Abstract: Apparatus in which moulds may be prepared by centrifugal casting comprises a moulding case comprising two plates and spacing means such as two spacing rings therebetween, each of the plates having an opening on or near a central axis of the case for supply of a room temperature vulcanizing (RTV) rubber or molten casting material in the case, means for clamping the two plates together such as a clamping nut threaded on a pillar; and means for spinning the moulding case about a central axis such as a motor-drivable turntable. The moulding case is spun about the said central axis and simultaneously RTV rubber supplied into the moulding case to prepare a mould. A cast may be taken in the resulting mould spinning the mould whilst supplying molten casting material into the mould. Spinning is continued until the casting material has solidified.