[JThiessen]

Brian, I tried that stuff that you linked to. I am experienced in TIG and MIG welding, so hopefully I can lend some insight.
True welding involved creating a molten pool in both parts that you are trying to weld, with the addition of a filler material. The product referenced does not do that. It relies on surface adhesion. So basically you are "gluing" your parts together. You have to get your parts very clean (and use a stainless steel brush - which I still havent figured the function of yet). You also need to make sure you are doing the correct materials.
I made my battery trays and nerf bars using this product on my E-Revo. They held up for about a year, but then I had to "make them right" using a mig (thanks to my Brother in Law). You will not get a professional looking weld from it, nor will it hold as well as a mig or tig welded part.
A mig will easily weld any of the aluminum that we RC'ers will encounter.