Prep your tumbler first by removing the factory coating by either sanding or stripping. Plastic, ceramic, and glass must always be sanded. Apply at room temperature (68 to 78 degrees) and allow 2 hours of drying time between coats. Finish will self-level as it dries. Don't overwork your brush. Wet it and forget it. DO NOT USE HEAT GUNS to force drying. Grande Finale will harden up over a period of 5 to 30 days. You can gently use after 5 to 7 days.