thats not average tech advice thes correct advice to weld alli all you need is a 15amp socket and a dc tig, you can ONLY tig with dc other wise its an ac current, think about it dc, direct current, ac alternating current, you can weld if your power fluctuates, you can plug it into an ac socket but you're machine all be it not a dc converter will have pre flow, post flow and high frequency control so it is just the same as dc, a constant direct current coing out of the tip, have a look at alli welding basics mate, you will be best of welding it with a dc machine for a bike frame, learn your shit and think about it
http://www.weldcraft.com/2006/11/basics-for-tig-welding-aluminum/