[outofround]

Hello all,

I'm a moderately experienced aluminum welder who recently purchased an inverter machine (Miller 280dx), having not used one since working at an aluminum fab company many years ago.

I have been using it to weld on AC with success but one thing I have been noticing is that when I turn up the frequency too high (let's say up to 180 hZ or so) my electrode seems to instantly consume itself/deteriorate as I start my arc and try to get a puddle going. I am using a 2% ceriated ground to a dull tip, have been hopping between a 3/32" and 1/8" diameter on 1/4-3/8" thick material with the same results using both electrodes. I've been experimenting with balance between 60% and 70% or so.

Higher balance percentage seems to help but I can't seem to keep my electrode clean unless I turn my frequency way down, at which point everything seems to lay down just fine.

Have any of you ever had this experience? Any tips or info on what is happening? I don't remember having this experience. I can say for sure that I don't seem to be contaminating my electrode by dipping it into the parent material, the electrode just seems to eat itself up and retreat back to the cup when I try to start that arc.

[TRACKRANGER]

Hello all,

I'm a moderately experienced aluminum welder who recently purchased an inverter machine (Miller 280dx), having not used one since working at an aluminum fab company many years ago.

I have been using it to weld on AC with success but one thing I have been noticing is that when I turn up the frequency too high (let's say up to 180 hZ or so) my electrode seems to instantly consume itself/deteriorate as I start my arc and try to get a puddle going. I am using a 2% ceriated ground to a dull tip, have been hopping between a 3/32" and 1/8" diameter on 1/4-3/8" thick material with the same results using both electrodes. I've been experimenting with balance between 60% and 70% or so.

Higher balance percentage seems to help but I can't seem to keep my electrode clean unless I turn my frequency way down, at which point everything seems to lay down just fine.

Have any of you ever had this experience? Any tips or info on what is happening? I don't remember having this experience. I can say for sure that I don't seem to be contaminating my electrode by dipping it into the parent material, the electrode just seems to eat itself up and retreat back to the cup when I try to start that arc.

Thanks for the level of detail, this always helps

1:
How many Amps?

2:
Re: " the electrode just seems to eat itself up and retreat back to the cup when I try to start that arc":
This reads as though that only take a few seconds? In that case, are you sure the electrode is locked into the collect tightly and is not slipping?

3:
What polarity are you using EN or EP? It could be that your leads are reversed.

Oh, and welcome to the Forum

Best
Trevor

[outofround]

I'm not sure how many amps. I typically leave my welder turned up fairly high and keep my foot where it needs to be. I would guess with the thickness of material I'm working with in the 190-270 range for a puddle.

I thought maybe my leads were reversed as well, but that is not the case. Also, I'm fairly sure my collet is tightened down. I'm using a gas lens.

But yes, you are correct that this is happening pretty much instantly. The one thing I haven't had time to do is run out and grab an extra pack or two of electrodes, so I suppose it could be that the tungstens themselves are bad. I don't know, thought I'd throw it out there and see if anyone else had any other suggestions.

[noddybrian]

There are many more experienced that will jump in on this but random thoughts at first read of your issue are probably too many amps for tungsten diameter assuming your up above 200 on that material - maybe a not great batch of tungsten & Jody swears by 2% Lanthanated on AC - I think maybe higher frequency shows up more issues than 60hz like the older transformers - but my biggest pointer is you say only when starting so I have to ask is your PRE-FLOW sufficient - if you have no or very short pre-flow & hit 200 > 250 amps before the argon has had time to envelope weld / tungsten area it will vaporize it much like trying to weld without gas ! ( ask me how I know !!! )

[taz]

I am not familiar with that particular welder but I recall it has something to do with the blue lightning settings.
Maybe someone that owns one of these miller welders will comment.

[weldin mike 27]

Is it possible the gas is bad/wrong?

[Bill Beauregard]

I have a 280DX. I usually use a 1/8" on anything that thick. I have a variety of tungsten including thoriated, ceriated, lanthanated, tri mix. I haven't tried zirconiated. Only using very dirty metal would I get below 70% EN. I've heard that frequency over 300 could damage the boards, so I stay below 250. I can't think of an occasion where I would want 250 with 1/4, or 3/8". This variety of machine will push the limits of 1/8" tungsten. Go even bigger, or don't grind except to clean tungsten. You can go DC EP on a piece of copper, or very low on AC EN to round the tungsten. This surprisingly, focuses the arc into a narrow cone. I usually want a narrow focus. Don't ball the tungsten, just round the end.