A coating method is disclosed including disposing a coating composition into a fluidly communicating space defined by an internal surface of an article. The fluidly communicating space includes at least one aperture, which is sealed, forming an enclosed space. The internal surface and the coating composition are heated under autogenous pressure, coating the internal surface with the coating composition. The at least one aperture is unsealed, re-forming the fluidly communicating space. Another coating method is disclosed in which the coating composition is disposed into a reservoir which is connected in fluid communication with the enclosed space prior to heating under autogenous pressure, coating the internal surface with the coating composition. Yet another coating method is disclosed in which the coating composition and the article are disposed in a vessel, which is sealed, forming the enclosed space prior to heating under autogenous pressure, coating the internal surface with the coating composition.