Clean the fence post surfaces with 1 cup of trisodium phosphate mixed with 1 gallon water. Use a scrub brush to remove dirt and debris from the fence post, then hose off the residue. If the posts are new and clean, skip the TSP and simply hose off any surface dirt. Allow the posts to dry thoroughly before proceeding.
Stir the paint with a wooden stir stick until evenly mixed.
Dip a bristle paintbrush into the paint so the bristles are three-quarters covered and let the excess drip back into the bucket. Apply the paint to the surface until completely covered.
Leave the paint to cure for 24 hours in areas of low humidity or up to 48 hours in high humidity. Apply a second coat. If the surface was new, you only need to apply one coat of Black Beauty.