When processed with various other minerals, Cellulose powder can be used in the coating of consumable SMAW (arc) welding electrodes. When the arc is struck the cellulose coating acts as flux, vapourising at the same rate as the metal electrode melts, forming an inert gas shield around the molten metal puddle, which prevents oxidisation of the metal and helps maintain the arc. The Cellulose (no longer cellulose) then forms a crust, called a slag deposit, on the surface of the weld bead, which can be chipped away to reveal the bead itself.