Oof, those welds are ugly. The author comments on the welding at the end of the article, but I'd venture a guess that if using a MIG setup the polarity may also be reversed and/or gas shielding may be wrong. On my machine the flux core wire vs solid core wire with shielding gas require opposite polarities...
source: I'm a terrible amateur welder
Yes I'm using flux-core wire and I do indeed have the polarity set for flux-core.
My conception was that we're adding power by increasing the voltage and we're stacking up material by adding wire, so to get good penetration on thick material I want lots of voltage and not much wire feed.
But actually it turns out that you make it hotter by increasing the wire feed speed.
I don't really see why, but at least now I know.
Here's a more recent weld: https://img.incoherency.co.uk/6464 - still not great but not nearly as bad.
Nice weld, and nice project!
I'm learning with you.. the polarity was fresh in my mind because I recently got half way through a project with little bb's splattering everywhere before a friend with more knowledge asked if I had recently changed wire.
Welding seems to be a lot like baking; It is very deterministic in a sealed environment and the parameters are well understood, but in practice the experts rely heavily on feel and experience more akin to an artist.
I haven't seen welds that bad since visiting India, where I ran across some so dire I was compelled to photograph them in case the building fell down later: https://imgur.com/a/16FRlEW
Love the spirit of the build, though, and it's a case where weld cleanliness doesn't really matter, so, more power to him.
the last section discusses this. the author was having problems relating the feed and the current settings to the weld characteristics. personally I prefer to manage all that with a pedal and manual feed with a tig