Bigger rod on a bigger welder might be faster, but it's not going to produce a better weld than a smaller welder with multiple passes that's done correctly. I'm not a welder by trade, but I get to enjoy burning some metal from time to time. I learned on a Century welder back in the 80s after first learning to push a puddle with a torch. I've been fortunate to use some nice mig and tig welders over the years, but my stuff has always been on the cheap end. I bought a used Century 250 amp AC welder from a coworker for $20 before upgrading to a brand spanking new AMCO 160 amp DC welder from amazon. It may be crap compared to a real welder, but I actually love the little thing. I normally run it on its 220v setting just to keep from tripping breakers, but since I don't run it over 120 amps, I could get by with 110 if I paced myself a little better. If it has to hold, I generally grind a bevel, lay a root with 6011, and layer in with 7014. My results aren't perfect, and aren't always petty, but they are stronger than the original material and work for my needs. Most of my welding projects involve my old 1710 tractor and firewood, or my truck and trailer for the same purpose.