In 1646, the original blast furnace roared to life, lit with a 3000 degree fire that was kept burning 24 hours a day for months at a time. The blast furnace is where bog ore was smelted to create cast iron "pig" bars. To do this, three types of raw materials were brought over the charging bridge and loaded into the chimney of the furnace.
The casting shed at the base of the furnace is where the iron and waste were removed from the furnace. When the furnace was tapped, the waste was drawn off to the side where it hardened to create slag. The good iron flowed into channels dug into the casting shed's sand floor, where it hardened into cast iron bars referred to as "pig iron." These bars had a very high carbon content, which made them very hard, but also brittle. They had to be further refined in a forge before a blacksmith could use them to create finished products.
Gray iron was also poured into molds in the casting shed to make finished products including pots, kettles, skillets, firebacks, salt-pans, and even parts of the machinery used at the iron works. Just like the bars of pig iron, these finished products would be very hard, but also very brittle. Therefore, cast iron was only ideal for making certain products.
Last updated: October 19, 2016