Flex-seal is probably the most versatile head cement available to the fly tyer. It is a rubber based compound that is clear, deep penetrating, and quick drying. When dry it produces an extremely tough “rubber like” finish. A good way to describe Flex-Seal is to say it is a sealant, adhesive, and head cement all wrapped up into one product.
Many fly tyers use Flex-Seal to increase the durability of their flies and deer hair bass bugs. When applied to feathers and deer hair the fibers remain flexible (“rubbery”), retain less water, and do not become brittle. It is important when using it for this application to thin the product with Flex-Seal Thinner and apply it sparingly to the fly.
Our favorite use for Flex-Seal is as an “under body” glue for delicate materials such as peacock or ostrich herl. Apply a small amount to the hook shank before overwrapping these materials. Likewise a light coating over the hook shank before applying dubbing creates the toughest fly on the planet!