Apparatus for cladding and thus reclaiming a worn rolling mill roll by fusing a surface layer thereon, comprises an electro-slag mould (7); a slewable derrick structure (Fig. 2) able to feed a split tubular, consumable electrode (51) into the mould; a turn-table (8) supporting the mould; a tiltable induction furnace (55) to charge the mould with molten flux; product transport means (Fig. 1) to lift a worn mill roll through the mould and withdraw it downwardly from the mould as cladding proceeds and comprising rigid hangers (12) extending downwardly from the turn-table, an elevator carriage (14) with a product holder and adapter including a mould plug (29), and power driven jack screws (19) to raise and lower the carriage (14); and drive means (9, 11) to cause rotary oscillation of the turn-table and the components carried by it, including the roll, relative to the electrode. A method of cladding a worn roll by the electro-slag process is also disclosed wherein the mould and roll are rotationally oscillated about the axis of the roll relative to the electrode, as cladding proceeds.