For fumes, you need to wear a respirator ! A 3M twin-cartridge half-face mask with the correct filters will protect your lungs.


To your question, if you haven't welded aluminium before (that's how we spell it) with an AC tig, be aware that much higher current settings are needed cf. steel, as aluminium's heat conductivity is far higher. You can compensate to a degree with pre-heating the parts to be welded but that is going to be a pita with a bicycle frame I'm guessing.


If the material you are welding is around 4mm thick, I second the above suggestion of a 200 A machine. I think that will be enough, but not by much in my experience. It gets really expensive if you go to a much higher current machine though as you then start to need three phase power supplies and water-cooled torches and water coolers.


I see that you are in the US. Unless you have $$$ to spend on a good European machine (like CEA), or of course like some of those good American machines you have, I would recommend one of the best Chinese machines there is - the Unimig (forget the "mig" part, that's just the company's name, they make all types of electric welders) - apparently sold in North America under the Jasic and Razorweld brand names. They have a really nice 200 A ac/dc tig that is raved about over ("down") here.


That's Aussie dollar pricing so yours will be less. Also that's full retail so better deals are available. And finally, I just saw a message on Unimig's web-site that "they are launching in the US with local operations" so perhaps the Unimig brand is coming to the US in a much bigger way. Maybe you'll get some introductory deals ?


https://unimig.com.au/product/razor-...-ac-dc-welder/