The rates of electropolishing of vertical copper plates in H3PO4 placed downstream of a H-2 evolving cathode were studied by measuring the limiting Current of the diffusion controlled process under different conditions of H-2 discharge rates and H3PO4 concentrations. The mass transfer coefficient was found to Increase with H-2 discharge rate raised to the exponent of 0.4. Within the studied experimental range of conditions, the rate of polishing increased by a factor ranging from 1.95-5.8, depending on the H-2 discharge rate and H3PO4 concentration compared to the natural convection value. The results are explained in terms of surface renewal theory. The proposed electrochemical reactor offers the advantage of increasing the rate of electropolishing without consuming external stirring, energy as opposed to traditional electrochemical reactors.