A method of forming an electric circuit on a substrate

An electrical circuit is formed on the surface of a substrate 16, e.g. a vehicle door trim, by first applying a film 50, then removing portions of the film to expose the substrate along desired circuit paths 60 and then applying conductive material 10 to form the circuit. The film 50 may be polymeric with a first adhesive layer 58 for attaching to the substrate and an adhesion resistant layer 56 to reject the conductive material when it is applied as spray 70 of molten metal particles. Alternatively metallic powder in hot air may be attracted electrostatically. The circuit paths 60 may be cut by a laser or may be formed by blades simultaneously with a vacuum forming step for shaping the substrate.