On the subject of welding aluminum, welding aluminum with DC takes helium which has gotten expensive in recent years and you have to use reverse polarity DC to weld aluminum.
Problem with reverse polarity tig is it puts the vast majority of heat into the welding electrode. The welding electrode gets something like 8 times as much heat running in reverse polarity.
When welding straight polarity the vast majority of the heat goes into the work (80% to 90%).
Mostly balanced organic AC power will not heat up the electrode as much as reverse polarity DC. The electrode might see around 4x the heat as compared to running it straight polarity.
The expensive AC machines can create 400Hz AC power that has 90% of the power on the straight polarity side and 10% on the reverse polarity side.
You have to have at least some reverse polarity to deoxidize the aluminum.
In the past, with welding aluminum you had a choice of using a cheap DC machine with over sized water cooled torch and more pricy helium, or a super expensive AC machine and cheaper argon gas.
In recent years the price of the expensive high frequency AC machines has come way down (but they are still expensive, a few thousand dollars for a good one), the price of helium has gone way up, if you can even get it so almost everyone has gone with more advanced high frequency AC machines that can weld aluminum with cheap plentiful argon.
Now what I cant find any info on is if balanced 60Hz needs argon or helium or a blend, or if it will even work. Since you can weld aluminum with DC+ and helium I don't see why I couldn't make 60Hz AC work unless there is some kind of funky magnetic, hysteresis, eddy current losses going on.
I have 1/8 inch wide Zirconium oxide doped tungsten electrodes that are supposed to be toughest most heat resistant electrodes you can get. Some time soon I will plug the leads into AC put one of those electrodes in my torch put it to aluminum and see what happens.
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