Mold-in-Place Coatings

Many airborne vehicles require thick polymeric coatings on complex, concave and convex surfaces, which may be metallic, composite, or ceramic. The common method for applying these coatings involves spraying many individual layers, and allowing solvent flash and drying between each layer. A coating which is built up to 0.250” thickness, may require more than 100 layers of sprayed on coatings. This approach requires long staging times in a spray booth, issues with solvent emissions and abatement, detailed robotic programming to follow a complex curvature, and may still require grinding, sanding, and thickness measurement at the end to assure a uniform coating has been applied. Our proposed innovation allows for the injection molding of a thick coating in a single step directly on the aircraft. A tool which is machined to mate to the curvature of the substrate surface, providing a fixed spacing, can be mechanically or vacuum attached to the surface, creating an injection molding cavity. A thermosetting polymeric system can be mixed and injection molded into the cavity as a 100% solids formulation, thus eliminating all solvents. Once cured, the tool is removed manually or mechanically, depending on size, leaving the molded coating on the surface.