When mine was working (before i threw it at the junkyard whereit belongs. horrible piece of ----). the best thing to do is:
use the correct .023 self-shielding wire
high amps
medium-> medium/high wire feed speed
use a pipe expander (the cheap HF ones work for awhile...)


The .023 wire is ALOT closer to what you need for the typical super thing fence post/conduit bullshit exhausts weve all built, and welding a small fillet weld with a machine putting out way too much power for the base material (and not enough for the wire itself) is easier than doing the same on but-welds. You'll blow alot fewer holes in it and possibly get to do some welding!!!

 

i did a little bit of welding at my last job. .052 dualshield is fun lay some fatty 1/2inch welds down, muahahaha.

but yeah, slow down a bit and steady your hand. its kinda hard to give advice over the internet. its a lot easier to get hands-on help from an experienced welder. have fun doing verts