Products / RAP

RAP is a milky white, waterborne rust conditioner and primer that Topps supplies to prepare rusty metal roofs for coating with its water-based Topps Seal WB. Its technical data sheet says it converts powdery rust into a more stable oxide bound in a vinyl barrier that dries to become the primer coat, applied by pump-up sprayer, roofing brush or roller after the roof is power washed. The sheet lists zero VOC, 10 percent minimum solids, a 1-hour dry-to-touch time at 77 degrees F and coverage of 200 square feet per gallon on rusty areas only, and the maker's catalog says it is designed for water-based coatings only.