Abstract: A lightning-protected conductive composite fuel tank includes a conductive material arrayed on an outer surface to at least partially cover a fastener centerline. Through holes extend along the fastener centerline through the conductive material and the underlying fuel tank shell. These through holes are countersunk into the fuel tank shell to a depth such that a fastener in a through hole will avoid electrical continuity or communication with the conductive material on the fuel tank outer surface. The gap in the countersunk through holes, between the fastener heads and the coextensive outer surface of the fuel tank, is filled with a dielectric or nonconductive material.

Abstract: Apparatus and process for continuous surface preparation of metal materials. The metal material is grit blasted with a mixture of fine particles of aluminum oxide in air and water. The metal material is rinsed with water to remove the grit. The metal material is subjected to a caustic solution of sodium hydroxide and then rinsed with water to remove the caustic solution of sodium hydroxide. A sol-gel coating is applied to the metal material and the water portion of the sol-gel coating is evaporated. A liquid adhesive coating is applied to the sol-gel coating on the metal material and the solvent portion of the adhesive coating is evaporated.

Abstract: A method of treating a metal material to increase the metal's ability to adhere to other objects is provided. The metal material is prepared to receive a sol-gel solution coating. A sol-gel solution is prepared and the sol-gel solution is applied to the metal material. Subsequently, an epoxy-based adhesive coating is applied over the sol-gel solution, thereby creating an adhesive layer on the metal material.