Cast iron
Cast iron is made from pig iron, which is the product of smelting iron ore in a blast furnace. Cast iron can be made directly from the molten pig iron or by re-melting pig iron, often along with substantial quantities of iron, steel, limestone, carbon (coke) and taking various steps to remove undesirable contaminants. Phosphorus and sulfur may be burnt out of the molten iron, but this also burns out the carbon, which must be replaced. Depending on the application, carbon and silicon content are adjusted to the desired levels, which may be anywhere from 2–3.5% and 1–3%, respectively. If desired, other elements are then added to the melt before the final form is produced by casting.
Waffle iron
Traditional waffle irons are attached to tongs with wooden handles and are held over an open flame, or set on a stove. Most modern waffle irons are self-contained tabletop electrical appliances, heated by an electric heating element controlled by an internal thermostat. There are also two variants of the electric iron: one with removable plates and ones with non-removable plates. Professional waffle makers are usually made of cast iron whereas domestic models are often teflon coated. Many have a light that goes off when the iron is at the set temperature. Most modern waffle irons - particularly cast aluminum ones - are coated with a non-stick coating (e.g. teflon) to prevent the waffles from sticking to them. Cast-iron waffle makers are usually not coated and require seasoning like a cast-iron frying pan.