Abstract: A stainless steel mandrel (10) is etched with a negative pattern (16) of an electrical circuit that is to be made with the mandrel and then covered with Teflon (20) which is subsequently lapped to provide a coplanar surface of stainless steel and Teflon. A pattern of electrical conductors (30) is then electroformed, as by electrolytic or electroplating, on the exposed surfaces of the mandrel between the embedded Teflon. Surfaces of the electrical conductors of the circuit are then processed, as required for enhanced adhesion to a substrate, and a dielectric substrate of polyamide and acrylic is then laminated upon the surface of the mandrel over the electroformed conductors so that the dielectric substrate adheres to the conductors. The assembly of dielectric substrate and conductors is then separated from the planar surface of the mandrel and its embedded Teflon.