Well take a look at this and it will explain some stuff to you about aluminium welding. All welds have grain cracks. http://files.aws.org/wj/2006/12/wj200612/wj1206-14.pdf

 

Nice information. To sum up that article, USE ADEQUATE FILLER.

Fusion welds are a no-no.


Also, a spool gun is not needed at all. I tried aluminum welding last week on a HARBOR FREIGHT MIG with 0.030" wire. It worked fine. Not once did the wire birdnest, even before I realize that you mad wire speed and I would get burn-back. Even stuck at the tip, it would not birdnest.

However, the HF migs have a really shitty drive motor which feeds wire inconsistent, unlike Miller or Lincoln. They feed 10x more accurate.

 

Bingo.

Aluminum Wedling quite often is backwards. Burning through sometimes mean less wire, Build up sometimes mean more. It takes alot longer to dial it in then steel/SS

 

Just use aluminum stick. Get yourself a cheap SMAW welding machine and stick it. The welds are very nice looking, its easy to use and the welds hold up great. The only thing is if you want to weld vertical, you will have to weld up the joint. But just weld in the horizontal position. I'm pretty sure you need to weld with AC though to be able to break through the oxide layer on the surface of the aluminum. Also make sure that your use a stainless wire brush on the joint before you weld it. It just makes it easier to start welding and makes for a better finished product.