Big paint companies like House of Kolor offer an assortment of flake sizes and colors that are actually made of plastic, not metal. There are grades from extrafine to what people like to call "speed boat" to stuff so thick that you just blow it on from a pile in your hand. Santini prefers to use silver instead of colored flake. The reason is that if you cut through to the colored flake while finish-sanding, you will saw off any corners that might be poking through the clear. The result will be silver chips that you will be able to see.