To make a door look brand new, even an exterior steel one, sometimes just means putting on a new coat of paint. Making it look a new color can help it look updated and matched to the rest of home renovation without spending lots of money on a new door.
As with a fiberglass door, clean it first with a wet sponge filed with acetone or other mineral solvents and let it dry. Be sure to cover the glass or other window accents on the door before starting the project. Next, sand away the old paint if it’s an old metal door so the new coat will adhere better. Do not use palm sandpaper. You can skip this step if this is a new metal door.
Afterwards, apply an oil-based primer using a foam roller and a foam brush for any raised or depressed paneling in the door. With the same foam materials, apply the primer to the sides starting at the center and ending with the sides. Let it dry overnight. When dry, sand it lightly with fine sandpaper. Then apply a second coat. Let the second coat dry for six to eight hours. Apply two more coats, one for color consistency and another to get any blemishes or inconsistencies across the door.
Oil-based finish paint is not recommended because it tends to yellow with time and it is more prone to mildew, a factor in damp climates. Make sure the paint is dry before your reattach the door to the hardware and the entryway. It’s recommended that you wait a day.
Do not use a dark color if the door is exposed to direct sunlight. This will increase the heat penetration. Because the interior panel will be cooler than the exterior panel, the two will expand at different rates, which can cause the door to buckle or bow.