You can paint the inside of a dryer drum as long as you choose the proper coating. Before you begin, consider that many dryer drums are composed of bare galvanised metal. Paint will not adhere to bare metallic surfaces unless they are conditioned with a special acidic primer. Once the drum is properly prepared, it will accept its new finish. Select a special heat-resistant appliance enamel, or the finish will not remain durable in the long run.
Unplug the dryer and ensure that it is cool.
Smooth old, chipping enamel by sanding it with 180-grit sandpaper.
Remove enamel chips and dust from the dryer, using sticky tackcloths.
Cover areas you do not want painted with masking paper and professional painter's tape.
Coat bare metal dryer drums with galvanised metal etching spray primer. Maintain an 8-inch distance between the drum and the spray nozzle as you apply. Leave the dryer door open and wait six hours for the etching primer to dry. Skip this step if the dryer drum is already painted.
Coat the dryer drum with heat-resistant appliance enamel spray paint. Maintain an 8-inch distance between the drum and the spray nozzle as you apply. Leave the dryer door open and wait a full day before using the dryer.
Put on a respirator before applying the primer and paint.
Do not paint directly over bare metal dryer drums, or the finish will peel. Do not use ordinary paints on a dryer drum, as they will not remain durable. Do not use ordinary primers on bare metal, or the final finish will chip.