Mig polarity and other stuff...long...sigh

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Gunner Asch 20 years ago

Some time ago, I traded into an absolutly MINT Arco PulseArc 350 mig welder. Only problem was..I made the deal before looking at it closely and when I got it home, discovered it was 3 phase. Sigh... So I loaned it to a friend who I guess never used it.

I got it back a couple weeks ago, and tonight I decided to try to see if it would run on 1phase 220. I could get the fan and controls to work..but no arc, by supplying 220 to two of the three leads. I didnt try to put power on 1 and tie 2 together. Shrug.

So I put a longer power cord on it, and plugged it into my 5 hp 3phase rotary converter, which brought it to life. I had to futz with the drive rollers, and play around with wire speed and amps before it would actually start to run a bead with that frying bacon noise..and not ratsnest the wire in the wire drive. I noticed I was getting burn back, and while the beads looked great..I had nearly no penetration. It worked and sounded wierd. That machine has some sort of pulse mechanism in the arc, so wrote it off as that. Until it hit me....I was using straight wire, no fluxcore with 75/25..and so I checked. Sure as s*it..the machine was hooked up electrode negative. (sound of Gunner slapping his head..hard)

A quick change over..and voila..it runs a great bead, with good flow of the glassy smooth puddle with a hell of a lot less amps, and I can see good burn into the parent metals. Still has a wierd sound to the arc though and is picky about wire speed and amps adjustments, even with a consistant stickout distance. I was even able to weld a couple pieces of .060 sheet metal together..which surprised the s*it out of me as Im using .035 wire. And for me..thats damned good cause Ive never claimed to be anything more than a low grade dauber. And no back plate either.

Anyone have one of these? Any hints on setting it up? The amp dial goes from 0-35, which has no corresponding marks, but there is are amp and voltage dials..which are of some use.

Another question...Ive got at least 3 BIG rolls of .045 Dual Shield and the proper contact tips. Since this stuff is flux core, to be used with shielding gas..do I leave things electrode positive, or do I swap it over for normal flux core polarity..electrode negative?

Im also having a small issue with something that I cant quite understand, and it may be related to having the thing running off a RPC. Or maybe its just being a newbie without a clue...

At low currents, like the sheet metal above..it tends to sputz out a bit of wire before the arc gets really well established and starts to melt. About an inch or so, Now Ive never used pulsed mig before, and as I understand it..this is spray transfer(?) and the wire never is supposed to be in the puddle? This welds far differently than my old Dan Mig, even the arc is differnt, not counting the sound with that hum in the arc. Im used to nearly dragging the wire in the puddle and this has the melting zone a fair amount above the puddle..which is strange to me (but then..I wake up in a strange new world every day ) This bit of wire is not melted into the puddle. It may stand proud sticking out of the bead at the first, or coil up a bit. Its really disconcerting and it may be the result of too little amps set at the output via the amp dial ? Do I need to crank up the amps and live with a hotter arc than I think there should be? Or am I being fooled by the sound/sight of the pulsed arc and am thinking Im really cranking out the power where Im actually not?

And lastly....the amp control goes from 0-35. It seems that with the .035 wire Im using, it gives me a good arc at around 22-25 with a very fast wire feed. The amp gauge shows around 100-125 amps. and about 25 or so volts. If the welder is 350 amps..shouldnt that be a lot higher amps? Or is there some relationship between the wire size and what the arc actually "draws" and if I left the amp setting at the same place, but ran .45 wire..the arc would "consume" more amps and the amp gauge would read higher?

What am I looking for when I both first start an arc, and when I run it, visa vis arc length, sound and so forth? Pulse is totally new to me and is quite different than short circuit type mig.

Thanks

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the s*it out of you for torturing the cat." Gunner

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ATP* 20 years ago

There are a few sites that relate wire speed, size and voltage to current.

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has some decent explanations and a forum run by the cranky but knowledgeable Ed Craig. You are correct that larger wire will result in more amps given the same wire speed and voltage. The size of the welder is really not relevant until you get to the maximum output, ie the same wire size, voltage and speed will run the same amps on a 250 as a 350. I would try the unit without the pulsed feature and get the spray settings down first. With regular spray transfer you should have more argon in your mix- 92/8 will get you into spray mode at lower wire size/speed. You need at least 85% argon to achieve spray transfer at reasonable current levels. I don't have a fancy pulse welder but I think the same would be true for pulse.

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dcaster 20 years ago

The dual shield that I have is run DCEP and will do spray transfer with

100 % CO2. It is Rockmount Polaris. I like it, but it is not wire I did a lot of reseach on before I bought it. It is from Boeing Surplus. Ernie likes Esab dual shield which I will try if I ever run out of what I have.

I think that most dual shield is run DCEP.

Dan

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Gunner Asch 20 years ago

There is no Pulse Off/on switch. This beasty was made in the mid to late 1980s, when the technology was prett new.

There are two user adjustable controls on the power supply. Amps and off/on Which kinda sorta makes it better as one doesnt get confused trying to figure out what all the knobs and doofunnies do.

Will 100% argon work better than the C25? Can I use CO2?

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the s*it out of you for torturing the cat." Gunner

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ATP* 20 years ago

My limited understanding is you need at least 8% CO2 for heat and penetration. More CO2 moves you up the chart as far as the amps needed to get into spray. The pulse stuff I haven't used. I have an old ESAB 250 CV unit that came out of a New Holland Skid Steer factory. I just got a new wire feeder, a Miller 22A which I'm setting up to replace the ancient feeder it came with. Tomorrow morning I hook up the gas and I'm ready to go. Spray is nice when it works right. Very clean and the arc pulls into corners, etc..I want to try some low alloy metal cored wire next for a little more versatility.

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Gunner 20 years ago

Addendum..sigh...the control on the front is Volts..not amps. Brain fart yet again on my part.

Gunner

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Ernie Leimkuhler 20 years ago

Airco PulseArcs are kind of shunned by the welder repair guys I know. They all detest them.

If yours runs and works fine, then congrats, but if it dies, just use it as landfill.

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ATP* 20 years ago

OK. Amps are controlled indirectly by the wire feed setting.

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Gunner 20 years ago

My buddy who also is a welder repair guy said pretty much the same thing. Though he has now found a reliable guy who repairs the boards at a price slightly less than "first born child".

I trailered it over to his place and showed it to him, and when I mentioned the price I paid..he scratched his head...shuffled his feet, and called me a slightly vulgar name, then asked me if I wanted to sell it....

Gunner

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Gunner 20 years ago

Sigh...brain fart again. My buddy brought over the front lead cover for this Airco Mig, which Id left behind...and its NOT a PulseArc...but an Airco PhaseArc 350. Whr\ere I got pulse from..Ive not a clue.

Big big difference...

Ok...what is this? A regular mig? Spray Transfer? Big Orange Bubblegum Machine? No reference on Google except mine from when I got it..and I ID'd correctly then.....sigh.

Still has a hum in the arc, still seems to do spray rather than short-ciruit arc.

Blink blink...Ive been off my heart meds .....mumble mumble twitch...

Gunner

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ATP* 20 years ago

Sounds like a regular constant voltage MIG. Short circuit vs. globular vs. spray transfer is a function of voltage, wire speed and shielding gas- the same machine will do short circuit at a lower voltage setting or globular in between.

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Wayne Cook 20 years ago

Based on the post stating the voltage went up to 35 I'd say it's a regular MIG but it's got enough voltage to go into spray arc mode if desired.

This just depends on how you set the machine and to a lesser extent what kind of gas you're using. High voltage, high wire speed, plus high percentage of argon gas equals spray arc mode. Lower voltage, lower wire speed, lower percentage of argon gas is short arc mode. In between the two is a no mans land of globular arc and other bad juju.

I forget what size wire you're running but figure something along the lines of 16-18V for short arc and 25-35 volts for spray (lot of variables there). Wire speed is more difficult but figure 9-11 o'clock on the dial for short and 1-3 o'clock for spray as a starting point. Fine tune from there.

The weld reality site mentioned before can give more info on this.

This is similar to my Miller Dimension 400 in the learning curve. Since you've only used smaller machines with a max voltage of 28 or less learning to turn the voltage dial down to the low side takes some getting used to. Just be aware that spray arc can do bad things to the contact tip if you mess up. Of course it's not as bad in your case as it is in mine. I setup mine for spray arc the other day and let my hand use it. Only I had someone distracting me at the time and forgot to turn up the wire speed. He ended up melting 3/4" off the shield cup not to mention totally turning the contact tip into molten metal.

I was using it earlier this month on a big stainless job and had trouble with arcing to the contact tip occasionally. With 500 amps available it only took a couple of seconds for contact tip to turn bright red and sag. I finally figured out my problem there was the fact that I was using a 98-99% argon 1-2% CO2 mixture which is perfect for spray arc mode. Unfortunately the stainless I was welding was to thin for spray arc. The high argon mixture combined with the short stick out needed for proper short arc in stainless made for a bad combo. I didn't have any tri-mix and I didn't have time to get any so I had to go with what I had. It was a bad time especially when combined with trying to push the soft 0.035" stainless wire through a

25' gun (I ended up cutting it down to 20') with the wrong rollers (I had the rollers ordered earlier but they ended up being back ordered till the day after the job rolled out of the shop). I had a lot of birds nests till I finally hit upon using one 0.045" roller with a 0.023" roller. Even after that I had some feed problems from time to time which would blow a tip when it happened. Overall the job ended up costing me about twice as much as I made on it if you count the sudden need to buy a new plasma cutter (the old one pooped right at the beginning of the job).

Wayne Cook Shamrock, TX

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Mig polarity and other stuff...long...sigh

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