hey guys I asked our welder what he thought and you dont need to use pure argon its way more expensive goto liquid aire and get some 25% argon 75% CO2 works just fine for mig pure argon is generaly for stainless and aluminum TIG welding! i forget what the actual mix's are called but they will know liquid air pretty good. And use .020 or .025 for body panels you'll get the best result and keap the heat pretty low I dont know the settings depends on the welder Just get some scrap and practice!!