Mig wire feed problem

Are you using the correct feed rollers for the wire size? Have you replaced the gun liner to make sure it isn't kinked or crimped?

Try using a teflon liner to see if that helps. Curl the wire on wood to set the drive tension. Make sure the groove diameter is right. Will it run while just holding thr torch and feeding wire?

The feed rollers are the original ones, the roll of wire is the original and the gun worked just fine for several months. I have not replaced the gun liner and that may be the cure.

I used to do this: I had a MillerMatic 200 for twelve years. Fantastic welder. I used to ALWAYS buy .045 liners. They lasted a lot longer than .035, and didn't clog up or kink up.

Just my experience. Anyone else do that?

Steve

Are you sure the roller is turned to the right groove is running the wire?

If you can pull the wire with pliers..it means the roller is not holding it tight enough.

Gunner

Leftwingers are like pond scum. They are green, slimy, show up where they are not wanted, and interfere with the fishing.

Strider

wrote: (clip)squeezing the trigger, no wire is fed, until I grab it with the pliers and pull (clip) (clip) It runs just fine holding the torch and feeding wire. (clip) ^^^^^^^^^^^^^^^^^ I am confused. If you hold the torch in your hand and pull the trigger, without striking an arc, does it feed the way it's supposed to, or does the wire stall?

Friend of mine bought a Millermatic. He ran it for about 3 months and then it suddenly giving symptoms like yours.

As it turned out..he had been running it with the feed roller for a larger diameter of wire. Worked fine until the burrs and whatnot wore off. We figured it out, changed the roller and voila..back in business.

Gunner

Leftwingers are like pond scum. They are green, slimy, show up where they are not wanted, and interfere with the fishing.

Strider

Sorry my post wasnt' clear. Without striking the FIRST arc, the wire will feed fine. When the first arc is struck, the wire jams and I have to pull it out with pliers, making me think it's got something to do with heat.

Replace the contact tip and make sure the inside of the gas sheild is not shorted to the contact tip with spooge. Also..is your wire rusty?

Gunner

Leftwingers are like pond scum. They are green, slimy, show up where they are not wanted, and interfere with the fishing.

Strider

Hey Joe, Check the guide tube, make sure it is not too close to the rollers. To prevent birdnesting the guide tube ends up being set too close and causes improper feeding. Hope this makes sense.

Yup, that's my gues too- you need a new tip. If you've got a Tweco gun, keep in mind Tweco tips ain't the best in the world- sometimes you'll get one that's brand new and no good.

Make sure you don't have spatter stuck to the tip, that'll sometimes cause the wire to weld to it. You may find that rotating the gun will cause the wire to let go of the tip, works for me and it's a lot faster for the occasional stick than going for the pliers.

I got a two gallon bucket of Tweco tips, I met an old guy some years ago who worked in a place where they had a slug of robot welders and the operators pitched them on the floor when they swapped them out. He'd sweep up and pick 'em out for scrap, sold me the bucket pretty cheap and about 25% are perfect. I think they were helping him out with the scrap a little..

John

So this begs the question: can tips be cleaned up and reused? Can one use a grinder or lathe to get rid of the dirty section? Is the section that needs to be removed typically large enough to mandate a shorter outer cup? Is there a surface finish that grinding would remove?

Peter

I use a soft wheel to clean up the ends of contact tips, then run a proper sized drill bit through it from the backside by hand. I treat it like a brazing torch tip. Shrug. But then, Im a cheap bastard with more time than money. I just got done making a dozen contact tips from scratch for my old Airco 3ph welder.

btw...a softwheel is normally a 3M Scotch-Brite deburring wheel. Most machine shops use em, and toss em when there is still a fair amount of life in them. Stick one on a cheapy bench grinder, or even an arbor and run it with a drill motor in a vise.

I do machining, and machine tool repair. I find them invaluable around the shop for all manner of uses.

Gunner, preparing for the flames

Lathe Dementia. Recognized as one of the major sub-strains of the all-consuming virus, Packratitis. Usual symptoms easily recognized and normally is contracted for life. Can be very contagious. michael

Wrong size tip. I was running a .030 tip with .035 wire. When the tip heated with the first contact, it got bigger and grabbed the wire. This is a good newsgroup, not a lot of flaming, and I've lurked here for a while. Gotten several good ideas. Thanks, guys. We all benefit when we help each other.

Sometimes it is the most obvious thing.

DOH!

Steve

Thanks for the feedback -- it helps me learn from others mistakes (that way I can go invent new ones instead of reusing someone else's).

mikey

The one good thing about repeating your mistakes is.... you know when to cringe.

Gunner

Rule #35 "That which does not kill you, has made a huge tactical error"

wrote: (clip) When the tip heated with the first contact, it got bigger and grabbed the wire. (clip) ^^^^^^^^^^^^^ I have been puzzling over this ever since you first posted it, and I am very glad you found AND POSTED the solution. Just one remark: More likely it was the wire heating and expanding that caused it to seize. A hole has the same coefficient of expansion as the metal it is in. Heating the tip would make the hole bigger.