The flakes are usually aluminum, and the metal has more mass than the finish it's mixed in. You have to apply a LOT of it, from slightly farther away from the surface to keep it from striping. It just scatters like crazy. Most places (or persons, in my case) who shoot metal flake or pearl devote spray guns to shoot only those materials, to keep from contaminating the guns and cups used for clear and opaque finishes. You can keep your spraying area as clean as possible, but having solid materials in your finishes complicate things by a wide margin. I used to shoot real glass & mirror flake and that **** creates even more problems. It will HURT YOU if you aren't careful. Personal protection equipment is a must, but it only goes so far. Clean up duties are in-depth and absolutely essential. Which is another reason why it costs more...