Lotta good advice here.
If your Mig or Tig welds look like pieces of DOO DOO a couple things might be wrong.
I.E., wrong setting on machine, bottle, etc. , ignorance, old wire in case of MIG, particularly, wrong tungsten, wire and so forth. Most everybody knows a weldor with a good reputation nearby and some (hmm, maybe me, even) will weld for a bit of their favorite beverage . Seek them out. It's your a##, drivers!
Have on occasion done drag race tech and Bird-poo welds are cause for DQ in my eyes, even though the tubes are all dead plumb and perfectly fit. (Although sloppy fabrication usually goes with those kinda welds).