SMR-15 is a two-part polyester putty for repairing minor bodywork imperfections. It has excellent leveling properties and is easy to sand. SMR-15 can be applied directly to bare steel, galvanized steel, aluminum, and cured paint surfaces after sanding with various grit papers depending on the substrate. The putty is mixed at a 100:2 ratio of putty to hardener by weight and applied in thin layers to allow surface imperfections to flow out during curing. SMR-15 becomes sandable after 20 minutes.