TIG issues on aluminum. Arc wanders unless I use more amps (then it's too quick)

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JohnnyK81
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TIG issues on aluminum. Arc wanders unless I use more amps (then it's too quick)

Post by JohnnyK81 » Thu Apr 21, 2022 7:47 am

Hi guys,

Trying to teach myself aluminum TIG welding. While I'm new to this particular process, I'm ok with other welding, and mild steel on TIG seems to be ok (albeit not great, but, different problems).

The issue I am having (I am just practicing on 1/8 aluminum), is once the puddle starts, she starts melting too quick. I am set to about 100amps (As per machine instructions. Any less and the puddle seems to take too long to form). By quick I mean, I don't think you could feed filler rod that fast unless you were a machine.

BUT, If I back off the pedal, the arc starts jumping around erratically. But once you press the pedal back down, the arc concentrates, but once again it starts melting too quick.

Metal is cleaned, filler rods are cleaned (not a filler rod problem obviously, but), acetoned, brushed. Tungsten is freshly ground longitudinally. Argon at 10-15cfm.
Machine is just a Hobart Ez-tig 165 so no real adjustment (Ac/Dc, amps).

Summary: Any thoughts? Basically, I want to be able to back off the pedal to slow down the melt rate so I can feed material in, but if I do that, the arc starts wandering. Is the whole piece getting too hot? I can't see that being the case or everyone would need to keep waiting to finish an aluminum bead.

Thanks guys!

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GlennW
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Re: TIG issues on aluminum. Arc wanders unless I use more amps (then it's too quick)

Post by GlennW » Thu Apr 21, 2022 9:15 am

Heat control on aluminum is a bit more critical than steel. It needs a bit more patience to get a puddle to form than steel does. It sounds like you are going from too much to not enough on the pedal when trying to get a puddle formed.

It needs fine movements of the pedal to maintain a puddle.

It may not be the correct way, but I only set a heat range on the machine and use the pedal to control the amperage. In other words I very seldom, if ever, set the machine to where I am welding with the pedal flat. I always have it set to where I have more heat than needed to weld and use the pedal exclusively to get the desired amperage and maintain a puddle.

Back off on the amperage and take more time to get the puddle formed, and pay attention to the surface of the aluminum as it heats up. You'll see a bunch of what looks like shiny spots or tiny puddles start to appear just before the actual puddle forms. Take it slow until you can read what is about to happen and you will learn to anticipate what is about to happen.

It's a lot easier to demonstrate to those new to aluminum than it is to explain!

Just to make sure, is your high frequency set to "continuous" instead for "start"?
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

JohnnyK81
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Re: TIG issues on aluminum. Arc wanders unless I use more amps (then it's too quick)

Post by JohnnyK81 » Thu Apr 21, 2022 10:13 am

Thanks Glenn. Hobart/Diversion 165 so no HF control, no nothing except AC/DC switch, and an amp dial (and a foot pedal). Even gasflow is preprogrammed.

Maybe you are correct on my foot control (there's a lot going on with a TIG weld. :) ) So you are saying, give it the beans to form a puddle, then let off the pedal a bit to slow it down once it has formed and I'm moving?

(On the bright side, this is my first time trying again since I got the jolt of a lifetime about a year ago. I suspect my ungloved (at that time) filler touched the electrode? Not sure what caused it. I'm pretty much in full on body armor this time!)

Thanks again!

jwmelvin
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Re: TIG issues on aluminum. Arc wanders unless I use more amps (then it's too quick)

Post by jwmelvin » Thu Apr 21, 2022 8:04 pm

Is the piece small? That makes things a lot harder. On 1/8” aluminum I’d be running 150 amps at least. The faster you get the puddle going the less heat you put into the piece overall.

LIALLEGHENY
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Re: TIG issues on aluminum. Arc wanders unless I use more amps (then it's too quick)

Post by LIALLEGHENY » Fri Apr 22, 2022 12:11 am

Lets start off with some basics. Welding light wall aluminum TIG you want the machine set to AC. One amp per thousands of material thickness, so 1/8" (.125) is 125 Amps. One thing you mentioned is the tungsten was "ground longitudinally" .....on AC TIG you want a ball on the tungsten, NOT a ground point. To ball the tungsten set the machine to DC electrode positive and using a piece of copper (not your steel welding table) hit the pedal and you can create a ball....then set the machine back to AC. You should be using 3/32" tungsten and a larger cup than you would for steel as gas coverage is more critical . 15 CFM, no less. Use a flow gage if you have one.
This is my recommendation as practice, bring the heat up slowly until you create a puddle, play with it backing off till the puddle solidifies until you get a good idea of how to control the puddle. There is no time limit, play with the puddle as long as you need to till you feel you have a good control of things. Once you get that down, start adding filler wire, again on/off with the pedal till you can control the puddle , then start laying a bead. Once you get a feel for that than start welding a "basket" . Lay a bead in a circle, say 2" in diameter. Then lay a bead on top of the previous, and so on. Once you can start to build up a wall than you know you have good control over what your doing.
One last thing, if you can get a high frequency unit for your machine, do so, it makes life so much easier.

Nyle

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GlennW
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Re: TIG issues on aluminum. Arc wanders unless I use more amps (then it's too quick)

Post by GlennW » Fri Apr 22, 2022 5:46 pm

Are you using Pure or Zirconiated tungsten?

Thoriated doesn't like AC.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

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