Play sand is the worst thing you can use both for your health (especially) and the metal. Anything with silica in it is bad. Google silicosis. Black beauty/Black diamond is ok but better on thicker stuff. It is silica free though. Crushed glass costs the same as black diamond and is a much better choice. Northern Tool has it as does Tractor Supply.I use play sand in bags from Ace Hardware, poured thru a screen. Idk about black diamond it sounds pretty aggressive but with pressure down may be ok?