[bomccorkle]

Today I cut some seats out of an old flat bottom john, since I had the scrap laying around I figured I'd go ahead and piddle, first off I am using an old miller dialarc HF, 26 torch, gas lens, 1/16 2% lanth electrode, strait argon shield gas at around 15cfh, the material is about 1/16(no idea of alloy) and using 4043 3/32 filler rod machine in 40-190 range about 125 amps floored. My question(s) are, I'm sure my lack of knowing my base alloy is a hindrance but then again just piddling. I noticed that my base metal was cleaning just right at arc strike amps and that my arc also had a tendency to wander, also (thus may be to bad filler angle, but my filler was melting damn near before I could get it into the puddle. Also I would think I may have been into the pedal maybe 25% to get a puddle(I figured I would really need some heat to burn off the oxide layer?) Anyways I guess in general I'm asking if this sounds fairly normal and if I am heading in the right direction?

[Otto Nobedder]

Today I cut some seats out of an old flat bottom john, since I had the scrap laying around I figured I'd go ahead and piddle, first off I am using an old miller dialarc HF, 26 torch, gas lens, 1/16 2% lanth electrode, strait argon shield gas at around 15cfh, the material is about 1/16(no idea of alloy) and using 4043 3/32 filler rod machine in 40-190 range about 125 amps floored. My question(s) are, I'm sure my lack of knowing my base alloy is a hindrance but then again just piddling. I noticed that my base metal was cleaning just right at arc strike amps and that my arc also had a tendency to wander, also (thus may be to bad filler angle, but my filler was melting damn near before I could get it into the puddle. Also I would think I may have been into the pedal maybe 25% to get a puddle(I figured I would really need some heat to burn off the oxide layer?) Anyways I guess in general I'm asking if this sounds fairly normal and if I am heading in the right direction?

For 125 amps, you should have a bigger tungsten. 3/32 should do.

Look at the ball on your tungsten. Is it off-center? Is it larger than the tungsten? When you get too hot for the tungsten size, you can actually see the ball dance around on the end of your electrode, and when you stop you'll find the ball larger than the tungsten.

Steve S

[aeroplain]

Many boats are 5000 series, the 4043 is good, but like Otto said, go up to a 3/32 electrode, Pure or Lanth.

[bomccorkle]

Thanks for the help, the electrode had a fairly uniform ball it formed itself on the tip, will step up electrode sizes and give it another whir, I typically only really mess with fairly thin material, less than 1/8 usually. Will I still get a fairly crisp arc start with the 3/32?

[Braehill]

If your machine is set to the 40-190 range and you floor it, you're getting 190 not 125 and that starts flirting with the need for 1/8.


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[rick9345]

(need some heat to burn off the oxide layer?)

oxides don't burn off, they float and get in the way
Its HF that starts the arc and allows low amp AC to blast them off,not the heat

[MinnesotaDave]

(need some heat to burn off the oxide layer?)

oxides don't burn off, they float and get in the way
Its HF that blasts them off,not the heat

High Frequency does not provide the cleaning.

The positive side of the AC wave does that, the negative side provides the penetration.

The high frequency keeps the arc going during the zero crossing point in the AC wave.

AC wave.jpg (59.99 KiB) Viewed 1058 times

[bomccorkle]

If your machine is set to the 40-190 range and you floor it, you're getting 190 not 125 and that starts flirting with the need for 1/8.


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The machine has a zero to 100 dial to tweak in appropriate amperage within given window.

I had understood the dcep was what pulled the oxides from the workpiece but had thought that the oxide layer was a high heat to get it to start "moving" I see now, after burning a bit; of course, that it seems to me that just lighting up and warming the area to float then remove oxides, then rolling in with pedal to wet, then dab filler, then move foward, lather rinse repeat. I'd assume nice new stock would prob move along better, but I think I'm beginning to get the gist of what I'm seeing thru the lens.

Tig has become unbelieveably addicting, like a 9 year old with an Xbox. Aluminum now working with it especially so, tons of stuff happening there.....

[Otto Nobedder]

...just lighting up and warming the area to float then remove oxides, then rolling in with pedal to wet, then dab filler, then move foward, lather rinse repeat....

That's the ticket. Blast the full 190+ just for tacking, a 3/32 can handle that for short bursts.

As you said, when ready to weld, run a fairly low current to build heat in the area, until you see stuff float, then amp up and feed. Be prepared to back down as you progress, as the heat will continue to build ahead of you. Your description could match my method with aluminum.

Steve S

[Braehill]

You're correct about the dial on the panel being able to control the amperage within the range selection. When you're operating a foot pedal or remote amperage control it is adventagous to set it to 100% to get full control with the remote. I can't see limiting yourself to a certain amperage within the range while welding Aluminum, but that's just my opinion, you can do it your way if it works for you.

Len

[bomccorkle]

I see what you are getting at Len. I had thought, and maybe incorrectly that dialing back the dial/amperage would gibe me more refinement with the pedal, but once again I'm new to the tig bit and will give it a go your way next time and see how it works out.

As always thanks for the help guys

[Braehill]

You were correct in your thinking, it actually does refine the amperage adjustment as you're dividing a smaller range by 100. My point was I don't think it's really a needed benefit for Aluminum as it's nice to be able to have full power at the start of the puddle because it actually puts less heat into the part. If I'm welding really thin steel or stainless I'll do as you've done and set it lower to obtain a more precise range of adjustment.

What you were doing is not wrong, just not as beneficial in my opinion, and it's just that, my opinion.

Len
P.S. I've used that same welder since 1982 and I bought it used (1980 model year) and only put one part in it the whole time I've owned it.

[bomccorkle]

I do definitely see where you are going with the mass heat influx as to minimize heat soak. When lighting up hot and fast like that will it cause the contaminants to just "pop" out? Sorry for being ignorant, I just fond it much easier when I kinda know what to expect.

And on that machine I came across it on a steal, I happened to be in my lws as it was being traded in, it was a unit from the local 4h club it looks pretty damned new still and the guys from the lws told me they hadn't sold them but a couple of electrodes and cups in the last year or so and it mainly just saw stick duty, I scored it with a 25' 26 torch, they threw in a couple gas lenses and collet bodies, a couple boxes of cups, a box of 1/16 electrodes and a couple pounds of filler right around $800.

Like I said I just do automotive work mainly and really couldn't justify the outlay on a new machine but when they gave me a price I had them roll it in the truck.

[Otto Nobedder]

...And on that machine I came across it on a steal...

Yes, SCORE!

And we'll be happy to help you make the most of it.

Steve S

[Braehill]

It's actually the cathodic action of the A/C current that does the cleaning, it bombards the oxide layer that's always present on the surface of Aluminum. This oxide layer melts at nearly three times higher temps than the underlying metal, but being very thin, it gets nearly vaporized in the ions (basically a plasma)flowing back to the electrode. This starts happening a soon as the arc initiates and continues throughout the whole weld and is not entirely dependent on amps. Your welder has a 50-50 balance of DCEP and DCEN so at 60 hz, this happens 120 times a second. That dull whitish-gray line that forms on either side of your weld is evidence of this cleaning.

There're other threads if you search this forum with probably way better explanations of this than I've presented here, but that the basics of it. Others, please feel free to correct anything I have wrong here or needs clarified.

Len

[GreinTime]

I mean technically, if measuring peak to peak on one side or the other of zero to get a 60hz frequency, the EP cycle would only take place 60 times start to finish per second... Just saying.

[Braehill]

That's true. It passes through the zero point 120 times but only cleaning on 60.

Len


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[bomccorkle]

I see. Thanks for the clarification sirs. Things Ade happening that I thought, just not quite in the manner I had thought. Thanks again.

I'm sure I'll have plenty more questions to come....