Expandable hot top for ingot moulds

An expandable hot top for ingot moulds comprising two pairs of preshaped end panels, flexible means hinging said end panels to one another, two preshaped side panels, flexible means hinging said side panels to said end panels in an arrangement wherein the two pairs of end panels fold inwardly against each other to a position between the side panels, hangers with inturned and upturned lower ends and outturned upper ends positioned in apertures in said end panels, whereby movement of the end panels into end-to-end to end relation, moves the side panels outwardly to form the hot top, locking bars positioned across the inside of said end panels between and in engagement with the upturned ends of the hangers hold the hot top in expanded open position in the ingot mould.