A metal storm door is purchased for protection against the elements, rather than beauty. As such, it is not always the most pleasant fixture around your home, but that can be rectified by using metal door paint. You can turn your metal storm door from an eyesore to a winner with no more than a weekend's work.
Step 1 - Make Preparations
Remove the door from its hinges using a screwdriver and lay it on top of the drop cloth. Take off the door knob as well, along with the deadbolt and any other hardware you might have. It's also a good idea to remove the hinges completely. Set all of these pieces and their screws aside in plastic bags so you don't have to worry about losing parts.
Use masking tape to cover any area of the door where you don't want metal paint to get into. This would include inside the door knob hole as well as the deadbolt. Any paint that gets in these areas could cause the fixtures to not properly fit when you're finished.
TIP: If you're not sure you can remove and carry the storm door without damaging it, get a friend to help you remove it.
Step 2 - Clean the Surface
Make sure the area you plan to paint in is well-ventilated, as this will help for cleaning as well. Start by inspecting the door for rust. If you happen to find some, you can get rid of it by scrubbing with a wire brush. Remove as much of it as you can, to a degree where it will at least be flat and smooth with the rest of the door. Then, wipe the metal down with a rag, followed by a tack cloth to remove the rust filings. If you wish to paint the entire door, repeat on the other side.
Mix the oil-free liquid soap in a bucket with hot water. Submerge a rag in it and give the entire door a once over. Take a clean rag to the surface when you're finished to get it dry.
Step 3 - Paint
WARNING: Make sure once again that the work area is well-ventilated (especially if you have to wait a day or more between cleaning and painting the surface) and put on a respirator mask and safety glasses before you start applying paint.
Now that the door is cleaned and prepped, you can apply the primer metal paint. Metal is often difficult to paint due to the fact that it's very smooth, so it's crucial that you create a texture for it to adhere to. Use sandpaper to scuff up the metal in all areas where you plan to paint. Wipe off the metal filings with a rag, followed by a tack cloth.
Pour the metal primer into a paint tray, and dip the roller into it, removing excess paint as needed. Roll it onto the surface of the door as evenly as possible; watch out for pools of primer, streaks, and other mishaps, so you can fix them before the paint can dry. Touch up any hard-to-reach areas with a flat paintbrush as well. Then, wait for the primer to dry flipping the door to paint the other side or adding a top coat.
Apply the top coat to the metal storm door in the same manner as the primer. Always make sure to follow packing instructions for dry times before applying any additional coats of paint. Once you're finished completely, give the door at least a full day to dry before you rehang it. Drying can take longer if your weather is particularly humid, so be careful.