Hey Really Appreciate the video. I have been welding on 3/4 aluminum and steady getting porosity. This is at high amps (250) 50/50 ar/he mix, 25-30 cfh, 3/32nd ceriated tung, 7/8 dia gas cup and gas lens, 65-70% balance on miller dynasty 100hz. I use acetone, then ss brush, preheat to 250° ( i also sometimes use acids to clean too) regardless of all of this I still get porosity. It drives me crazy man.... i wish I had a mentor that could stand in front of me with my welder and prove to me its even possible to 100% eliminate it on my application. (Light pole 3/8 wall, with a flange on bottom 3/4 6061, 4 gussets machined 1/4, ) all 1/4 fillet welds. I need a school or aomething....
David, porosity on aluminum is a constant fight. You are taking correct measures, but I fear that power might be your problem. My guess is that your welds have a greyish and dull appearance instead of being shiny. As you have learned, aluminum is a powerful conductor. It also has a strong affinity for hydrogen, especially in liquid phase. Much of the hydrogen will work its way out of the pool if it has a chance, but on sections as thick as you are working with, the aluminum freezes too fast to allow the hydrogen to escape. Does the porosity persist even if you are welding on thinner materials? If not, your amperage May be insufficient for the job.
