Metal Doors Need Paint PreppingSeptember 19th 2014
Q: Our House has a metal exterior door that needs to be refinished. What is the best way to prepare the door for painting and what type of paint do you suggest?
A: Exterior metal doors are exposed to all kinds of weather conditions: hot, cold, wet and/or windy. These extremes cause the metal to expand and contract considerably, requiring a flexible type of finish.
Proper preparation of the door before painting is important. Remove the door and put up a temporary panel while you proceed with the finishing.
Remove all the hardware from the door, including the hinges. Sand the door lightly with 300/400 grit wet/dry sandpaper to break down and remove any sheen the existing finish may have. After sanding, wash the door with a non-phosphate cleaner and rinse well with clean water. When the door is cool, apply two coats of exterior acrylic urethane with a synthetic bristle brush. Do the edges first and then one side at a time. Allow each side approximately 10 to 12 hours drying time before doing the second side. You may wish to re-hang the door between coats, as 48 hours is required for the full curing process.
For a truly satisfactory result, you will need a dust-free environment and preferably temperatures of 15 to 20 C (60 to 70 F).
If your door has a glass insert, paint the plastic frame around the glass with an exterior acrylic latex paint using a nylon synthetic brush.