Hack, I just had my header tank built yesterday. It seemed pretty easy. Find someone who can work with aluminum. They will need either a TIG or DC wire welder (with 100% argon shielding gas and aluminum wire) and they can weld it for you. The TIG will seal it better, but the wire welder works. A guy wire welded mine for me and we have a couple of tiny leaks that we couldn't get, but I will be using a sealant to coat the inside of the tank with. He only charged me $30 to do it, and he didn't have a TIG so I'm not complaining.
If everything goes right, I might have it running by this weekend!
If everything goes right, I might have it running by this weekend!