64. Bloomery
Emily at the Building Shrine of Giltak
At the Building Shrine of Giltak, I began doing what the gods wanted with iron and steel. Thus, it was finally the day to teach anyone who wanted to learn the art of making wrought iron. I anticipated working through all the different furnaces for processing iron ore over the next few rotations. This way, I could get the iron and steel chore out of the way and get back to living my life. I was looking forward to no further obligations imposed by pesky gods who smiled sympathetically as they coerced me into doing their will. I figured it was better than giving me a choice between doing what they wanted or smiting me, which kept things in perspective for me.
Blooms of wrought iron are made in a furnace called a bloomery. Bloomeries are fun. A bloomery is a freestanding one-use chimney made out of mostly mud. You start a fire in the bottom with charcoal. Once that’s going and the mud of the chimney starts to bake, you add some ore at the top of the furnace, followed by some charcoal, followed by more ore, and so on. All you need to do is keep the fire burning and prevent bridging of the alternating layers of ore and charcoal. The cool thing is the iron isn't supposed to melt. By making so much carbon from the charcoal available in a nice warm place, the iron is chemically reduced. That’s because the oxygen will leave the iron oxide in the ore to shack up with the carbon to make their children, CO and CO2, all without melting the iron. Molten iron will absorb too much carbon, which is bad. That’s why it’s important to not use too much blast from the bellows which will make things too hot and melt the iron.
“I don't understand why the bloomery must be so small?" asked Priestess Artificer Huhoti, Raoleer's deputy for the shrine's foundries. Huhoti was a middle-aged lady with lovely bright green eyes, which was an unusual color for any Cosm. She was also sturdy with buff arms and shoulders from doing a lot of metalwork. She was providing the muscle for the bellows, which were the giant accordion style that could have walked right off the pages of Georgius Agricola’s De Re Metallica and into the Shrine’s foundry. Huhoti explained to me that it’s often less work to use a bellows than to use magic to move volumes of air.
She said gases are tricky to handle with magic. Gasses want to go in directions contrary to the desires of the mage. It got me thinking that maybe whatever the mage was doing did not account for the Brownian motions of gas particles, which can only be described and modeled using the statistical thermodynamics of random or stochastic processes. Running into oddities like that made me wonder how magic really worked in this reality.
I didn’t have time to chew the fat about the intersection of magic and gasses. Everyone attending the wrought iron demonstration was seated in an arc centered on the bloomery and they were watching and also asking questions. The Coyn on were on chairs and the Cosm were on reed mats on the grass. There were over 50 people in total. It was the first time I had seen Cosm and Coyn mingle so closely together.
“So, is there a reason this thing is so small?" persisted Huhoti, who had to be pushing at least 19 hands tall. Damn too-tall Cosm.
I took my tamping tool and made sure no material had bridged the space between the bloomery wall and the pile of alternating iron ore and charcoal inside. "There are several reasons. First, there is a limit on how much ore you can put in before the sheer volume of material starts to w...work against you. On longer bloomery runs, the ore receives more exposure to the charcoal, w...which increases the chance that it will melt in a strong air blast and become unusable pig iron w...with too much carbon in it.
"If you can't forge a bloom, that's a sign you’ve made pig iron. Pig iron is brittle and will fight you if you try to forge it. D...don't throw the pig iron away because y...you can use it in other furnace designs to make cast iron or steel. Today, we w...want to avoid pig iron and make wrought iron, so the faster we can finish the run, the better.”
"Another reason for a smaller furnace is that I know how to use a bloomery and y...you don't, Revered One. This is not a production bloomery, it's a demonstration. We will w...waste less ore this way. Ore is precious until you develop more iron ore sources.” Raoleer had sent the shrine’s artificer trainees down to the Rig River to collect black sand from the sand bars, which is mostly magnetite. Magnetite is heavy so you can pan for it. The mining instructor was ecstatic because the trainees also brought back a pile of placer gold they removed from the black sand.
"Next, Revered One,” I fell into professor lecturing mode on purpose, and gave Huhoti the old raised eyebrow, “it's stupid to build a bloomery taller than the person using the tamper t...tool. I am seven hands tall, which is short even for a Coyn, so I made the bloomery five hands tall. Thus, I have no problems keeping the charge from bridging inside the furnace.”
Huhoti laughed at that.
"There is an alternative to a short furnace. You can build a platform for the people loading the alternating layers of charcoal and ore and for the people w...with the tool to break up any bridging between the wall and the charge. You can even build a really big furnace out of brick that’s permanent, with a permanent gallery near the top for loading the ore; however, that’s a lot of bother if you were me and didn’t need a lot of iron all at once. Did that answer your question, Revered One?"
"Yes," Huhoti replied. "So what's the largest bloomery you've run?"
"It was a charge of about 30 stone of ore. It took a while to consume the charge and half the bloom ended up as pig iron. It w...was not a good furnace run. I cut back to 20 stone after that and haven't had a problem since.” I stopped to lean on the tamping tool, which was a long rod of bronze and took a needed deep breath. I was feeling like I needed to sit down two minutes ago. “Who wants to play with fire? I need to rest for a bit."
"Oh! Oh! Me!" Raoleer jumped up, dressed in foundry leathers and just itching to play with fire. I have to admit I liked Raoleer's attitude. She’s a nerd’s nerd.
I gave her the tamping tool and sat down on the grass close enough to the bloomery so I could listen to it and see what both Huhoti and Raoleer were doing. It was my second break because I was worried I would run out of energy despite using a small charge of only four stones of magnetite, which is approximately two kilos. I asked to have the ore roasted to drive away any moisture so the ore would smelt faster. That was done yesterday.
When I sat down, I knew the bloomery run would be finished soon. I couldn't see the top of the charge anymore so more than half of the charcoal had already been consumed. It wasn’t a big bloomery and it was consuming the charge quickly. The fire inside was the lovely blue of a reducing flame.
Building a bloomery is easy. First, you dig a small hole about as deep as my forearm is long. Then you use cob to build a chimney around the hole. Cob is mostly wet clay mixed with a little sand and a bunch of straw or any other hollow-stemmed grass. If you have lots of stiff clay for your cob, you can just make a round chimney without bracing. Otherwise, you can weave a frame out of something like willow for the chimney if you’re short on clay for your cob. Three artificer trainees did the work of building the furnace chimney for me right after morn repast. It wasn’t hard work either, not for the three Cosm teenagers allowed to get dirty and play with mud.
Every bloomery needs to have one or two holes for air at its base. The holes or hole need to be braced or supported by brick or rocks to allow air in from the bellows. There’s some fancy French name for an air hole on a bloomery but there were no stuck-up historical reenactors in Foskos to be snobby over terminology, so I called it an air hole. It’s possible to just put in air holes at the bottom and let the bloomery draw its own air naturally. Personally, I like having active control over the amount of blast going in instead.
I had run several bloomeries at reenactment events in my previous life. At the end of the run, the handbuilt mud-and-straw bloomery would start to make a noise that was more like a hollow hissing sound. It's hard to describe it if you've never heard it. I was waiting for that moment when the voice of the bloomery changed from a soft roar to a funny hollow hiss. It was a tricky time for finishing the bloom. The bellows operator had to reduce the blast to match the decreased mass of the charge.
My shoulders hurt, and I knew I had overextended myself and would catch grief from my keepers. I was in such pathetic shape. I shouldn't have hurt like this after making a bloom. We had only started two bells ago. I leaned back and stretched out in the cool grass of the lawn, enjoying the feeling of my neck muscles not having to hold up my head. I felt and heard someone walk over and sit down next to me.
"Your face is a little burnt," Thuorfosi said, solving the puzzle of who it was without having to open my eyes.
"Yep, that's about right. Happens every time. It will be gone tomorrow. If my foundry leathers hadn't have been destroyed in the cave explosion, I'd have a face cover to use w...with room for eye protection. I'll make new leathers if I start doing a lot of metallurgy again. At the rate that I'm not getting better, it'll be a while." I tried not to sound too bitter but I found my state of health was bothering me more and more lately.
I enjoyed the feel of the sun on my face. It was still quite nippy out given that the planting season had just started and there was still snow in the northern part of the kingdom. There was no snow at the Shrine of Giltak in front of the foundry buildings, which is where we built the bloomery. I'm not sure if it was this way because of radiated heat from the foundry or if someone magiced the snow away.
I had fallen asleep. I knew this because someone was shaking me awake.
"Great One," it was Thuorfosi. "The Holy One says the charge is almost spent."
"What?" I sat up. How long did I nod off? I hoped it wasn’t too long. I got to my feet and ran over to the bloomery, signaling Huhoti to stop the bellows. I bent down to listen.
"What are you doing?" Raoleer asked.
"Listening. The sound of the bloomery changes when y...you're close to finishing." I walked around the bloomery, listening to it from different places around its circumference. I held my hand over the tuyere pipe, otherwise known as the air hole, to see how hot it was. Putting on my gloves and book mica-covered eye protection, I pulled the pipe from the bellows out of the brick-lined hole.
"Be careful not to step on that," I told Raoleer, pointing at the hot pipe. "Can I have the tamping tool, please?" I got on my knees and looked inside. There was a mass at the bottom, backlit by the fire. I dropped the eye protection over my eyes and got on my stomach to get a better look up the shaft of the bloomery. I poked at it with the tamping rod and saw sparks. I moved it around a little and was confident the bloom had formed and had dropped partway into the hole at the bottom of the bloomery.
"What are you doing?" Raoleer asked.
I got to my knees then stood up. "Take a look through the air hole. It looks like w...we have made a bloom. Seeing that I didn't wake up in time to cut back on the blast, it might not be usable as wr...wrought iron, but at least you've seen how simple this process is. Anyway, take a look. We should let everyone who w...wants to see have a look at what the final product looks like this close to completion. Go ahead and poke it. You'll hear and feel a happy metallic tap which is what you want to hear."
"Huhoti, come over and have a look when the Holy One is done," I waved her over. "After all, you're the one who's done the most work." The bellows were the most labor-intense task in making wrought iron using a forced-draft bloomery. I always used a one air hole design because there was only one of me back when I lived in my sorely-missed valley on the other side of the volcanic rift.
Huhoti and Raoleer traded places. Raoleer crouched down to look at me, which I thought was odd. She looked over at Thuorfosi and nodded. I had a feeling they had something set up. Thuorfosi walked over, put her hand briefly on top of my head, and said, "yes." Raoleer nodded.
"Huhoti," Raoleer addressed her subordinate, "can you shepherd everyone who wants a look in an orderly manner?"
"Yes, Holy One. Great Giltak! This is quite a sight." Huhoti was on her side looking up the air hole at the bloom.
"So, Great One, what happens now?" Raoleer asked me.
"You knock the bloomery over and take out the bloom," I said. "We could refine the bloom tonight, which I w...wouldn't recommend because I’m falling over. But if we did, we could get a start on refining it while it's still hot, since it takes a bit of time to get the forge started up. Alternatively, we can leave it until w...we're ready to start refining and knock it down then."
"Alright, we'll get back to this tomorrow after midday," Raoleer nodded. "She's all yours, Priestess Thuorfosi."
"Thank you, Holy One." Thuorfosi then smiled down at me. "You are just as grimy as you were when the Queen first delivered you to the shrine for healing."
"Some good honest dirt never hurt anyone," I said. "It lets bathtubs earn their keep."
"Yes, bathtubs," Thuorfosi's smile got deeper. It dawned on me that we weren't home in Aybhas, and there was no shower here. Just a Cosm-scaled bathtub and Thuorfosi.
"Well, let's get it over w...with," I said, taking off my eye protection. "I'm in no condition to try and resist the inevitable." I bent over to pick up my gloves and swayed as I straightened up. My vision faded as I lost my balance. Raoleer caught me.
"And this is why we're stopping for now," she said, "because you are ready to fall over."
"I know," I admitted but had no more energy to deliver witty retorts on the way back to the guest house. I fell asleep in the nice warm bathtub and woke in the morning in my bed, scrubbed clean and in my nightgown. I knew Thuorfosi had let me sleep late because the fourth bell rang when I stumbled out of bed.
I was putting my belt on over a worn-out overtunic suitable for getting dirty at a forge when someone knocked.
"Yes?" I called out.
"Seeing if you were awake," Lisaykos said from the other side of the door. "Mid repast is ready."
My foot caught the foot latch and I opened the door, "food is definitely on the agenda."
"Good, because bureaucrats make me hungry," she said. "I'd love to have a few with bacon and lettuce and white egg sauce in one of your sandwich things." White egg sauce is what everyone was calling mayonnaise.
Lisaykos opened all the doors for me between us and Raoleer's dining room. Mid repast was ground elk with mushrooms and onions on brown rice with some kind of brown sauce which was different than gravy. As far as I could tell, no one was doing roux-based sauces yet. It was good and I was really hungry. I even had seconds.
There wasn't much to the afternoon. We started at the bloomery. I pushed it over with my foot. When I knelt to pull out the bloom, I couldn't lift it, to my great embarrassment. It's not that it was heavy, because it wasn't. I was just too pathetically weak. Knocking over the bloomery to get the bloom was a well-attended public event, otherwise, I think I might have wept.
My keeper, Thuorfosi, picked me up and moved me out of the way and Raoleer pulled out the bloom.
"Is it supposed to look like this?" Raoleer asked, turning it over in her hands.
"Yes, that's a nice-looking bloom," I said. "It's supposed to have that sort of spongy, frothy look with little pockets of slag mixed in w...with the iron. Let folks get a look at it and then w...we can go and abuse it in the forge."
After everyone who wanted to look at the bloom had their chance, the small mob of interested people moved inside the main foundry building. Thuorfosi made it clear that I was not walking into the foundry on my own two feet, which left me feeling even more inadequate.
Raoleer's people had built a forge just for this event out of masonry with a draft from the bellows coming up from underneath through a bronze grate. The fuel was charcoal. One side had steps up to a platform for Coyn and the other side had steps down to a dugout area for Cosm. It was rather ingenious, building one structure usable by both human races. The bellows were hard to work from the Coyn side, but that could be fixed at a later date.
I knew I wouldn't be able to do this all afternoon. I was guessing I would last maybe a quarter of a bell at most. Someone had already started up the charcoal so I had Raoleer put the bloom into the already hot charcoal and got the bellows going to heat the bloom.
When it started showing bright red to dull orange color, I pulled it out and put it on the huge slab of bronze which would serve as an anvil surface for now. I used the wedge end of my beloved steel cross peen hammer to cut off a small piece of the bloom and then put the bloom into a corner of the forge.
I heated the small piece to the bright orange stage, pulled it out, and started the laborious process of hammering the slag out of it, explaining what forge refining was while I worked. I was close to a decent, usable piece of wrought iron when the dizziness hit. I dropped the tongs and hammer onto the bronze slab and braced myself against it.
"Somebody make sure I don't fall into the forge, please." Several hands reached out and kept me from falling as my sight faded from a yellow blur to a speckled black and my ears made that hissing noise you hear when you're about to pass out.
I woke up in my bed later that afternoon and heard the sixth bell ringing. I felt like I was living under a permanent cloud of never being able to get better. I was sick of living this way, always tired and weak.
At dinner, Lisaykos determined that I would take a few days off from metal smelting and suggested to Raoleer that I instead instruct the residents of the Shrine of Giltak in the fine art of making kites.
---