When I bought the used SP125 Plus welder it came with a roll of .035"
70S6 wire. I practiced with this wire and got good welds. Then Ernie says that .023" 70S6 is the largest mig wire that should be run with this machine. I bought some .023" wire and started welding. I was able to get very good welds but I felt that I had just as much success with the .035" wire. Then yesterday I loaded the .035 wire in and made some welds. I noticed that the welds were too proud and this probably meant that penetration was poor. I looked at my previous practice pieces and those welds were fine. After fiddling with adjustments it became clear to me that in order to get good welds with good penetration running .035" 70S6 the wire speed had to be real slow or the plate needed to be pre-heated. All the welds I had done with .035" wire were not the same. The really good practice welds were ones that had been run after several beads had been run and the plate was hot. In the future, if I have to use .035" mig wire on this little machine I will first pre-heat the part. It runs .030" 4043 aluminum wire fine but it sure is easy to burn through thin stuff with aluminum. There is a fine line between too low and too high voltage. Just a tiny adjustment makes a big difference in the puddle. I'm now looking for a used gun and cable assembly so I can have one for aluminum and one for steel. Changing liners is tough but just unplugging the cable would is easy. ERS- posted
17 years ago