Julian left the dorm with a broad grin while the twins got dressed and ready to follow. About ten minutes later they came down into the common room in their usual school robes, and his smile flattened into a frown.
"The first thing you need to know about working around fire," he said, lifting his wand, "is this."
With a quick flick, their clothes shifted, transfiguring into sturdier, close fitting versions of his own jeans and shirt, adjusted for their size.
"Never wear loose fabric that can flap about or catch fire," he finished, tone serious.
Both of them nodded immediately. It did not take much imagination to understand how badly that could end.
...
"So," Julian said, grin returning, "did you both have a pleasant night's sleep?"
The twins snorted.
"You got us good, we admit," one said grandly, "but know that we shall have our vengeance."
Julian laughed. "As long as you keep it out of my workshop, I have no problem with that."
With that settled, he turned and led the way out of the common room. The workshop was only a short walk down the corridor from the Fat Lady's portrait, so they reached it in under a minute.
...
Julian unlocked the door and stepped inside, giving the room a quick visual sweep. Nothing seemed out of place at first glance.
Cannot risk assuming, he thought, and let his magical senses flare outward.
This time, he picked up a faint disturbance. It was a small, almost insignificant thread of magic clinging to the furnace, but the unpleasant, oily edge to it told him everything he needed to know about where it came from.
Feeling threatened, are we, Voldemort? he thought, a touch of grim amusement in his mind.
He focused on the spell, isolated its structure, then stripped it apart with a precisely tuned "Finite Incantatem," directing the counter directly into the hex.
Its purpose had been simple and nasty. Once the furnace reached a specific temperature, the enchantment would have forced it to explode outward, likely killing or maiming whoever was standing nearby.
So he wants to avoid attacking me openly for some reason, Julian decided coldly. Fine. If he prefers games, I can play those too.
...
He turned away from the now cleansed furnace and lit it with a word, switching the internal flame over to dragon fire using the dial.
He did not immediately crank the heat. Instead, he let it warm gradually.
"Best to let the furnace come up to temperature slowly before you really push it," he explained to the twins. "It helps extend its life. Even something as tough as this will wear out faster if you abuse it every time you use it."
All tools, no matter how durable, reached the end of their life eventually. There was no sense hastening that if it could be avoided.
Julian moved to the stack of rough metal ingots against the wall. They were usable for storage, but not for forging anything serious. In their current state they were full of internal flaws and would make weak, brittle pieces.
He left them where they were and instead grabbed one of the long bars of dragon steel. With it in hand, he returned to the furnace and nudged the temperature dial higher. The dragon fire responded immediately, and the room's temperature climbed sharply.
Sweat started to bead on the twins' foreheads. They silently thanked him for changing their robes into more sensible work clothes.
Julian, by comparison, only had the faintest sheen of moisture on his skin, his natural heat resistance showing as he opened the furnace door and slipped the metal bar inside.
He twisted the centralization dial, and most of the ambient heat disappeared at once, funneled inward into the furnace chamber itself.
While he waited for the metal to soften fully, he continued the lesson.
"Yesterday I was only breaking down and folding scrap," he said. "Today, I want specific amounts of clean metal for proper work. Liquifying it lets me separate exactly how much I need, and whatever remains can be shaped in a mold into a new ingot. Two jobs finished at once."
Doing this for every piece of metal he owned was going to take far longer than hammering rough junk flat, but it was far more efficient in the long term.
Fortunately, dragon fire did not take its time.
By the point Julian finished speaking, the bar inside the furnace had turned into a bubbling, molten mass.
...
He opened the furnace door. Liquid metal started to slosh toward the edge, but he caught it before it could spill, guiding the glowing substance into the air with his wand.
The molten dragon steel gathered into a bright, hovering orb, every flicker of its surface shining like miniature sunlight.
He directed most of that mass into a waiting mold on the floor, letting it flow in a steady stream. A smaller portion, about the size of his thumb, he separated and held aside.
"When this cools to the point that it is mostly solid, I will start shaping it," he said. "Any questions while we wait?"
"Yeah," one of the twins asked, pointing with his chin toward the corner where rarer metals rested. "Why are you using that stuff instead of the really fancy ones over there?"
Julian snorted. "Feels like a waste to make a ring out of the best metals I own when its only job is to keep slugs off vegetables," he said honestly.