One of the most difficult alloys to weld is the aluminum for it should be cleaned from exterior before welding. Spaced out from standard techniques such as gas, plasma, and others: aluminum welding techniques include tig and mig welding!
For welding thicker aluminum work pieces at a faster rate and to achieve long and continuous welds mig welding technique is best. On the other hand the tig technique is used for good facade finishes. Generally it includes pipe welding and casting repairs.
The best think to concentrate is on the wire feed welder, the wire should be loaded properly into the machine. As there are loads of possibilities for it to get disrupted in the middle it is a must to clean the aluminum thoroughly to avoid defects.