A good couple of pounds, the main reason is because most of the scrap i melt is extrusion and tubing i add copper to the mix. It makes it better for cutting but as consequence adds to the corrosive mix. A good tip for better quality ali, save old wheels, hard drives or similar. Thanks to a good friend i manage to own a piece of farri (part of wheel), very nice magnesium. be careful though skool boy science will tell you what happens if not done with care