Flux core and gases

A friend of mine just called, a novice welder, but a smart person. He asked me about his flux core machine. The wire wouldn't feed. We talked it through, and he wasn't taking the tip off when running new wire into the machine, and the end of the wire was not going through the small opening in the tip. Problem solved.

Then, he asked me about flux core, and gas and whether or not he should be using it together. He was. It was on a GS wire that was made to be used without gas.

I have used Argon with.072 FCAW wire for caisson welding, so know that you can use a gas with some flux core wires.

Questions:

If you use a gas with a wire intended not to be used with a gas, such as the GS, does it give you a gravelly appearance. That was what he said his welds were looking, appearance to him seemed his biggest concern. Then we got to talking about wires, as I thought he might be using a solid wire with no gas, and getting that crappy looking weld.

So, he went to the garage and looked and read me the numbers, and I looked them up, and told him the specs.

Just how forgiving is flux wire if you use it with a gas? Is it any better a weld if you do use gas? What type of welding would you want to use a gas with FC? And it seems they made the FC to weld without gas, so why now is it made for use WITH gas?

Thanks

Steve

Reply to
Steve B
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The flux formulations are completely different between gas-shielded and self-shielded flux core wires. They also run in different polarities. Self-Shielded runs DC Electrode Negative and gas Shielded run DC Electrode Positive (like MIG). Run a self shielded wire with a gas shield will make a mess, also running either wire with the wrong polarity will make a mess.

It will create weak welds likely to crack under stress.

Reply to
Ernie Leimkuhler

"Ernie Leimkuhler" wrote

Well, I got it right, anyway, telling him to use electrode negative for self shielded, and to turn off the gas. I just wanted to try to understand it a little better myself.

Thanks

Steve

Reply to
Steve B

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