Oh now ya tell me Steve,,, lol!! Thin to thin stuff would probably be easier. Having the base being the thicker stuff the thin wanted to retreat really fast. As soon as a decent puddle on thick base I just jammed a lot of filler rod in quick. Filled up well. And have to have it clamped down very close or it heat buckles. But it works. For me, I don't know what I'm doing so I don't know if something can't be done. Ignorance is a virtue!?!
Ran out of gas till Monday so I figured out what to make/bend.
My little 3 in 1 shear was having a hard time bending 16 gauge alum that wide, forgot heat is aluminums arch rival, a quick heat with the torch and she started bending. It's not tacked but just sitting in there till Monday.