Gas with innershield

A long time ago in another galaxy, I used an argon shield with a .072" wire.
It must have been required by the specs.
Yesterday, I was playing with some inner shield on my Miller 180. The
puddle looked good, but had quite a bit of porosity and sponginess to it.
Dark grey in appearance. I turned on the CO2, and it looked slightly worse.
Then I fried a tip, and, not having a replacement, was done for the day.
I do have some 25/75 mix. Is there any reason to use a gas with
innershield? Does it improve appearance?
Also, the root was open between two pieces by 3/16", so I had to bridge it.
It still came out spongy. Does not having a good closed root that somewhat
blocks air from getting into the back of the weld cause this porosity?
I did change the polarity from hard wire, so that's not it.
Wifey is picking up some contactor tubes for me today, so will try it again.
Overall, the weld did not look that good, and was thin. I know I can make a
bigger puddle, and travel slower, but I'm afraid I might reach the limits of
this machine. The cover panel has parameters for up to .045" wire. (Maybe
.040", but whatever the next size up from .035" would be on this machine.
Reply to
Steve B
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Self Shielded Flux Core (Lincoln Inner Shield, ESAB Core Shield) does not use gas. Polarity DC Electrode Negative
Gas Shielded Flux Core (Lincoln Outer Shield , ESAB Dual Shield) uses gas. Polarity DC Electrode Positive
Reply to
Ernie Leimkuhler

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