Welding Tips and Tricks

This video is very useful, for quickly identifying the type of aluminum filler rod.
http://www.youtube.com/watch?v=92AGE3gp9m8
http://www.youtube.com/watch?v=sPUXcfsrEtU

How to prevent porosity when welding aluminum?
http://www.youtube.com/watch?v=Yu3BtdERmFM

The effects of AC frequency on your welds?
http://www.youtube.com/watch?v=ftL2NP3TCok

The effects of AC balance on your welds?
http://www.youtube.com/watch?v=u-daLs9Q7ac

Thanks for the videos mate!
There were some very good tips that were brought up and explained clearly.

-Markus-