mig and flux core tips and techniques, equipment, filler metal
JoeSparks
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    Thu May 17, 2012 9:08 pm

I'd been having difficulties getting consistent welds with my Northern Tool MIG welder. Went through the instructions again to see what I may have overlooked. While I was going through the setup again, I noticed that the instruction book and the instructions pasted on the inside of the welder are different in one critical way. The polarity marker on the wires at the panel are reversed in the directions. I changed the polarity and it made all the difference in the welds. I realize this may not happen with more upscale welders but as was noted in another thread, switching back and forth between gas and flux welding can leave the machine in a wrong state for the weld you are making. Crappy welds? Check the polarity again.
CraigLam
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    Sun Jun 17, 2012 1:52 pm

Absolutely, Joe. They teach you that in welding school. You can also go on line to welding videos and they help alot, too. Do you know why the polarities are reversed when using mig or flux core? Funny you should ask. It takes more current to weld with NR-211 (flux core) or inner shield. The gas shield come from the flux inside the wire. In mig welding, the gas shield comes from the argon gas which which takes less amps. So what? When you are welding, you are using an intense magnetic field. As you know, DC current travels from minus to plus. That makes the plus side (the nozzle) have more current and thus a deeper weld. It literally won't weld, or weld very good, on the minus side-not enough current. Thusly, welding L-56 on the plus side is too much current. I'm not sure what's was goin' with your mig welder why is was incorrectly labelled.
Here's a good tip. When welding with NR-211, back off your weld and increase your ESO to about 5/8". Only on 1/16" metal and heavier. Go slow and watch your puddle and not the spark. Practice a little every day. And post photos. You have real professional welders here and it's a good idea to take advantage of that. Turn and Burn!
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