it quickly burned back the electrode but as you say I guess it's different between machines.

CJJohnson, I've been finding that the pedal certainly helps yes, I just need to get more experience of using it and coordinating two hands and one foot together!

The thing that I've found is that when trying to form the weld pool, It's almost like the material right at the join doesn't heat up enough but the metal a few mm either side of it does. I can't figure our what I need to do get the arc into the tight gap as it seems to just sort of go wherever it feels like!

I've just been out and bought some thicker stock to practice on as well so will try that this evening.

Thanks for all the input, it's much appreciated!

[AndersK]

Your corner looks just lile mine did when starting to learn aluminum. I figured out later that I didnt used high enough current and tried to add filler way to early. You have to wait until you see a mirror puddle, and then quickly add filler before it curls away too far.

Was doing some 1,5 mm butt joint yesterday, at 75 amps. Backed off a bit after some distance when pieces got soaked of heat. Current control is crucial on thin aluminum so if you dont have a foot pedal try and learn to use up- and down slope and pulse with torch trigger.

I have a practice piece that was initially 4mm thich. After laying bead after bead beside each other its now 35 mm thick.
That help you learn consistent feed and travel.

I have yet many more hours before I get fully comfortable with thin aluminum.

[GreinTime]

Thanks for all the tips. Gary, I've wire brushed/acetoned everything to within an inch of it's life! At first I thought that cleanliness was the problem but I'm sure I'll have another look at the balance, when I turned it up that high before it quickly burned back the electrode but as you say I guess it's different between machines.

CJJohnson, I've been finding that the pedal certainly helps yes, I just need to get more experience of using it and coordinating two hands and one foot together!

The thing that I've found is that when trying to form the weld pool, It's almost like the material right at the join doesn't heat up enough but the metal a few mm either side of it does. I can't figure our what I need to do get the arc into the tight gap as it seems to just sort of go wherever it feels like!

I've just been out and bought some thicker stock to practice on as well so will try that this evening.

Thanks for all the input, it's much appreciated!

Try setting your balance at 30% instead of 55%. If your saying the tungsten burned away at a higher number then your machine is set up like an Everlast and you are adjusting Electrode Positive. Miller and Lincoln machines are changing the Electrode Negative.



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[GreinTime]

Looking back at your pictures, that is definitely the case. Your cathodic etching (white frosting) is almost as wide as the weld bead on both sides.

In this instance, you are getting your joint hot, but not using usable heat and just trashing the edges. Try it after you turn your balance down below 40 and see if you get the same results.

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[LtBadd]

Are you sure your material is 6061 or 5052?

[Oscar]

If your fit-up is nice and tight you can blast it with 120-130A for an eye-blink duration and that will get a small quick tack, which you can then weld much easier. If you have too big of a gap, then you might be able to set the amps very low and let the cleaning action clean the edge, then puddle it and as soon as it gleams silver, dab the edge to build it up and bridge it to the other side. Not ideal, but it can save the piece at the expense of possibly dumping in too much heat, especially if it is a toy-size practice piece.

[BigD]

The biggest thing that I had to learn when welding aluminum is that you have to be consistent and roll with it! Also position yourself to where you are comfortable and stead! After you get the puddle started on both pieces just keep dabbing to get a rhythm going! Also it helps if you practice feeding wire too! Use the pedal to your advantage because aluminum heats up very quick, especially thin material! You will get the hang of it, it just takes practice!

This, as a fellow newbie that's a bit further down the road, just keep practicing. If you have any doubt if it's the material, the gas, the machine or cleanliness or anything else or you, it's you. As a beginner it's too easy to lie to yourself about the arc length and torch angle, both of which are not very important with MIG but CRITICAL with TIGing aluminum. As others have said, chewing back edges isn't automatically bad. Thin stuff will do that, you just have to immediately add rod and keep moving. This can be hard to learn from MIG which dumps filler for you. Also if you're like me, you will have a tendency to lengthen the arc when adding filler, which itself isn't bad but then you will stay far away and start overheating and get frustrated.

Another thing that I find experienced guys don't emphasize enough is that you have to hit aluminum hard. Don't bleed on the heat. Jam it hard to get it to puddle, add rod, back off if needed and move out immediately. It's hard but once you get it, it's extremely satisfying and then when you try steel, you will drool at how easy it is.

[NylonAdmiral]

Thanks for all the input.

I bought some stock which was literally only about 1mm thicker than that stock I was practicing with and it seemed to make all the difference. I think I was just getting ahead of myself and trying to weld something which was too thin for my limited experience.

This was my first two attempts with the thicker stock:

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I feel like these were much better already!

One problem I find still persists though is that sometimes, I'll be mid weld and things will suddenly go bad, even though I can't see that I'm doing anything different. You can see what I mean in the picture below, working from right to left, I start getting a reasonable weld going, then it suddenly changes. Is this because I'm doing something wrong or is it something like I've hit a patch of contamination?

20160218_202306.jpg (60.71 KiB) Viewed 1373 times

The things which I've really learned so far is how much the amperage requirements change according to the material thickness and how much heat is in the workpiece. I'm starting to see the necessity for good pedal control.

Your cathodic etching (white frosting) is almost as wide as the weld bead on both sides.

How wide should the etching be?

Thanks again everyone!

[motox]

maybe you touched the tungsten or lost your vertical torch angle or
moved the torch away from the material (tight arc)
craig

[Poland308]

When things go bad for me it's usually sloppy angle. When it happens make a mental note of how stressed your hands are or if you were getting to the limit of your motion. Another good one is if your cords or lead start to drag. The extra resistance against your hand motion can be enough to throw off your travel or will pull the torch off to a bad angle. In a lot of Jody's vids you will see him do a dry run to check if it's comfortable and to make sure nothing is going to get snagged or caught.

[BigD]

Yep, it's the torch angle. It lengthens the arc which increases the heat and starts washing out a bigger area. This is another bad MIG habit where the torch angle doesn't really matter so it's OK to rotate the torch to finish up the weld and not slide it laterally. With TIG, esp with alu, you have to become like a robot, sliding down at a constant pace and angle. You'll get it, already clearly improving!

[NylonAdmiral]

Hi guys, I thought I'd come back and post again in case anyone else comes to the forum with the same problem that I did.

Thanks to everyone's input I've now figured out exactly what was causing each of the problems which I initially asked about. Through trial and error I know for sure what was causing each problem so thought I'd share those findings.

The original problem with the curling edges was definitely caused through inexperience with such thin aluminium but also because the amperage was too high. I subsequently realised through some practice that the amperage needs to be just high enough for each edge to start to turn to that "silver mirror" you're looking for, then as the workpiece starts becoming saturated with heat the amperage will be just enough so that the edges will melt together and a dab of filler can be added.
Unfortunately, I had the amperage set way too high to begin with. I'd used an online welding calculator to determine what I thought was the appropriate amperage but it turned out to be too high.

The second problem which was the bead sort of falling apart mid-way through the weld (as shown in one of the later pics) was caused by poor gas coverage which itself was because I wasn't being machine-like enough and my hand was wavering and varying the distance between the tungsten and the work piece. As I practiced more I was able to maintain the correct distance between the tungsten and the workpiece without worrying that I would touch it with the filler rod. I also practiced making sure that distance remains constant.

Once I figured out these two problems my aluminium welding instantly got better. You can see the picture below of two different welds. I'm not saying it's anywhere near as good as some of the craftmanship posted on this forum, but for two weeks practice and no tuition at all, I feel like I've figured out how to get an acceptable weld. Now I just need to practice a lot more and work on consistency I think.

Thanks again for all your input, I wouldn't have figured it out without your help.

IMG_20160227_160410.jpg (67.4 KiB) Viewed 1312 times

[Oscar]

Nice. Now ditch that brass-plated carbon steel wire brush and use a SS wire brush.

[Rick_H]

Nice. Now ditch that brass-plated carbon steel wire brush and use a SS wire brush.

You sir read my mind and have good eyes...

[NylonAdmiral]

Nice. Now ditch that brass-plated carbon steel wire brush and use a SS wire brush.

That brush isn't for welding. I've got three of those floating around which are just for general workshop use. I've got two wooden handled wire brushes which both have stainless steel "wire". These are the ones I use for for welding, one is for aluminium and one is for stainless steel, neither are lurking in the background of these pics because they hang up out the way of any possible contamination, it doesn't really matter what happens to the plastic handled ones

[GreinTime]

Nice. Now ditch that brass-plated carbon steel wire brush and use a SS wire brush.

You sir read my mind and have good eyes...

Are you guys referencing the brush in the picture or the odd bronze color on some of the ripples in his weld?

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