The lower casting apron smelled of scorched sand, damp clay, and the heavy, sweet metal tang of molten stone.
In the floor of the foundry shed, two deep channels had been carved into the packed quartz dust sand, lined with heat-proof loam and dried with glowing charcoal fire bowls.
The lower channel, sixty feet long, led to a herringbone pattern of sixty single casting beds stamped into the floor—the ‘pigs’ and their feeding ‘sow’.
The upper channel, branching off eighteen inches higher on the fire face, led straight out of the building toward a deep, box-shaped stone tank filled with rushing river water.
Giles Croft stood by the melted rock waste notch, wearing heavy leather gaiters that reached to his knees and a pair of dark ironworker’s goggles pushed up onto the brim of his cap.
In his gloved hand he held a six-foot steel-tipped tapping bar.
“The melted rock waste notch sits fifteen inches above the iron taphole,” Giles said. He pointed the bar at a small, circular plug of plastic yellow clay set into the fire wall. “The molten iron, with a specific gravity of seven point two, settles to the bottom of the crucible. The liquid melted rock waste, with a specific gravity of about two point eight, floats on the metal bath like cream on milk.”
Master Borin Bronze-Lung stood on the other side of the runner with an eight-pound sledgehammer held in both hands. His copper-braided beard was tucked securely into the breast of his leather coat.
“Ready on the steel, Lord Giles,” Borin rumbled. “The pressure behind that clay plug must be twenty pounds. The moment the bar breaks the crust, she’ll come out like a dragon’s spit.”
“Stand on the upwind side of the sand runner,” Giles directed the crew. “And keep your goggles down. Liquid stone-glass has high water’s skin. Any moisture in the sand runner will trigger violent steam-spall.”
Duncan Stone-Splitter and six masons stood along the outdoor channel, holding long-handled iron rakes.
Beside them, the granulation pit bubbled and surged. It was a twenty-foot stone tank fed by a diversion water chute from the drainage canal, four feet deep and filled with icy river water rushing through at three hundred gallons per minute.
“Why waste time catching the scum?” Duncan asked, leaning on his rake. “In the old iron camps in the hills, they let the melted rock waste puddle in the dirt, break it with hammers when it cools, and dump it in the river. It’s just molten glass and dirt.”
“Dump it in the river?” Giles paused, looking at Duncan with genuine office horror. “Dump five tons of high-calcium aluminosilicate into an active riparian waterway? That’s a flagrant rule-break of the Frontier Municipal Riparian Protection Act. An appalling waste of cementitious precursors.”
Duncan blinked. “Precursors?”
“Standard blast-fire melted rock waste contains forty percent calcium oxide and thirty-five percent silicon dioxide,” Giles explained. “If you allow it to cool slowly in air, it crystallizes into inert, useless melilite rock. But if you cool it in a heartbeat in cold water, crystal-forming is arrested. It freezes into an amorphous, glassy glass with latent high-pressure properties.”
Duncan scratched his head. “Glass with what?”
“Volcanic cement,” Giles said. “Grind that cooled glass sand into fine powder, mix it with ten percent wet lime plaster. You have high-pressure cement that cures under water and reaches five thousand pounds of pressure of crushing strength. It turns heavy-duty waste into roads, bridges, and sewer arches for zero material cost.”
Duncan’s jaw dropped. He looked from his iron rake to the stone water tank.
“You’re making stone... Out of the trash from making iron?”
“Nothing is trash,” Giles said mildly. “Trash is merely a glitchy inventory category. Borin, strike the plug.”
Borin raised the sledgehammer. He swung with the practiced, devastating rhythm of a dwarven master smith.
CLANG.
The hammer struck the head of Giles’s steel bar. It drove the chisel point deep into the baked clay plug.
CLANG. CRACK.
The clay seal fractured.
A blinding, incandescence burst through the hole.
It wasn’t red. It was a glowing, radiant river of golden-white liquid glass. It poured from the fire throat with a thick, syrupy hiss.
The molten melted rock waste surged down the sand runner at two thousand two hundred degrees Fahrenheit, lighting up the wooden beams of the foundry roof in a dancing, orange-tinted glare.
The heat streaming from the open runner struck Giles’s face like the blast from an open oven door, baking the leather of his apron and filling the shed with the clean, rotten-egg aroma of molten stone.
The glowing torrent reached the outer doorway. It surged down the sloped granite chute and plunged straight into the icy waters of the granulation pit.
KA-SHHHHHHHHH.
An ear-splitting, nonstop roar of exploding steam blew up across the terrace.
A huge geyser of brilliant white vapor shot forty feet into the autumn sky, billowing across the river docks in a dense, swirling cloud that smelled of hot stone rain.
Beneath the churning water, the heat shock was total.
The liquid stone-glass, hitting the cold river current, didn’t form boulders or slabs. The sudden, violent contraction shattered the molten glass stream into billions of tiny, golden-amber granules, sparkling like coarse diamond sand as they settled to the stone floor of the tank.
Duncan Stone-Splitter stepped to the edge of the pit, shielding his face from the billowing steam.
He plunged an iron rake into the water and hauled up a dripping mound of the cooled material.
It was a glistening, pale honey-colored gravel, sharp-edged, porous, and cool enough to touch within twenty seconds of leaving the two-thousand-degree fire.
Duncan rubbed a handful of the glassy sand between his palms. It crunched like crushed crystal.
“Glass sand,” Duncan whispered, his voice shaking with total, stunned disbelief. “Hotter than the pit of hell ten seconds ago. Now it’s cool sand that makes bridges. He doesn’t just forge iron... He makes the world twice over.”
Lady Beatrice of Dunwall stood on the upper narrow high walkway. She watched the white steam plume roll across the Black Fen.
She turned to Lady Millicent, who was quietly noting the tonnage in her tally-book.
“Five tons of high-pressure cement per heat,” Beatrice murmured softly. “Do you have any idea what the Guild of Masons in Highmarch pays for fiery volcanic cement imported from the southern isles?”
“Twelve gold sovereigns per ton,” Millicent answered without looking up from her ledger. “Plus carriage insurance. Grey Crag will retail this granulated melted rock waste to Duchess Rowena for five sovereigns per ton, FOB river wharves. We anticipate a six-hundred-percent return on our lime investment within ninety days.”
Beatrice closed her eyes for a moment, letting out a faint, overwhelmed breath. “Your brother isn’t a baron. He’s a financial plague disguised as a land-mapper.”
“Giles is an engineer,” Millicent corrected with quiet pride. “Which is considerably more dangerous.”
Down on the casting floor, the flow of golden melted rock waste began to thin.
The blazing bright stream sputtered, and a dark crust of solidified stone-glass began to form across the lip of the notch.
“Melted rock waste layer cleared,” Giles called out, using an iron skimmer to sweep the runner. “The metal line is within three inches of the notch. Plug the melted rock waste hole, Borin!”
Borin drove a fresh cone of moist, fireclay-and-graphite paste into the opening with a heavy wooden rammer. The clay baked instantly against the glowing stonework, sealing the notch tight.
Toby Karr was walking the length of the casting floor with a wooden pattern-box, stamping the sand beds into crisp, uniform trenches.
“Sixty pig beds, Lord Giles,” Toby called out, wiping sand from his leather apron. “Each mold is four feet long, four inches wide, and three inches deep. That calculates to exactly fifty pounds of iron per pig, with a three-inch draft angle on the sides so the cooled bars tap out cleanly without breaking the sand.”
“Good draft angle,” Giles approved, inspecting a test depression with his wooden ruler. “If the draft angle is too steep, the cooling metal bar binds against the sand walls as it contracts, causing surface tears and sand inclusions. Keep the runner channel crowned an eighth of an inch to prevent stall.”
Beside the runner, Master Borin Bronze-Lung examined a pair of heavy iron skimmers.
“In the high halls of Karak-Thurn,” Borin said, his copper-braided beard twitching with skilled pride, “we cast iron into iron chills—permanent molds machined from heavy grey iron. But sand beds are forgiving. If a heat runs hot or carries a touch of sulfur, the sand vents the steam through its pores without popping.”
“Sand beds need zero capital tooling,” Giles noted. “And the moulding sand is ninety percent local river silt hardened with five percent ball clay. When the pigs are lifted, we simply rake the beds, wet them down, and stamp them again for the next heat.”
“Hearth is clean,” Borin shouted, wiping sweat from his red beard. “Twelve tons of virgin molten iron sitting on the crucible floor, Lord Giles! She’s ready to pour!”
Before Giles could reach for the iron tapping bar, a sharp clatter of armored boots echoed from the northern apron.
Sister Teresa marched out from the sick room tent. Her high-pressure burned lime powder lance held at port arms. Her wimple was pinned tight against the wind, and her eyes flashed with holy, rule-book fury.
“You bring smoking charcoal pans into an active foundry apron?” Teresa demanded, leveling her brass nozzle directly at the lead paladin’s chest. “Section Twelve of the Town Fire Safety Mandate strictly prohibits open burning within fifty paces of the casting beds! Put out those censers, holy father, or by the Cistern, I’ll deluge your incense with forty gallons of wet lime plaster!”
The paladins didn’t flinch, but their eyes widened as they took in the hissing brass nozzle and the two apprentices pumping the chemical tank behind her.
Captain Kenneth Drake stepped into the doorway, his hand on the handle of his broadsword, his jaw tight.
“Giles,” Kenneth said, his voice flat and dangerous. “The Synod has landed.”
Giles looked up.
Marching through the outer timber gate was Judge Malric Ostrander. He was flanked by twenty armored paladins in full plate armor.
The paladins carried heavy iron-bound heater shields and notched poleaxes, their white surcoats bearing the radiant sun-wheel. In their left hands, four officers carried smoking iron censers swung on heavy brass chains. It filled the crisp river air with a choking, greasy haze of consecrated myrrh.
Ostrander marched directly to the edge of the casting floor, his black glass mantle sweeping the sand.
He halted ten paces from the fire stack. His eyes burned with fanatical, prosecutorial fury as he looked from the steaming granulation pit to the roaring forty-foot tower.
In his right hand, Ostrander raised a heavy iron brand, forged in the shape of seven linked rings—the Seven-Ring Seal of Heresy.
“By the sovereign power of the Holy Synod and the Light of the Sun-Wheel,” Ostrander’s voice rang through the shed like a cracked bell, “this unholy engine of the Black Flame is declared a monster against the Divine Order! In the name of the Grand Judge, I order this hell-mouth put out and its master bound in chains!”