Martinius, as an aluminum welder, I have to say I'm pretty suspicious. Anything that says it can go over oily areas or such sounds rather unlikely. With most things like this, it probably can't hurt to try, as long as the cost isn't too much, as the worst that will happen is it will fall off, then you can try welding it. I won't say it ain't possible, but I'd take their claims with a grain of salt. For brazing cast iron, a regular uncoated bronze rod with cast iron brazing flux works quite well applied with an acetylene torch. The flame ususally tends to heat the whole piece up gradually, allowing it to all expand and not crack. Post heating after the braze weld is made to let it cool a bit slower and evenly helps. As for aluminum, though...hard to beat cleaning it up, veeing it out, and tigging a new layer of aluminum back in. Bring it on over, I'll fix it for ya...