Put on a pair of sturdy work gloves. Wash the cap with an all-purpose household cleaner and rags. Let the cap dry completely.
Set the cap on a pile of newspapers in a well-ventilated area, preferably outdoors. Put on safety goggles and a dust mask. Shake the spray primer for at least 30 seconds to 1 minute.
Hold the paint can at least 10 to 12 inches away from the cap. Apply a thin layer of primer over the entire cap using even back and forth motions. The primer prevents the paint from flaking off the unfinished steel.
Allow the primer to dry for at least 24 hours before applying the metal spray paint in the same fashion as the primer. Let the first coat of spray to dry for another 24 hours, then apply a second coat.
Let the final coat cure for 24 hours, then install the chimney cap according to the package directions. The majority of standard caps are mounted inside on the chimney’s top with adjustable screws.