Guys, I am by no means an expert welder, but you should be able to get a decent weld with co2 on a mig. You have to hold the nozzle close enough so the gas can sheild the weld. Try turning your reg up a little for some more gas flow. If you want a cleaner weld go with an argon co2 mix for a few dollars more, or even straight argon for no spatter but it is spendy. Gas is much better than the flux wire belive me once you get the hang of it you'll only use the flux wire in an emergency.
Bob DuPuy Parrish, FL