Abstract: A method and product for repairing a sound attenuation structure for aircraft jet engine noise that includes a central honeycomb core having an imperforate facing sheet adhesively bonded thereto and a perforated facing sheet adhesively bonded to the opposing surface of the core with a woven wire cloth media adhesively bonded to the outer surface of the perforated sheet. The wire cloth is subject to deterioration and disbonding in service use. The method provides for the removal of the deteriorated wire cloth that has disbanded or deteriorated and, after cleaning of the perforated sheet and the associated honeycomb core area, and priming of the cleaned area of the perforated sheet replacement with a polymer film that is precoated with a pressure sensitive adhesive so that the film may be easily applied to the exposed perforated sheet area in place of the removed wire cloth.

Abstract: A method and product for repairing sound attenuation structure for aircraft jet engine noise that includes a central honeycomb core having an imperforate facing sheet adhesively bonded thereto and a perforated facing sheet adhesively bonded to the opposing surface of the core with a woven wire cloth media adhesively bonded to the outer surface of the perforated sheet. The wire cloth is subject to deterioration and disbonding in service use. The method provides for the removal of the deteriorated wire cloth that has disbonded or deteriorated and, after cleaning of the perforated sheet and the associated honeycomb core area, and priming of the cleaned area of the perforated sheet replacement with a polymer film that is precoated with a pressure sensitive adhesive so that the film may be easily applied to the exposed perforated sheet area in place of the removed wire cloth.

Abstract: An improved method of anodizing aluminum which produces an oxide surface receptive to the formation of strong and durable bonds with epoxy adhesives and coatings with underlying bulk properties providing dissimilar metal separation and basic corrosion protection. The invention provides a two step electrolytic process which includes, firstly, anodizing the aluminum with a phosphoric acid solution and then, secondly, further anodizing the aluminum with a sulfuric and boric acid solution. A product is provided that has a final coating having two anodized regions. The first outer region produced by the phosphoric acid solution is about 3000 angstroms thick and is characterized by open pores which is particularly well suited for the establishment of stable, strong and durable bonds with epoxy primers and adhesives. The second base region produced by the sulfuric/boric acid solution provides a thick, tough, corrosion resistant region about 15,000 angstroms thick.