Metal was cast in moulds in China long before they were introduced into western Europe in the early 18th century. References to ‘air furnaces’ or ‘cupolas’ for the remelting of pig iron are first found in London and Shropshire. At first, objects such as firebacks and gravestones were cast in shallow open moulds. Other small goods were moulded in movable ‘flasks’ or frames, into which iron was poured from ladles. Larger objects, such as the engine cylinders which the Darbys were making at Coalbrookdale in 1718, were cast in a deep floor of sand. The foundries of the 18th century cast engineering and structural parts, pipes, cannon‐balls, railings, pans, and flat‐irons. During the 19th century moulding and casting plants became increasingly mechanized, and during the 20th century largely automatic.