Dura-Prime is the best water-based exterior primer to stop tannin and rust bleed problems. Dura-Prime comes in a clear base and helps new and weathered projects last up to 20 years. Dura-Prime is a bonding primer and is for new, peeling or weathered surfaces: wood, metals & masonry. Blocks rust and tannin bleed. The best choice for solving the most challenging paint projects.