Welding Tips and Tricks

So I'm practicing with some self-shielded flux core wore,.030" Hobart wire. It had no issues on a millermatic 130 but I switched to a transformer 211 due to power issues. I've run it at a variety of different voltages and wire speeds and have tried both .030" and .035" contact tips and nozzle gel. I am running with a nozzle since it is my schools and it helps keep everyone from shoving the tip an 1/8" from the puddle. The problem I keep having is the wire getting caught or something somewhere. This has happened about a half dozen times know. About twice it has been welded to the contact tip but the rest of the times the wire came out of the tip okay with a little cleaning. The wire hits the liner on the inside of the machine and bends around it and then snaps about 3/8" away from the beginning of the liner. Then I have to pull out the wire and feed some more wasting a bunch of wire. I don't know what the problem is. I have a strange suspicion that it had something to do with spatter build up and get rid of the nozzle or something like that or I made and observation about the liner. (I would've taken a picture but I forgot to go back to the room.) The liner seems to have a slight bend in it in the 1/2" that isn't in the gun or it could be bad wire. Bad wire is my lest option since it ran fine in the 130. If nothing else I guess I'm getting good at changing contact tips sometimes and putting wire in a gun.

Sounds like you're describing a "birds nest"

Generally this is because the feed roller tension is too high so the rollers are unable to slip if needed.

Using the correct knurled feed rollers, the rollers need much less pressure to feed the wire.

Pinching the wire with a gloved hand should be able to stop the wire without a birds nest occurring - the rollers should slip.

After having a few birds nests, sometimes the liner gets bent near where the wire goes in and the liner must be replaced.

Also, after the wire breaks it can become slightly tangled on the spool. Like when fishing line is wrapped badly.
This can cause feed issues.

Yeah, what he said!

Saw that often enough in a shop where we used multiple sizes and types of wire. Guy would slap a spool of .045 flux core in after a spool of .035 hard wire, lock it down and everything suddenly would go from awesome to berzerk. A machine that was awesome 10 minutes ago was suddenly a piece of crap!

Well Dave thank you for that information. You mentioned ire drive tension. I watched a handful of videos on flux core and the weld.com with bob m brought that up and I made sure that wasn't a problem. He did it where you bend the wire and then pull the trigger and it slipped. You also brought up knurled drive rolls. I set up the machine for flux core since my teacher wants me to do more manage mtn things around the shop and since if I don't do it, it may not be done for awhile. I asked my teacher if he had any knurled drive rollers cause I heard that before and he said hat I must be pulling his leg since he had never heard of it. So I went along with it and put the drive roller it had in it in for .030" wire and called it good. I may look and see if the 130 had a knurled drive roller that can be switched over. Once I burn through this roll I'll see about a new roll that isn't twisted any. Seems like with the machine 6 foot in the air and with a small area for he wire to go into its hard to put wire in and out without a problem. (70-80 lb transformer up 6 ft ain't fun nor a 80 lb Airco sick welder that's 18" wide 4 feet up in. 17.98" wide hole.)

Your teacher never heard of knurled drive rollers???

Since flux core is hollow it crushes easily. The heavier pressure of smooth rollers can flatten it a little and cause feed problems.

When the rollers randomly slip the wire can burn back and melt to the tip, then the bird nest occurs.
That's only one possible problem.

With the proper rollers it takes barely any pressure in comparison to feed it.

My teacher isn't much of a welder. He can out two pieces of metal together decently. He's more of a woodworker and machinist.

Farmwelding wrote:My teacher isn't much of a welder. He can out two pieces of metal together decently. He's more of a woodworker and machinist.

Then show him what I wrote so he knows.

Plus it's right in tip #1 here:
http://www.bernardwelds.com/tips-for-av ... K-sklMrJdg

I did notice that it said the liner may be bad if bird nesting. I felt some vibration in the gun like there was some kind of resistance. Is this a possible problem?

Farmwelding wrote:I did notice that it said the liner may be bad if bird nesting. I felt some vibration in the gun like there was some kind of resistance. Is this a possible problem?

Yes, it could be getting plugged, or the incorrect rollers are squashing the wire into an egg shape and causing the problem.

Chasing problems always starts with using the correct equipment.

Alright verdict is in. I will request new drive rollers that are for flux cored wires or see if we have one. Thanks all.

Well my teacher ordered a knurled drive till since we didn't have one. I adjusted the wire feed tension and ran about 6 in of weld and sure as crap I ran out of wire. I told my teacher to pick up .035" Lincoln wore since I've heard Hobart wire had issues feeding which may have been part of our problem and thicker wire with a bigger machine.