MIG/GMAW

How do i MIG/GMAW weld my cracked thin aluminum irrigation pipes?

During the winter sometimes there is water left in them and they freeze and crack open. The aluminum is so thin that when i try to mig weld it, it just eats right through it. I can adjust the settings such that it doesnt but the metal is just dripping slowly onto the pipe. This is a very sloppy way to do it, i know there must be a better way.
I use .30 aluminum wire fed through the spool gun, as well as using 100% argon. I also keep the end of the wire clipped off when starting the pool, but have the same trouble listed above