I had a unique problem that required a unique solution. I needed to attach aluminum cornices to a concrete ceiling in 3 different rooms. I didn't want to mess with cranes and hold a hammer drill overhead for hours drilling a concrete/rebar deck. My solution was glue/epoxy. To prepare, I sanded the concrete and aluminum and cleaned them with acetone and a brush. Dry the excess acetone with a hair dryer. I tested several different adhesives that claimed to stick to both surfaces, but none of them were strong enough to be sure. On a whim I tested this product, although it wasn't made specifically for metal I was blown away by how well it held up. These cornices don't move. It sands very well so I can sand off the excess epoxy to get the valence flush with the rail.