Cast iron requires a specific set of conditions to be made. These peculiarities have generated not only a material with both a recent and interesting history, but also a material known for a variety of uses.
Furnaces did not burn hot enough to create cast iron until the medieval era in Europe. According to Professor Joseph S. Spoerl, cast iron "contains from 3 to 4.5 per cent carbon," which renders it brittle beyond working. It was during the late Middle Ages, Professor Spoerl states, that a "blast furnace" was created. This new furnace held an intense build-up of heat and the molten iron flowed through materials and into a row of troughs. From there the iron was "cast" into moulds.
There are two main uses for cast iron: architectural and domestic. Though fairly difficult to create, cast iron is famous for its durability and therefore used in a variety of locations. You may notice cast iron bridge details, rails, pillars, benches, pipes and old storefront facades in older sections of towns and cities. Household items include hefty cookware like cast iron pots, pans, kettles, grills, and detailing like knobs and doors.
Because cast iron is both hardy and delicate, watch carefully for signs of wear and tear. If you notice rusting, corrosion, or other forms of deterioration, immediately assess the damage. For architectural work, architect John G. Waite recommends seeking a good contractor, stating that "If there are major problems or extensive damage to the cast iron, it is best to secure the services of an architect or conservator who specialises in the conservation of historic buildings."
For smaller cast iron peices like those used in cooking, remove light rust with a wire brush. Discard cookware with more extensive damage.
Though cast iron is a very strong material, its porous nature requires special attention. According to Waite, cast iron's main weakness is tension, and will snap when strained. It is important to routinely check any architectural cast iron for deterioration. As for cooking ware, cast iron deterioration can advance quickly in unseen air pockets and casting flaws, which can also affect the food you cook. Do not use copper to clean cast iron; the two materials run the risk of electrolytic reactions.