Butt Welding Aluminum Pipes

[drifterific]

So I have had my PowerTig 250ex for a few weeks now and I can butt weld stainless and mild steel pipes together, but for the life of me I can not join two aluminum pipes together. The arc seems to want to wander between the two pipes. I am learning to weld aluminum pipes together for intercooler piping for my car. Any tips would be very helpful, I am going to go buy some flat plate from home depot and see if I can butt weld those together.

Im running about 65 amps with around 220 arc frequency and around 30% balance.

Oh also is my tungsten supposed to be balled? If I remember right Im using 2% lanthinated tungsten also.

Thank you guys for the help in advance.