Blast Furnace

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.

  • Bog ore is an iron-rich rock that was harvested locally from bogs and similar bodies of water. It was also found in fields and meadows that used to be bogs. Bog ore is often considerably less than 50% iron. The rest of the rock was made up of impurities that the workers had to remove.
  • Charcoal was needed to fuel a fire that would burn hot enough to smelt the ore. Charcoal production was very labor intensive and required the work of many woodcutters, carters, and the colliers who oversaw the conversion of seasoned wood into charcoal.
  • Gabbro was used as a flux; a way to purify the ore. When gabbro was melted with bog ore, the impurities in the ore latched onto elements in the gabbro. All of those impurities floated to the surface while the dense iron sunk to the bottom, creating a separation of good iron from the waste.
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.

Places at the Saugus Iron Works
| Visitor Center | Museum | Iron Works House | Herb Garden | Blast Furnace | Forge | Slag Pile | Rolling and Slitting Mill | Warehouse anf Dock | Blacksmith Shop | Saugus River and Nature Trail |

Last updated: October 19, 2016

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Mailing Address:

244 Central St
Saugus, MA 01906


(781) 233-0050

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