An apparatus is disclosed for holding a matrix during electroforming. The apparatus is secured to the cathode of an electroforming apparatus and consists of a flat disc member having a diameter at least as large as the diameter of the matrix to be duplicated, and a ring member which is adapted to screw onto the outer diameter of the flat disc member so as to hold the matrix in contact with the surface of the disc. Resilient seals are provided in the ring member and disc member which encase and hold the matrix in a liquid-tight fit between the disc member and the ring member during electroforming of replica parts on the surface of the matrix.