Castle^® Rubberized Undercoating is a tough, fast-drying, abrasion resistant coating recommended for areas that must be painted over. Rubberized Undercoating dries thoroughly, yet remains pliable enough not to crack when metal flexes. Surface can be painted in about 10 minutes. Several thin coats are more effective than one thick coat. Avoid application of materials closer than 12 to 14 inches to the entire exhaust system and catalytic converter.