Sorry for the lag
But yet another vote for L-56; and I quote:
Matt: There are many good wires available- I happen to use LINCOLN L-56 for general Mild Steel applications. I suggest using a C-25 [75% Argon, 25% CO2] Shielding Gas for short-circuit MIG/GMAW welding. With this wire & gas combination, spatter will be minimal if you use proper Volt & IPM [wire speed] settings. Straight Carbon Dioxide gives less acceptable results, producing more spatter & wasted wire; the welding arc in CO2 is also somewhat less stable, with a tendency to promote "cold-lap" , and has a less attractive bead appearance. If for some reason you were to want to use the "Spray-arc" mode of wire transfer, you would need to use a gas with at least 87% Argon. I use O-5 [95% Argon, 5% Oxygen] for Spray-arc.
Another gas choice for .035 short-circuit welding on mild steel is a product called Stargon [90% Argon, 8% CO2, 2% Oxygen], it has the effect of inputting more heat to the weld zone.
I actually prefer it to C-25.
Ray
Have fun now that you need to try another gas too :flipoff2: