Bondo Body Filler Stage 3 in minutes and will accept as many reasonably applied applications as required to fill holes and deep scratches or dents. Once it has completely hardened - normally in 25 minutes or less - Bondo Body Filler can be sanded using various grits to achieve as smooth a finish as required. In addition to its uses in repairs of typical vehicle surfaces, the filler is also suitable for repairing other surfaces including wood, steel, aluminum, fiberglass and concrete. Bondo Body Filler products include directions that help you easily create just the right mix for your auto repair job and allow for same-day repairs.