Cleaning and Chemical Treatment of Aircraft Surfaces to Provide Optimum Cleaning Properties

摘要

Final results are presented of a program to develop improved methods of cleaning aircraft surfaces prior to painting. The first objective of the program was met by the development of a simple and accurate method for determining the degree of cleanliness of surfaces. It consists, essentially, of placing 5-microliter drops of distilled water on the test surface, measuring the drop diameter and converting the drop diameter to a quantitative value of surface energy. Nine cleaning procedures were evaluated by means of radioisotope, surface energy, hydrogen embrittlement, and coating adhesion tests. The best two procedures were applied to a C-130 at Lockheed-Georgia and to a P-3 aircraft at Lockheed-California before the final epoxy-polyamide paint system was applied. Five hand-peelable and five alkaline-removable coatings were evaluated for their ability to protect clean surfaces from contamination. The strippable coatings which gave the best results in laboratory tests were applied to P-3 fuselage panels. Hand-strippable coating No. 14 provided good protection for the panels during chemical cleaning and during drilling, countersinking, and riveting operations. Chemically strippable coating No. 11 provided good protection for the panels during the drilling, countersinking, and riveting steps. (Author)