Bare drywall, where the taped and mudded seams and fastener holes are still exposed, requires priming before painting. Drywall soaks up more than its share of paint. The 1^st coat consists of applying the mud-saturated tape to all of the joints and corner beads and filling screw or nail holes for the first time. Begin with the butt joints first, then the horizontal tapered joints, then the angles, and finally, the corner beads. A coat of drywall mud takes about 24 hours to dry when the temperature is about 70°F and humidity at 70% or lower. The curing time varies depending on the thickness of the joint compound, depth of application, humidity levels, and temperature. Always allow the mud to dry before applying a new coat. After the first coat has dried completely, you will need to sand and apply two more coats to the fasteners, sanding between each coat.