Thanks for the replies. Very informative and helpful.

I am getting a lot of pepper on the weld pool when I start a fillet weld on aluminum. I wipe down both pieces of the T joint with acetone before I start. After about a half inch or so of travel the welding pool becomes clear and shiny. I am using a no. 8 gas lens, 20 CFH pure argon, 3/32 lanthanated...