I built my first bloom furnace because I already had some experience with making blooms. A friend and instructor who taught me quite a bit about smithing also taught this skill. It is rare knowledge now, practiced by relatively few people.
Modern steelmaking replaced it for a reason. The modern process is, unarguably, superior if the goal is producing consistent steel efficiently. A bloom-furnace run is not about creating some kind of super metal.
It is about the tradition.
An individual can still make metal from dirt without a laboratory, a modern factory or heavy machinery. There is a kind of magic in that creation. The metal has a life to it—a visible grain and flow that I find aesthetically pleasing.
That was why I wanted to demonstrate the process. It was engaging, entertaining and educational, and it connected local heritage with something most people had never seen.
I gathered the hematite over several months, mostly from creek beds. I would drag a strong magnet through the sand and pick up small pieces of black or red hematite. Occasionally I found a chunk. Most of the time, I was brushing a little dust into a jar and slowly collecting enough to use.
The ore is local. Land Between the Lakes once supported a historic iron industry. The resources did not simply disappear; the industry was replaced as other areas became better suited to modern production.
The furnace itself was made from an adobe-like slurry of clay, sand, refractory material and manure. The clay provided the structure. The sand and refractory material helped insulate it. The manure acted as a binder. Its small fibers helped keep the furnace from separating as the mixture shrank and dried.
The run lasted about nine hours. Most of it went well. The trouble came at the end, when the bloom fused to the furnace wall.
I had to smash the furnace to remove the metal. That was sad, but the furnace was made from poo and mud. It was never meant to last forever. I was not out anything except the time it took to build.
Opening the furnace was not a grand reveal where I immediately saw a perfect glowing bloom. I could barely see anything. It was hot enough to sunburn me through my clothes. I spent most of my time removing superheated coals from as far away as I could manage, only to discover that the bloom was fused to the wall anyway.
Getting the bloom out was only the beginning. Refining it was a chore, and it required a great deal of fuel.
I worked it at the charcoal forge at the Homeplace. The piece had to reach welding temperature. Then I slowly tapped it together to compress it. After that, I folded and forge-welded it several times until it developed a grain structure that would hold together under real hammering.
It took more passes than I care to count.
The historic ironworkers of this region had a similar, though not identical, problem. Their furnaces produced pig iron. That material then went to mills, where it was worked into wrought iron—literally worked iron. That process was every bit as labor intensive as the work I faced refining my bloom, only on an industrial scale and as part of a larger chain of labor.
I have run the furnace four more times since that first attempt. Each run brought tweaks and changes. One improvement was using firebrick for the furnace structure and coating it with the refractory mixture. That saved construction time and effort. It also saved the furnace when another bloom fused to the side. Instead of crushing the entire structure, I could dislodge the bloom and put the bricks back in place.
The photographs with this post are snapshots of the process, beginning with the furnace in operation and following the bloom through refinement into a billet.
The billet is small compared with the months spent gathering ore, building the furnace, running it and refining the metal. But the quantity of metal was never the whole point. The point was proving that the old knowledge still works—and that a person can still take local dirt, fire and a great deal of labor and make iron by hand.