[rich-allen]

If your not getting the aluminum to melt then 95% chance you don't have the heat high enough.
The heat generated with aluminum welding is why they use water to cool the torch. Crank up your power to 180 and see if that helps.

I know of guys that actually preheat the thicker pieces of aluminum to 400 degrees when using a low output welder.
A basic rod for aluminum is 4043, when welding material 1/8", a 1/16 dia. rod is optimal.

Your tungsten should have a ball on the end. The best method is to reverse your polarity and strike an arc on some mild steel. Switch your machine back to AC and your good to go. If your tungsten touches any part of the filler rod or weld pool it becomes contaminated. Break off the contaminated part of the tungsten and ball the tip again.

If you were having problem like the material was blowing off when you struck an arc, that would a tribute to not having the proper tungsten.