How they made iron…
Actually, several different techniques have existed for making iron over the centuries. We’ll go into more detail about some of the others in a future post, but for the time being, let’s just consider how it was done at Beckley.
Beckley was a hot blast furnace — which means that (1) it was a blast furnace instead of a forge or another process, and (2) the blast of air that was forced into the iron mix was heated first. (It’s that blast of air that was forced into the hot iron mix that gave its name to the blast furnace, by the way.)
But let’s back up a little:
What were the ingredients?
The ingredients of iron here at Beckley were:
1. Iron ore (in this case, from the Upper Housatonic area)
2. Charcoal (initially made from trees in the general area, but as demand grew, from as far away as Vermont)
3. Limestone (there are quarries near Beckley — the closest is about a mile down Lower Road)
What was the process?
The process of making iron, once a hot fire was in place in the furnace, involved workers pushing wheelbarrows of iron ore, charcoal, and limestone across a bridge from the charging wall (you can see it on the other side of Lower Road), and dumping them into the top of the furnace.
At the same time, water power from the dam was driving rudimentary air compressors called “pumping tubs” that blew air into a large heating unit called a stove, and from there, blew the hot air into the hearth of the furnace.
The hot air was supplemented by hot gasses from the furnace, largely carbon monoxide, that were piped from the top of the furnace down to mix with the hot air from outside to be blown back into the liquid iron mix.
When a fair amount of liquid iron had accumulated in the bottom of the hearth, a two step process was started. (1) Some of the liquid slag (waste material from the iron making process) was drawn off to solidify into sheets on the floor of the casting shed (it was then broken up with sledge hammers and removed), and then (2) the liquid iron was tapped to flow out into iron molds pressed into the sand of the casting shed floor.
The ingots of iron were (and are) called pigs (we’ll have another post about why they’re called pigs). Once they cooled and solidified, they were carried out of the casting shed and stacked.
And, iron had been made a Beckley Furnace! The process went on over and over, day and night, seven days a week, as long as the furnace was “in blast” (which means in operation).