The interaction between its elements and the environment means that stainless-steel doesn't rust. This is the optimum choice in a sink where a waste fitting will continually come in contact with water. Use some silicone sealant between the stainless-steel waste flange and the glaze to stop the water from draining under the flange. Clean the surface of both the stopper and your fireclay sink before instillation with Mineral Turpentine to ensure the silicone adhere successfully. Then once the waste fitting is tightened, use the same cloth to clean up any excess silicone before it dries.