Welcome to the forum, I've moved this to it's own thread.
In the top right corner of the page is a custom google search box, ask your question in there and you'll get plenty of info as it's been asked many times on here.
I have tried to do some Ally welding, I can get an arc but cannot get a weld pool, at some point it will flop through and I cannot even mix with a rod.
So far I cannot do it, never tried AC Ally though but I'm sure I will soon.
Thats the thing I cannot swap over the polarity and only have pure argon. For me its no bother though as end of next year I probably will get an AC Tig and for now have someone local who does my little bits and pieces.