Development of Fastener Countersink Corrosion Protection Seals

摘要

The objects of the program were to modify coating materials for use with specialized application equipment, to study application techniques applicable to production practices and to develop a color stable (non-yellowing) material suitable for this use. All objectives were oriented toward development of an elastomeric sealant system designed for use in sealing fastener-head countersinks in highly loaded aircraft skins that are susceptible to exfoliation corrosion. Materials were formulated that could be smoothly deposited on vertical surfaces to thicknesses of 5 to 7 mils per pass utilizing vapor-carrier type spray equipment; other materials formulated for use in conventional application equipment were easily applied to an aesthetically smooth finish with a minimum loss of coating build per pass. These coatings were manufactured in commercial facilites and test results obtained from these materials correlated with laboratory experimental data. Materials and application techniques developed as a result of this program have significantly reduced the costs of applying fastener-countersink seals to production aircraft. (Author)