A method or apparatus for joining a first component to a second component with an amalgamation plate includes heating the first component, the second component, the amalgamation plate, or combinations thereof, with either a joining tool or a heating element. The components are attached to the amalgamation plate with the joining tool, such that the first component, amalgamation plate, and the second component are fixedly attached to one another, and the amalgamation plate may be substantially surrounded by the first component and the second component, such that it is hidden from exposure. Portions of the amalgamation plate may be embedded into the components via rotation and/or linear force. A portion of the amalgamation plate may be recessed within the joining tool or an anvil before attaching the amalgamation plate to the either component.

An amalgamation plate for joining a first component to a second component has a planar body configured to be placed between the first component and the second component, and a plurality of first protrusions extending from a first side of the planar body. The first protrusions are radially dispersed from an axis of the planar body, and are configured to be embedded within either the first component and the second component. The amalgamation plate may also have a plurality of second protrusions extending from a second side, opposite the first side, of the planar body. The second protrusions are radially dispersed from the axis, and are configured to be embedded within the other of the first component and the second component via application of force substantially along the axis. The first protrusions and the second protrusions may be radially symmetric about the axis of the planar body.

A method of securing a first component part and a second component part together, the method comprising providing an electrically conductive member between a first surface of the first component part and a facing first surface of the second component part and securing the first and second components together by passing a current through the electrically conductive member. The electrically conductive member may comprise a first portion connectable to a source of current and a second portion electrically connected to the first portion and comprising a plurality of sub-conductive members. The electrically conductive member may be distributed across at least 50% of the surface area of the first surface of the first component part.

An implant for electric resistance welding of elements made of composites, with a frame of thermoplastic materials, reinforced with conductive fibres, in a flat multilayered structure with an upper and lower surface, and includes an electrically resistant layer of a flat sheet with openings, made of a conductive material, additional layers made of the frame material, one of which covers the electrically resistant layer from the top, and the other one from the bottom. The implant includes porous insulating layers made of an electrically nonconductive material, one covers the implant from the top, contacting the upper layer of the frame material, and the other covers the implant from the bottom, contacting the lower layer of the frame material. The layers are merged with each other in a flat, multilayered inset placed between the welded elements, and the electrically resistant layer has electrical connections for connecting a source of electrical current.