Within the Small World.
Old Feng began refining the alchemy furnaces anew, reinforcing them to ensure they wouldn't explode after only a moment of use. Given Old Dragon’s cultivation level, even if he restrained his aura and did not reveal his true strength, these furnaces could not harm him in the slightest, let alone help him forge the Taixu Emperor Eye.
In the stories, Sun Wukong had to endure forty-nine days of roasting before his Fiery Eyes were forged. Therefore, the furnace could not be too fragile, and the fire used could not be ordinary; otherwise, it would likely be ineffective.
Chapter 751