[Kelvin le Roux]

I have been welding MIG and Stick for a long time now and recently decided to get into the TIG world. I purchased a Digital Inverter TIG welder a cylinder of argon and all the other necessary consumables. The first time I tried it out I found it challenging however I was successful in creating what I consider fairly good aluminium welds for a first time on TIG. The problems all started two days later when I tried it out again. See image Bellow:

Final Result

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The oxide layer never gets broken and all the aluminium inside melts. Also forms black soot on and around the weld.
Take note I started with the default settings of the machine and then altered each one (to all extremes) with no improvement.
What puzzles me is the fact that it worked for one day and not at all thereafter.

Welding mild steel is flawless with a perfect smooth arc.

Mild Steel Arc

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Ive added images of the aluminium arc:

Aluminium Arc

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Aluminium Arc

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I would really appreciate any advice or feedback.

Bellow I list the settings used:

Pre flow: 0.5s
HF Start
Arc Start: 20A
Up Slope: 0.5s
Welding Current: 110A
Clearing Depth: 0 (Goes from -50 to 50%) - I Have tried values right throughout the available range with no effect.
Clearing Width: 30% (Goes from 10 to 90%) - I Have tried values right throughout the available range with no effect other than the fact that the arc dies out at values above 70%.
Frequency 60Hz
Down Slope: 0.5s
Arc End: 20A
Post Flow: 2s

Gas: 100% Argon (Gas flow rate has been adjusted right throughout the flowmeters range with no effect or improvement)
Tungsten: Zirconiated (Lanthinated doesn't seem to be available here - I reside in South Africa)
I don't have a gas lens
Machine: Pinnacle PrimiTIG 208p

[cj737]

Material thickness? Set your gas flow to 2x the cup size. Hit the material with full amps to break the oxide layer, then taper off to deal with not melting the internal metal.

[Oscar]

Yes,material thickness is very important, as most beginners don't use nearly enough amperage. Your aluminum might be anodized also. That needs to be removed if so. Also, you might be on DC instead of AC, changing the clearing width should affect the white etching around the weld bead when you adjust it to give you more cleaning effect. So you say it worked fine one day, and not the next. Let's see the bead you ran the day before. Also, what were the exact settings you used the day before on the bead that did run fine?

[BillE.Dee]

can you show us a picture of the front of your machine? If you have the 2t/4t switch in the wrong location you wont have any pedal control of the heat. The freq you are using (60hz) will get you a lot of heat at the weld. The balance, which may be different on different machines will get you the "cleaning" action you are looking for to penetrate the oxide layer, which you may want to scrub with a stainless brush (in one direction) and then wipe with acetone or similar cleaner. You would probably notice if the balance is wrong by watching the tungsten disappearing if it is set improperly.

[Kelvin le Roux]

Thanks you for your responses.

I have been experimenting for the last few days and will attach the results.

My material is 2mm thick.

At the moment I do not have a foot pedal, only a finger switch on the torch. I will get a foot pedal as soon as possible though. I use both the 2t and 4t settings.

The first time I used the machine I didn't even clean the material however that is when I got the best results. The settings for my first weld were about the same as what I posted in my first post if i remember correctly. Understandably there is grime and stuff in the weld as well as large etching area etc - but its a weld - which is more than I can say for my more recent endeavours. See image bellow:

First welding attempts.

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Since this I've never gotten the weld beed to even begin to form even though I have meticulously cleaned the material and tried every setting combination you could imagine.

This morning I was experimenting some more and found that the only way to get the oxide layer to melt at all was to get the tungsten within 1mm or less of the surface of the material and use relatively low amps (50A). This resulted in it being very hard to add filler material and made it very easy to dip the tungsten in the weld-pool. Very frustrating. If i pulled the tungsten away at all the arc would either die or the base metal would melt a wide pool and fall out bellow - depending on the amperage set. I was using 200Hz AC frequency for this. See the results bellow:

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The Weld is about 3mm wide. Around it you can see the carnage of other attempts...

The balance setting I'm using results in a bit of balling but not a lot, only the point of the electrode balls.

Attached bellow are images of the front of my machine.

Machine

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At this point I'm wondering if something hasn't gone wrong with the AC function on the machine or if my gas isn't bad...? Would appreciate your advice before I spend more on this.

Thank you.

[Oscar]

IMG_6368.jpg

Oh, I've seen this before. I think I know what your problem is. But we have to play the guessing game since it was not disclosed previously: How did you acquire this "aluminum"? Can you absolutely positively identify what alloy it is?

[Kelvin le Roux]

The aluminum was just off-cuts from a friend. I can’t identify the exact alloy. I have used the original piece a few times since my struggles started with no success. That is what made me rule out material because I was able to weld a piece one day but a few days later was unsuccessful on the same piece.

[DougW]

Are you welding inside shop/garage or outside?

You're 30% EN cleaning.... with a range of 10%-90% what your machine it actually giving you is EP values. You need to change that to ~65-75% and you'll probably be able to start welding.

[Oscar]

The aluminum was just off-cuts from a friend. I can’t identify the exact alloy. I have used the original piece a few times since my struggles started with no success. That is what made me rule out material because I was able to weld a piece one day but a few days later was unsuccessful on the same piece.

I would question your definition of "successful". I would bet your "aluminum" is zinc-infused pot-metal. Even then, I think the main issues is not knowing what the machine is doing with these settings:

Clearing Depth: 0 (Goes from -50 to 50%) - I Have tried values right throughout the available range with no effect.
Clearing Width: 30% (Goes from 10 to 90%) - I Have tried values right throughout the available range with no effect other than the fact

I think you were perhaps changing too may things at the same time, and then got lost. It happens to a lot of beginners. Go out and BUY a brand new piece of 6061 aluminum from the hardware store. You won't be able to diagnose aluminum TIG welding issues without good aluminum. Also I noticed your amperage is pretty low unless you have a piece that is less than 2mm. Couple that with the fact that you were using 200Hz, that severely reduced the actual total heat input into the metal. Turn the AC frequency down to 50Hz, and note the difference. With aluminum you need a lot of initial amperage. But still, that won't overcome anything if you don't have weldable alloy of aluminum. As to whether or not the AC function of your machine works, only you would know since we are not there to watch/listen to the arc. You can always find a way to post a video.

[BugHunter]

If he's saying he went back to the diamond-plate and still can't get a clean puddle, maybe his torch is now so filthy it's contaminating the welds. If there's a bunch of gunk on the cup, I've seen that cause all sorts of black bugs.

I tend to agree on buying a piece of clean 6061. Then you know what you've got and should expect good results. The diamond-plate is probably a 3000 series alloy which should also work fine. The tungsten needs to be clean, and that can't be stressed enough.

[Aquamoon]

Hello Kelvin, did you come right with this issue, I have the same machine and struggling quite a bit.

[cj737]

This thread is 4 years old. I don’t expect the OP to respond. You should start a new thread, post a picture of your results, and list the settings you are using. Also, a picture of the front of the machine when ready to weld helps.