FLEX SEAL Family of Products FLEX GLUE Clear Rubberized Waterproof Adhesive 4 oz, Pack of 6, Packaging may vary. FLEX GLUE is an easy-to-use, super strong, rubberized, waterproof glue that instantly bonds, seals and repairs virtually everything. This adhesives instant grab technology holds objects in place and, in most cases, eliminates the need for braces. It cures in 24-48 hours and reaches maximum strength in 7 days. No need for screws or nails, its perfect for all types of repairs.