Putties are compounds that repair surface damage and prevent leaks by filling cracks, holes, or crevices. They are available in different formulas for a range of permanent repairs and emergency repairs, from sealing gaps in underwater applications to stopping leaks in gas tanks, pipes, ruptured radiators, and pools. Putties are also available for repairing wood and autobody surfaces. Two-part epoxy putties begin to set after mixing and are capable of reaching a full cure within minutes.