Perk up your curb appeal with a garage door redo. Metal garage doors are sturdy and don't require a lot of maintenance, but they do need a good coat of paint from time to time -- just to protect them from the elements. Exposed bare metal will eventually rust, which weakens the structure of your garage door. If your doors are chipping and peeling, give them a simple facelift using nothing more than paint and primer.
Use a hose with a spray attachment nozzle to spray off your metal garage doors. This will power away dirt and debris.
Scrub the garage door vigorously using a strong detergent and an abrasive scouring sponge. Use circular motions when scrubbing the door. The detergent and scrubbing action removes dirt and rust and roughens the surface so that it will hold paint better. Any strong detergent is sufficient. You can purchase a strong detergent at a hardware store.
Rinse the detergent off the garage door using a hose with a spray attachment nozzle. Allow the door to air dry.
Stir and pour the exterior primer into the spray gun. Acrylic paint is a good choice for garage doors because the paint is flexible and will bend instead of chip during garage door movement. This is important because garage doors move often during normal use.
Apply the primer to the garage door. Spray a thin coat of paint using long strokes. Allow the base coat to dry for 2 to 24 hours, depending on the brand of paint. Look at the paint manufacturer documentation to find the suggested drying time.
Prepare the color coat. Rinse out the spray gun canister to remove the primer. Dry the canister. Open the acrylic color paint. Thoroughly stir the paint with a long stick, and pour the paint into the spray gun.
Paint the color coat on the garage door using the spray gun. Only apply a thin coat of paint. The paint should be fully dry in 24 hours. If desired, paint a second coat of paint on the garage door.