Why Deck Railing Paint Fails | S&L Spindles Aug 29, 2015 . (If only the surface of the wood is wet, then only one sunny day is usually needed for drying prior to painting. If the wood is . Painting wood deck spindles. Deck railing . However, at least 2 hours are needed for the fresh paint to dry before weather conditions cool to the point where dew forms. If blistering..