Method for the manufacturing of a two-layer metal wire, made of a gold-based alloy and of silver, comprising a succession of steps comprising: - coupling a gold-based alloy of Au-18kt type or of Au-14kt type outer metal tube to a silver alloy of Ag725 type inner metal tube by interposing a first binding thickness made of copper (Cu), - welding in a furnace equipped with belt conveyors defining a movement direction, said furnace having a first combustion chamber and a second combustion chamber at different temperatures, the inner surface of said outer metal tube to the outer surface of said first binding thickness and the inner surface (13") of said first binding thickness to the outer surface of said inner metal tube in order to firmly associate said outer tube and said inner tube together, wherein some gold particles migrate into the silver layer and vice versa and the heat of the furnace causes the particles of the first binding thickness to migrate so as to make them interpenetrate into the outer and inner metal tubes and, similarly, the particles of the tubes merge with those of the first binding thickness so that the first binding thickness is removed from the user's eye thereby forming a tubular element (7, 107) having two metal layers, - optionally coupling a support thickness internally to said inner tube, wherein, preferably, the outer surface of said support thickness is welded to the inner face (14") of said inner metal tube so as to form a tubular element consisting of three metal layers, and - drawing, by means of a final drawing process, said tubular element (7, 107) to obtain a compound metal wire made of two or three metal layers - coupling a gold-based alloy of Au-18kt type or of Au-14kt type outer metal tube to a silver alloy of Ag725 type inner metal tube by interposing a first binding thickness made of copper (Cu), - welding in a furnace equipped with belt conveyors defining a movement direction, said furnace having a first combustion chamber and a second combustion chamber at different temperatures, the inner surface of said outer metal tube to the outer surface of said first binding thickness and the inner surface (13") of said first binding thickness to the outer surface of said inner metal tube in order to firmly associate said outer tube and said inner tube together, wherein some gold particles migrate into the silver layer and vice versa and the heat of the furnace causes the particles of the first binding thickness to migrate so as to make them interpenetrate into the outer and inner metal tubes and, similarly, the particles of the tubes merge with those of the first binding thickness so that the first binding thickness is removed from the user's eye thereby forming a tubular element (7, 107) having two metal layers, - optionally coupling a support thickness internally to said inner tube, wherein, preferably, the outer surface of said support thickness is welded to the inner face (14") of said inner metal tube so as to form a tubular element consisting of three metal layers, and - drawing, by means of a final drawing process, said tubular element (7, 107) to obtain a compound metal wire made of two or three metal layers