A method is outlined for the manufacture of small thin metal shells. Details are given of the production of a spherical copper shell of diameter 6 in., and wall-thickness 0·004 in. The shell is deposited electrolytically on a wax surface of the appropriate shape, and the wax is subsequently melted away. Arrangements of anode and cathode in the electrolysis process are examined for uniform thickness of metal deposit on surfaces of various shapes.