It has to do with the filler material & the flow characteristics of the metals that you are welding. I ran into the same problem when I was filling my bottles up. everyone would tell me what I was supposed to use, but nobody would tell me why...........
You will also find that some wire will not weld well in certain directions & possitions. for example, if you use the normal ER70S-6 with the Arg/CO2 gas, it will not weld real well vertically & overhead, but it welds REAL nice when its on the bench nice & flat. the E71T-11 (no gas) will weld pretty nice vert & overhead, but its messy (lots of splatter). Im looking for a good wire that will weld vertical & overhead with the Arg/CO2 mix. I found 71M on the Miller site that is supposed to work well in "off possitions" & can use the same Arg/CO2, but they recommend 100% CO2. I have not had a chance to look around to see if anyone has any of that here.
If you want to see what happens when you use the "wrong gas" with different wires, grab your buddies 100% argon & fire it up with the ER70S-6 & you will see how ugly the welds come out. the "flow" of the puddle is just not right.
Bob
