Back up a step,
As a guy who used to work for airgas selling these things, let me set some goodness straight.
1. You should not have to use an oversized tip for hard wire, This may not hold true for flux core as I have expereinced wire swell with .045 flux core wich we would jump to an .052 tip. Stick to the same tip as your wire size for hard wire.
2. drew is right on the tips, If you are not using gas use the hard tip, not the open cup, Not really a big deal, but with flux core you will throw more spatter, This will get stuck in the gas diffuser (the peice that the tip screws into) and when you do get a tank and run gas it will run like s***. You can use the open cups (gas style) with flux core it will work fine, It just costs $$ to replace diffusers.
3. If you really want to see a smooth weld see if you can find any 10 pound spools of dual sheild wire. It will be $$$. But for 1/4 or better it can not be beat. Esab makes a good line of dual sheild wires.
4. drive wheels, There is a long discussion of these as there are 3 major types, v groove, u groove and knurled. The best for flux core is a knurled drive roll. this will have little ridges in the wheel that will push the sire forward without crushing the outer casing of the wire. Your welder probably has a v shaped or a u shape, These are much better for solid wire but can crush the outer casing on flux core wire. This could be the feed issue you were having. Not sure but hope you enjoy the welder.
Dave
