You can repair flaking and peeling paint on your microwave if you commit yourself to thorough surface prep. If you attempt to paint directly over failing paint, the new finish will peel. Eliminate flaking paint and smooth the surface to promote an attractive, lasting finish. Use the right paint, formulated for durability, and apply it the right way, or expect to see flaws in the finish coat.
Clean the microwave with a water-based cleanser, using a sponge. Rinse with microwave with wet rags and dry it with towels.
Use a plastic putty knife to scrape flaking paint from the microwave. Smooth rough sections of chipping paint, using sandpaper.
Use masking paper and painter's tape to cover those areas of the microwave you'd like to remain unpainted. Place the microwave on a dust sheet in a ventilated area.
Coat the damaged area with acrylic latex spray primer. Use a Galvanized metal etching spray primer on metallic microwaves. Maintain an 8-inch distance between the microwave and spray nozzle as you apply. Wait three hours for the primer to dry.
Apply acrylic spray enamel or appliance epoxy spray paint to the to the primed portion of the microwave. Maintain an 8-inch distance between the microwave and spray nozzle as you apply. Wait three hours for the new finish to dry.
Don't use latex paint on a microwave, as it will not remain durable. Do not paint directly over unprimed areas of the microwave, or the finish may chip and peel. Be sure to maintain an 8-inch distance between the microwave and spray nozzle, or you may have runs and sagging.