I have always been told that basically the tungsten should match the gauge of metal to be welded I have always struggled with thin tungstens e.g. 1mmm for body panels .. 20 gauge steel I am achieving better results with 2 even 3mm tungsten maybe because I can sharpen them more efficiently. Sadly the issue has diverted me back to mig welding but I certainly would like to perfect a technique to enable a better outer facing finish weld for example external wheel arch panels. Am i doing something wrong? I know there are many variables even down to individual machine settings including flow rates etc. I do keep coming back to electrode size does anyone have any views?