Ironfounders and Engineers
Until the Abraham Darby experimented with using coke, first at Baptist Mills in Bristol and especially at Coalbrookdale in Shropshire, smelting and casting of iron was largely confined to forested areas where both charcoal and iron ore were produced, notably the Weald of Sussex and Forest of Dean.
The new industry, from the beginning of the 18th century, produced huge quantities of iron that was traded down the Severn and through the Coalbrookdale company’s warehouse in Bristol. In many towns local iron founding firms developed, often from among the blacksmiths who were already working wrought iron.
Bradford on Avon had three foundries at one time, operating between the 1820s and 1960s and their products can be seen in the streets of the town today.
The foundries also cast in brass, the alloy of copper and zinc, usually using it to make smaller, more intricate articles. Before the experiments of William Champion, again in Bristol, brass was largely used in sheet form, made by hammering in water-powered mills. Zinc vapourises at a relatively low temperature and the only way combine it was to expose the copper to heated zinc ore. Champion managed to refine zinc metal by letting it form in cool chimneys (the sublimation process). Like pig iron, brass pigs fairly quickly became available for local foundries.
The foundries dealt with all sorts of engineering in metals, from buildings, millwrighting for the wool and rubber factories, agricultural equipment, road transport, down to railings, gates, domestic heating, water supply and drains.