Yup just read up, need argon gas, clean joint thoroughly with a SS wire brush, preheat then use high feed rate and ampage. Also 2 types of ally tig wire, one for sheet etc and one for cast stuff that are not interchangeable. http://www.mig-welding.co.uk/forum/threads/aluminium-mig-welding.615/
I'm planning on keeping my standard brake servo but the bodies foul it just so am working on angling them.
I currently run a remote servo which is fine but looks untidy.