Thanks for answering my welding question about a month ago. Replaced the tip in my welder, ran about ten 4" beads. Didn't jam up once. Before it would jam up just about every time I pulled the trigger.

I also realized that I have .030" wire in my mig. I guess the preffered body shop wire is .025" Should I be using the smaller wire? What types of problems will I encounter using the .030" wire in body shop applications?

Thanks!

Mike

.030" solid wire carries more current which means for the same machine tap settings, the wire will yield deeper penetration. On sheetmetal that means much easier burn through and more warpage. Typical body shop wire is ER70S-6 solid .023" with a 75/25 gas mix.

10sec is right on. Before I fully understood how to use my MIG I used .030 for a number of years in the body shop everyday. So it isn't the end of the world, but .023 and the 75/25 gas as 10sec said is the way to go.

So, for the smaller wire, how would you reset your voltage for the same thickness sheetmetal? Smaller wire would mean more resistance, which would mean higher voltage settings, right?

Originally posted by MARTINSR:
10sec is right on. Before I fully understood how to use my MIG I used .030 for a number of years in the body shop everyday. So it isn't the end of the world, but .023 and the 75/25 gas as 10sec said is the way to go. A big ditto to that. I was using the .030 and a lot of times it would burn thru like I was using a plasma cutter smile.gif I just switched to the .023. Made a world of difference.

Originally posted by Randy Mosier:
So, for the smaller wire, how would you reset your voltage for the same thickness sheetmetal? Smaller wire would mean more resistance, which would mean higher voltage settings, right? A Mig welder is a constant voltage machine. You set the voltage & wire speed and the machine automatically varies the amperage to obtain consistant wire burn/melt off.

With a thinner wire, it melts at a lower temperature/amperage compared to the thicker wire. I can't really say how the machine settings would change between the two wires for the same metal. I usually go by the baseline setting under the cover and fine tune from there.

With thicker wire, it takes more "energy" or amerage to melt off in short circuit which gives it a deeper penetration.

Originally posted by 10secBu:
</font><blockquote>quote:</font><hr />Originally posted by Randy Mosier:
So, for the smaller wire, how would you reset your voltage for the same thickness sheetmetal? Smaller wire would mean more resistance, which would mean higher voltage settings, right? A Mig welder is a constant voltage machine. You set the voltage & wire speed and the machine automatically varies the amperage to obtain consistant wire burn/melt off.


With a thinner wire, it melts at a lower temperature/amperage compared to the thicker wire. I can't really say how the machine settings would change between the two wires for the same metal. I usually go by the baseline setting under the cover and fine tune from there.

With thicker wire, it takes more "energy" or amerage to melt off in short circuit which gives it a deeper penetration. </font>[/QUOTE]I realize what you're saying. Let me clear up the possible confusion. On my Miller mig welder, the voltage control is variable and adjusts like a rheostat which allows for minute adjustments. On Hobarts and Lincolns, the voltage setting is controlled by a four or five position switch. I understand that you probably would not have to switch voltage settings on one of those machines, since one click in either direction would be either too high or too low. Plus, each position on those machines represents a voltage range, so switching wire diameter would not make all that much difference. Like I said, on my machine, the voltage control is dialed up like a rheostat, which necessitates a little more fine tuning.

I just switched wire in my welder, and it's like the difference between day and night! I went from .030 to .025 and it's unbelievable how much easier it is to control on the thin sheetmetal. The smaller wire is unquestionably better for body work. The voltage setting remains pretty much the same, but the wire speed does have to be increased since the wire burns up faster. So, I sort of answered my own question.

Of course, I should have known this would be true for mig welding as it is for stick welding. For years I've known that when using a stick welder, you size your welding rods according the thickness of the material you're welding. The thinner the material, the smaller the rod. It's just plain common sense that the same principle would apply to wire feed mig welding. graemlins/clonk.gif graemlins/clonk.gif graemlins/clonk.gif