Abstract: Apparatus for horizontally plating one surface of conductive sheet with a metal or metal alloy. The apparatus includes an electrolyte holding tank, a horizontally disposed enclosed electrolyte conduit having extended inlet and outlet portions, a variable speed pump for passing electrolyte from the holding tank through the conduit and a rectifier for supplying electrical current. The holding tank includes means for dissipation of entrapped gas bubbles generated during metal deposition or caused by aeration. The conduit has a horizontal opening including an insoluble anode within the opening for defining a plating cell. The anode is positioned parallel to the axis of the conduit and in alignment with the opening. The plating cell includes means for supporting the sheet above the opening. The inlet and outlet portions of the conduit are positioned in-line with the plating cell.