This fundamental rule of blacksmithing dictates that forging must happen while the workpiece is at its optimal working temperature, typically glowing red or yellow. As the metal cools on the anvil, its crystalline structure stiffens, increasing the risk of cracking and requiring exponentially more physical effort to move. Once the color fades, the smith must return the piece to the forge.
Heard on the job
Stop talking and hit it, you have to strike while the iron is hot or we'll need another heat.
Insider tip
Working iron after it loses its heat is called cold working, which can cause micro-fractures in high-carbon materials.