This coarse lapping powder can be used to lap the backs of tools or coarse grit waterstones.
Due to it's extreme harshness, we recommend it only be used in extreme cases of abuse or neglect.
The heavy scratch pattern left by this silicone carbide powder can be hard to manage. We would recommend it be worked as long as possible to refine the scratch pattern, and then followed by the medium grade powder. We use this with our mild steel lapping plate, though it greatly reduces the lifespan of the plate. Only apply this powder to one side of the plate, and dedicate the remaining side to fine lapping.
Shapton recommends this powder be used with it's own brand of lapping plate to flatten coarse water stones, though we have not used it in this capacity yet.