x_25, your cutting/fitting isn’t great. You can’t weld air, and you can’t weld dirt. However I don’t think that’s your biggest issue. I got a Harbor Freight 170a wire feed welder and used it with flux core wire for about a year. It was always a porous, spattery, filthy mess like what your pics show. I finally manned up and got an argon tank and a $25 regulator off of Amazon to do real MIG- night and day difference. I’m laying clean, shiny “stacked dime” beads like in the videos.

Flux core SUCKS. Seriously. Get an argon tank and some good quality wire from the welding supply store. You’ll wish you had done it sooner.

My experience was the same with flux core. MIG became a delight after adding gas.

I'll double that.

I've seen people lay down acceptable welds with flux-core wire. Hell, I've seen people do amazing, TIG-like welds with a stick machine.

I am not one of those people, and I can only assume that it takes hundreds of hours of experience to reach that level. Which I don't have.

And, yes, welders with a 120v 15a input are anemic at best. Has nothing at all to do with the quality of the machine, there's only so much power you can extract from that supply.