erratic arc

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Hope someone can help me out! I have a Miller 212 w/autoset mig welder. I use it in a farm shop, not daily. My problem is that every so often it will develop an intermittent arc. When it does this I can see a bright glow as the wire burns back. It never fuses to the tip and will continue to weld erratically, with an incredibly bright glow, which I assume is the wire burning back. Set the gun down and come back a few minutes later and it welds fine. Machine is relatively new and there seems to be no wire feed problems. I have had the problem with a previous machine so it is something I am doing, just don't know what. New tip and liner, same thing. It welds perfectly 90% of the time but really annoying when it acts up. Could it be the brand of wire I am using? I have played with the settings but does not seem to help. Anyway, any help would be greatly appreciated.
Reply:Flux core or solid wire? Is it the same spool that you had on the other welder?www.georgesplasmacuttershop.comPlasma Cutter and Welder Sales and Repairs--Ebay storeTec.Mo. Dealer Consumables for the PT and IPT torch's
Reply:A lot of people have this problem. I can't recall ever hearing someone solving it in a thread.I don't think I ever had the problem with flux core though.
Reply:I'm betting your ground connection sucks, grind a clean spot for the clamp to grab.
Reply:Sounds like a wire feed problem to me. If tip and liner are new, check that drive roll pressure is correct and that the grooves in drive rolls are properly aligned. Also check for excessive spool tension- should be just tight enough to prevent wire from unreeling when feed motor stops.As a diagnostic, release the drive rolls and pull several inches of wire out of the gun. If the wire is grooved or deformed, you have a problem with drive rolls or liner.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Issue always occurs with solid wire, has done it with different spools but always Forney brand. Thank you all for your help, gives me some things to look at.
Reply:Check your power receptacle and at the breaker and make sure all the connections are tight. I have seen this before were lose wires get hot and cause spikes in voltage.Last edited by mechanic416; 01-04-2016 at 07:58 AM.www.georgesplasmacuttershop.comPlasma Cutter and Welder Sales and Repairs--Ebay storeTec.Mo. Dealer Consumables for the PT and IPT torch's
Reply:While I'm not here to run Forney wire down, let's just say it wouldn't be my first choice...... there are better wires.  What you're describing can be caused by quite a few things, a lot have already been mentioned above.You didn't say, but I will assume you're using E70S-6 wire.  Again, you didn't say, but I will assume you're using 75/25 mix.  Two other possibilities - (1) If your farm shop isn't heated and cooled, condensation is your enemy and will cause minutes amount of rust to form on the wire and slowing begin to cause drag inside the liner, eventually stopping it up.  IF that is the case, I suggest after you're through with a welding job, remove the spool and put it in a air tight plastic bag and seal it up.  Even better would be if you had an old refrigerator you could then put that in too.  Then on your next weld job just reinstall it.  Yes it's a pain, but so are the feed problems you're now experiencing.(2) Have you ever fished with an open-face rod and reel?  Have you ever cast it and back-lashed it?  Damn near impossible to get all the tangles out, huh?  Well a lot of wires on the market are not layer-wound at the factory.  Therefore there is a much greater chance of the wire over-wrapping itself just as in the rod and reel example I mentioned.  But even in the layer-wound wires, depending on how they're handled, they too can get over-wraps in them.  Sometimes I've seen people grab a 44 # spool of wire and when they set it down on a bench or counter they'll slam it down.  All that does is dramatically increase the chance you'll get over-wraps in the wire.  Bottom line, the tangles and over-wraps won't allow the wire to feed smoothly and will cause the symptoms you're describing.Hope everyone's suggestions or these help solve your problem, good luck.
Reply:Originally Posted by 12V71I'm betting your ground connection sucks, grind a clean spot for the clamp to grab.
Reply:Thanks very much for your help everyone. AGW I think you hit it with the wire feed problem, tried another brand, put just a little more tension on the spool and the drive rolls and so far working like a charm. Again, thanks, I really appreciate it.