Day 25, the sun cast its first pale rays over the horizon, yet it was stingy with any warmth.

Lin Yu'an stood before the mobile ice fishing shack he had painstakingly built in a day, carefully inspecting the tightly woven willow branches, ensuring every knot was firm and reliable.

This wooden shack was a qualified "shield," but he still needed a "spear," an ice drill spear capable of piercing thick ice.

He knew full well that he could just go over with the Forest Axe now, and with his stamina, take some time to chip a hole in the thick ice.

But that would be a short-sighted strategy.

Facing the camera, his voice was low and serious: "Sound and vibration propagate much more efficiently in water than in air, and the ice layer is an excellent solid medium for transmitting sound, like a giant drum surface."

"If I were to use an axe for high-intensity impact drilling, the immense noise and irregular high-frequency vibrations would transmit almost undiminished through the ice layer to the entire underwater area."

"Fish are extremely sensitive to changes in water pressure and vibration. In the relatively quiet underwater environment of winter, such explosive impacts from above are the highest level danger signal."

He continued analyzing: "The consequences are predictable; the fishing spot would be severely disturbed, and the fish would immediately go into a stress response, fleeing to deeper and farther waters."

"And they would remain highly alert to this area for a long time. A single act of violent drilling could completely ruin a fishing spot I painstakingly scouted, which has long-term value. This approach is not worth the loss."

"Therefore, I plan to use a rotational cutting method to make the hole."

"Continuous, low-frequency cutting of the ice layer with a spiral drill bit produces far less noise and vibration, which is more regular, more like the sound of water flow or the ice layer itself."

"This minimizes interference with the underwater environment, allowing the drilling operation to be completed before the fish enter a large-scale stress response."

So, before stepping onto the ice-sealed river, he had to return to the shelter to complete a task that required higher technical demands.

He turned, his gaze landing on the cold and heavy steel tie rod bolt.

It was time to use fire and iron to forge his tool!

To turn the cold, hard steel tie rod bolt into a tool with a sharp blade, he must first master the power to control metal—sustained high temperatures.

"The open bonfire in the fireplace would let heat escape uncontrollably in all directions. I once used it to melt lead blocks, but lead melts at just over 300 degrees, which was child's play."

"But for steel and iron, to make their molecular structure active enough to be rearranged and combined by external force, or enter a 'plastic' state, the temperature must be raised to at least 800 to 900 degrees Celsius."

"And when it needs to undergo welding or more complex treatment, it even needs to reach 1100 to 1200 degrees Celsius."

"In that temperature range, the steel will emit a bright orange or even near yellow-white glow. To achieve this temperature, wood alone is not enough."

"I need higher calorific value charcoal. And most importantly, a forced air system to inject a massive amount of oxygen into the fuel to catalyze fierce combustion."

His gaze fell on the enormous, orange-yellow Fishery Floating Box beside the shelter.

Today, he would take this abandoned waste product and start his "Industrial Revolution," taking the first step in making a bellows.

The complexity of this project far surpassed any creation before it, and Lin Yu'an knew it would take at least an entire day and absolute focus and precise execution.

But his first task today was not to start making the bellows directly, but to first prepare a forge capable of bearing and concentrating high temperatures.

He would not start from scratch; his gaze turned to the rectangular stone trough outside the wall of the shelter, which he had built over ten days ago for mass roasting mussels.

That structure, built from flat stone slabs, was blackened by smoke but still sturdy after multiple uses.

This ready-made stone trough saved him a lot of initial work. But the structure used for roasting seafood still fell short of the heat resistance and heat-gathering performance needed for metal forging and required a thorough transformation.

He turned toward the back of the shelter, where there was a snow-covered mound of earth, the soil he had piled up when he dug the cellar. He used the back of the axe to break the frozen surface, revealing the loose dark soil beneath.

He took out an iron bucket he had found by the sea, filled it with soil, and returned to the shelter.

He then mixed the soil with water, adding some chopped dry grass as reinforcing fiber, and began kneading and pounding it repeatedly until they became a viscous and uniform "mudbrick clay."

Next, he began upgrading the old stone trough by carefully filling all the gaps between the stones with this homemade "mudbrick clay," like a mason.

He pressed the clay firmly into each gap with his fingers, ensuring the bottom and sides of the entire stone trough were completely airtight, preventing a single precious bit of heat from escaping through the stone crevices.

To further enhance thermal insulation, he applied a thick layer of clay on the trough's inner walls, forming an initial smooth refractory layer.

After completing these basic modifications, he did not stop.

His gaze turned towards the stack of stone slabs meticulously sorted and piled by the wall of the shelter. These slabs, discovered during his exploration of the riverbed, are distinctly different from the surrounding common granite.

He extracted a few slabs with a bluish-gray color, their surfaces exuding a peculiar soap-like texture.

"Sometimes, an inadvertent discovery can prove useful at the most critical moments." He rubbed the surface of the slabs with his fingers, feeling the unique, wax-like texture.

He explained to the camera: "This is soapstone. When I found them, I originally planned to make a BBQ stone slab because they conduct heat very evenly, unlike ordinary stones that can crack due to sudden temperature changes."

"Its main component is talc, although not very hard, but it possesses two crucial characteristics needed for any forge—extremely high heat resistance and excellent thermal capacity."

"It can withstand temperatures over a thousand degrees without cracking and can, like a battery, store heat and radiate it slowly. Now it seems its true mission is not cooking food, but creating tools."

What he needed was a more precise internal upgrade, to install a professional high-temperature-resistant lining for this ordinary stone furnace bed.

Lin Yu'an first cut off a sleeve from an abandoned T-shirt, wet it slightly, and made a simple dust mask, then took out the frame saw to start cutting these soapstone slabs.

Soapstone's hardness is not high, making processing relatively easy, but cutting generates a lot of fine talc-like dust that is harmful if inhaled into the lungs.

He purposely chose a position where the wind would carry the dust away and made sure to protect his mouth and nose.

In the next few hours, Lin Yu'an shaped them into standard rectangles and trapezoids that could perfectly fit into the stone groove.

Then he tightly adhered a large, cut soapstone slab to the bottom of the stone groove, and meticulously lined the inner walls on both sides with smaller pieces.

He used homemade clay mud to carefully fill each gap between the soapstone slabs, ensuring the entire lining formed an airtight, highly cohesive structure.

After completing all this, the inside of the stone groove was completely covered with a layer of smooth, dense bluish-gray soapstone.

He dusted his hands off contentedly, saying, "In this way, the flames and peak heat will be entirely absorbed and reflected by the internal soapstone lining."

"The outer layer of ordinary stones now only serves structural support and secondary insulation. The temperature transferred to them will be significantly reduced, eliminating the risk of them cracking or exploding due to overheating."

A forge composed of the external structure of ordinary stone, a soil sealing layer, and a soapstone fireproof lining was now fully completed.

He then used a soapstone slab to cover the top of the forge as a removable lid.

This main lid did not completely cover the stone groove, leaving some space at both ends.

At one end of the stone groove, he left a rectangular operation port for future additions of charcoal and insertion of steel.

On the other end, he arranged a smaller slab of soapstone diagonally, forming a downward adjustable air inlet, where the nozzle of a bellows would be inserted, with a third slab placed nearby.

He demonstrated to the camera: "The core of this design is controllability. During heating, I can cover most of the operation port with the spare slab, leaving only a slit to observe the color of the steel, maximizing heat retention."

"When needing to add fuel or operate the steel, the cover can be removed at any time. It's simple, efficient, and absolutely safe."

Once he completed all this, the originally simplistic stone groove for cooking had transformed into a structurally reliable, highly heat-efficient professional horizontal forge.

It lay silent there, waiting to be assigned a new mission by fire and steel!

But merely having a burner was not enough to ignite flames capable of smelting steel.

He required fuel with a higher calorific value, and the first thought he had—and currently the only feasible solution—was charcoal.

Lin Yu'an demonstrated to the camera with a burning stick: "When wood burns, the yellow and orange parts of the flame mainly come from the volatile substances in the wood, like wood gas burning, dispersing heat and lacking concentration."

"The true provider of high temperature is the bottom parts that are glowing red, already carbonized. The key to making charcoal is to pre-remove all these volatile substances, leaving only the purest carbon."

"Its ignition point is higher, has no open flame when burned, but releases stable and concentrated radiant heat far exceeding that of firewood."

Without the conditions for digging into the frozen soil to construct an earth kiln, his gaze eventually fell upon the metal barrel he had dragged back from the coastline.

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(00:00 two more updates to come, 7000 words.)

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