Following as I've had really spotty luck with my mini welder unit (Miller 130) turned way down too.
One thing to note more generally with wire is that the E71T-GS wire is very loosely defined while the only slightly more expensive E71T-11 has a more reliable specification. I wouldn't use the GS; I accidentally bought it once and I'm like wtf is wrong with my alleged technique and then I realized it was probably the wire.
I just commented on this over on WeldingSite.
Here and
Here. Short excerpts:
My favorite is INETUB BA71TGS. (.030 for welding thin material.)
https://www.amazon.com/BA71TGS-030-Inch-2-Pound-Gasless-Welding/dp/B003E2RF0E
It feeds more smoothly and welds with less smoke (so you can see what you're doing) and less splatter outside the weld area, compared to others I've tried.
This is made by an Italian company specializing in top quality welding products, so its definitely better than any bargain generic wire.
Inetub is the only GS-spec FC wire I will buy. Because GS means whatever secret ingredients they chose to put in it. In contrast, T-11 wire is a known, specific spec. Lincoln's NR-211 is T-11 spec.
Price for Inetub is comparable to other quality wire - and half the price of Lincoln's NR-211, considering Lincoln's small spools are only 1 lb.
Camelcamelcamel, a price tracker for anything on Amazon,
can email you a notice next time this on sale.
Definitely start with quality wire until you have some experience, to reduce the number of variables you have to figure out!
As for burn-through: last week I made some practice welds on old rusty .060" sheet metal, ground clean at where I joined it. This was with my HF MIG-180 (turned way down) and what was already in it, Inetub .035. I didn't have much problem with burn-through so long as I kept moving. A couple of instances in a half hour of tinkering.
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