Ezra was given a green light for the experiments with the refractory bricks, but that was just one part of the plan. He wanted to focus on the steelmaking. For that, he needed a lot of things for the pilot: ore, charcoal, and limestone.
Thankfully, Fulmen had the ability to supply all of it: the coal mines in Abrosite, the ore from Craggy Rook, and limestone from practically every mountain they could mine. While Bren did have refractory bricks, they were not uniform enough for a blast furnace. Ezra wanted to experiment with what combination worked best for his bricks.
Ezra went with his retinue to the outer ring near the smithing district, which was next to the riverside tenements.
There he and his escort were met with men who had coordinated with the Master of Works office. They were escorted by clerks and were met by smiths.
The leader of the party was named Arran von der Schmiedbund, a master smith. He was a commoner who had skill enough to be acknowledged by Draffen himself.
Arran was in his middle years, built thick through the shoulders from a life at the anvil. He was balding on top, black hair left in rough wings at the sides. His mouth sat in a permanent frown, which Ezra didn't know if it was because of habit or if it was just a natural part of his features.
Dynham was in front, while Galwell was much further out, scouting the perimeter like a hawk. For this instance, the whole block was closed off because of Ezra's visit. Aerwyna had all the people that were to be in contact vetted and put through extensive background checks. Because of this, the whole process had been delayed for a week, and even the initial plans for the teaching during Helio were pushed back by two more weeks, but Aerwyna had been true to her word. She had not interfered with Ezra, nor did she even accompany him. However, Ezra had a feeling that she was still somewhere in the vicinity, close enough that she could respond if threats on his life surfaced.
Arran's gaze went to Ezra and held for a beat, then he turned to Dynham.
"Ser Knight," Arran said. "We were told that there is an important project that Maester Draffen has commissioned."
Arran stared at Ezra again.
"We were not told that the little lord was to be a spectator in these events. This is work for men who have experience in ironworks."
Dynham nodded but cut Arran off. "Master Smith Arran, Lord Ezra will not spectate, but rather instruct."
He didn't say anything in reply, but he didn't hide his displeasure, and Arran's frown held. Draffen had taken into consideration Ezra's request for someone who was more open to new methods. Draffen had told him before that even though Arran wouldn't look like it, he would be the most open among the master smiths.
However, seeing Arran now, he was skeptical.
Ezra stepped past Dynham and inspected the location. He checked for cover and water just to get the feel of the entire space. He had already been briefed on everything, but this was his first time seeing the placement.
"We have eight, right? Eight men?" Ezra asked.
A clerk answered before anyone else could. "Aye, eight, my lord. Master Smith Arran and another smith, three laborers, two brick-men, and one kiln-master."
Ezra's eyes moved to the last man.
He was leaner than the smiths, arms corded, with burn-specks on his forearms that never fully left. His nails were black from soot that soap never removed.
"Halvork," the clerk said, as if that explained him.
Arran eyed Ezra again. "We were told that we were going to test brick mixtures."
Ezra nodded. "Yes, Master Smith."
"The purpose being?" Arran said.
"This is building blocks for something that can hold a hotter fire than your forge. Hot enough that the dirt turns to slag on its own, and the iron can run."
Arran gave Ezra a quizzical look. He was about to go when he hesitated, opened his mouth, and said, "Our forges burn hot enough."
Ezra nodded once. "Hot enough to soften iron, yes. I need heat that keeps it liquid while the slag runs. If the slag sits, it eats the lining. If the lining cracks, the furnace dies."
Arran stopped. He was taken aback, like he didn't expect the boy to actually give a coherent and in-context answer.
"How do you know, boy?" Arran said stiffly.
Dynham's gaze sharpened. He was about to shout, but Ezra waved his hand to stop Dynham.
"Our kilns can burn very hot, that I am sure...." Arran's face stiffened, then he added, "My lord."
"Yes, but the problem with your kilns is that we don't have reliable enough brick for what we want."
"And what is it we want?"
"A tall furnace," Ezra said. "Something that doesn't stop heating. We want the slag to be continuous."
"A new type of furnace?" Arran asked. There was a hint of sparkle in his eyes, but his countenance held.
"Yes," Ezra nodded.
"This... whatever we are tasked here will contribute to that?"
"It will."
Arran finally gave a snort and left.
When Arran was quite some distance away, Dynham opened his mouth. "Milord," Dynham exhaled, "why did you let him disrespect you like that?"
"He is just too passionate about his craft. I kinda get him. If I were in his situation, I'd probably ask questions too."
The whole day, Ezra had directed the workers on various tasks. He had them line up different types of clay from different sites. He had them make different mixtures in different proportions. After the deed was done, he had twenty separate mixtures of various viscosities.
He had the workers crush old brick into powder. Fired brick. It had already lived through a kiln once, so it would not shrink again. For some of the containers, he had a mixture of sand and crushed brick too. The result at the end of the day was three hundred different mixtures of various consistencies. He used AMP so that the measurements would be precise. He had gained the capability to measure not just single object trajectories, but now he could "assign" things in aggregate that his mind could deem a single unit. He still didn't know the mechanism of the ability, but it operated on his own perception.
He had the ratios and materials dictated and recorded by Caspian while Hearth checked the fire.
By the end of the first day, the work yard had a row of wet bricks laid out under cover, each marked. Ezra walked past them, checking for blemishes or any inconsistencies just to double-check.
He also had them make small slabs, thin pieces, for fast testing. A full brick took longer to fail. A thin slab would crack quickly if it was going to crack at all.
The first firing took most of a day, and then the waiting started.
The kiln glowed, and heat bled out of it in waves. The workers sweated and cursed and fed it more fuel. Ezra stood back and watched. Watching was still work. If he looked away and the fire dipped at the wrong time, the whole batch would lie to him.
He used AMP to check the precise temperature of the kiln, the time it took to get there, and how long each mixture baked.
He watched the bricks while they were still inside, watched the surface, watched the tiny lines appear and spread. How some mixes moved as they heated. How they slumped at the edges. Some did not move, but began to web with cracks.
Ezra made notes on his ruled notebook, fresh from the press. It was coordinated to which batch did what, and what mixture it had been. It was arranged in a neat table.
When the kiln finally cooled enough for the workers to pull the pieces out, Ezra sorted them by sound. He struck them lightly with a rod. A clean ring stayed. A dull thud went to the discard pile. It was not perfect but it was fast.
He repeated the cycle.
Heat. Cool. Heat again.
He knew that this wasn't the best way to make the most optimal brick, but at least with AMP he could be much more precise. For now, this was the best that he had, and that was enough for now.
By the third day, the yard had two piles. There were five different mixtures that he had appraised as the best.
From the five different mixes that passed Ezra's scrutiny, he went to the next phase and tested their tolerances.
He even had Reitz visit at one point, just to make him cast a spell and check the threshold of heat they could take. Reitz could modulate the heat of his [Flame Blaze] spell, which was actually quite surprising to Ezra.
When he was satisfied, he moved to the next phase.
He took slag from a forge, and the smiths smeared it across the surface of the best candidates.
A week had passed until he was finally satisfied with the end result. AMP had helped out immensely. He was sure without it he wouldn't have finished his intended goal within the week. AMP removed all the guesswork and turned it into something accurate, up to even the temperature needed.
By the end of the week, Ezra had a ratio he trusted. He knew it wasn't perfect, but it was just enough, so much that it could be produced en masse with acceptable deviation.
He had a clay source he preferred: the kiln yard clay, tempered with crushed fired brick in a heavier proportion than the masons liked. It made a brick that was slightly rougher to cut and seat, and that was fine.
He encircled the final composition in his notebook, gave Caspian the notes, and had them pressed in the Press office, a copy of which was to be handed to Draffen.
"Are we done with the mixtures of the bricks we want?" asked Arran.
"Mhm." Ezra nodded.
"And this will help?" Arran followed up, still eyeing the child.
"You saw what the bricks can do," Ezra said.
"Bricks are bricks. We can only be sure when you stack them and make what you want," Arran replied gruffly.
For the next phase of the project, Ezra went to Draffen's office. He gave the new plans to Draffen.
"Pray, tell Lord Ezra, how fared your bricks."
"It was promising," Ezra replied.
"Promising?"
"I have given you the packets and copies of the ratios, the methods, and what to use. We can create the bricks consistently enough that we don't have to remake kilns after a few uses."
"That you did. Your working mix is what you expect?"
Ezra nodded.
Draffen's eyes didn't leave him for a beat, then they dropped to the papers. He set them square on the desk, aligned to the edge as if that alone made the world easier to handle.
"Then I assume you are not here just for light conversation." Draffen paused. "What is it that you need?"
"We want to create a different structure from our current furnaces."
"You mentioned that before," Draffen said. "Arran also mentioned this in our correspondence."
Ezra slid the next sheet forward.
It was a taller drawing, a cutaway of a furnace from mouth to hearth. The lines were straight where they needed to be, curved where the shape mattered. He had filled it with arrows. Downward arrows for the charge. Side arrows at the tuyeres. A thin rising line at the center for the hot breath.
The parts were labeled in simple words. Top. Stack. Belly. Hearth. Tuyeres. And at the bottom, two small channels drawn like veins: one for slag, one for iron.
Draffen read without speaking. His nail traced the outline once. Up. Down. He tapped the belly. He paused at the tuyeres. He tapped again at the bottom runnels.
"This… design." Draffen furrowed his brows. "Why is this a tower?"
"It's supposed to be tall."
Draffen didn't speak, but stared at Ezra with a questioning gaze.
"The heat needs enough space," Ezra said, "such that the ore needs time to change before it reaches the bottom."
"Change?"
"We need to roast the ore, then soften it enough to melt."
"Roast?" Draffen repeated. "Like meat?"
Ezra paused. He didn't smile. He kept his hands still. "What we do is we heat it before it goes in. The wet ore steals heat. After that it spits. It makes mud inside the stack. If we roast it first, it goes dry and brittle. We can break it to a clean size, and the air can pass through the charge. Then the bottom stays hot instead of fighting steam and clumps."
Draffen's nail tapped the top of the stack, where Ezra had drawn the mouth. "You want a separate fire for ore."
"Yes."
"And you want it measured," Draffen said, more statement than question.
Ezra nodded once.
Draffen's gaze moved back down the drawing. "And why do we need to do all of these things? What good does this bring? We can make enough with our own furnaces."
Ezra looked back at the cutaway. "We can make enough for a few smiths. We can't make enough for a city."
Draffen's face stilled. "And with this method, a furnace can provide for a city?"
"Well, much more than what we have now," Ezra replied. "With this method we can feed many forges."
Draffen studied Ezra again. His expression didn't change, but his attention sharpened, as if he had moved from indulgence into cost.
"Did Maester Faraday mention this in the notes?" he asked.
Ezra nodded reluctantly.
Draffen's nail tapped once on the desk, near the drawing. "What do you need for this?"
"We need stone for the outer shell," Ezra said. "Lime mortar. Maybe imperial concrete for the base, if you allow it."
Draffen nodded, then continued to stare, eyes on the belly of the furnace as if he could already see where it would crack.
"Tuyeres," Ezra continued. "Several. And a steady blast. If the air is consistent, the furnace stays consistent even when I'm not standing there."
Draffen's gaze lifted a fraction. "What of air?"
"We do need something," Ezra said. "Bellows. A wind box. Something to smooth it."
Draffen's mouth tightened. "Charcoal as well, I presume, or coal?"
"Charcoal for now," Ezra replied, "but if we can further process coal, then that would be better."
Draffen raised his brow. For a moment it looked like he was going to ask what Ezra meant by "process." Then he didn't. He filed it away.
"Then, finally," Ezra said, "ore and limestone to make the dirt run as slag."
Draffen stared at the bottom of the drawing again, at the two channels. "Slag run. Iron run."
Ezra nodded.
Draffen's fingers rested on the edge of the parchment. "I will send men to supply you with a certain allocation," he said. "I have to liaise with Corvin to finalize the sum and get the difference from the coin that Lord Blackfyre allocated for you."
Ezra smiled. If he could get the blast furnace to work correctly, he could increase the revenue of Bren and provide enough raw material for the next phase of his plans.