I appreciate everyone's comments, but I'm still waiting for an answer to my question of how to dertermine what type of metal I have. I suppose I could shave off a few splinters of metal with a knife, and then try to burn it with a propane torch. If it glows very brightly while burning, then it probably is magnesium. Does anyone know of another way to test metals in order to determine what they are? I know with various grades of steel you could determine a lot about their makeup with a spark test by grinding them and seeing the color, brightness, and types of sparks that fly off. That basically shows how much carbon is in the steel. But what about testing Aluminum? Is there a simple test that can help you determine the type of Aluminum that you are about to weld?