The furnace is a craftable structure in Stardew Valley that is used to smelt ores and coal in metal bars. It can be made after receiving the blueprint from Clint, the blueprint will become available after you go into the mines. Clint will show up at your door the next morning to give you the blueprint. It takes 5 ore and 1 coal to create a bar of that type.
Crafting the furnace requires the following quantity of items:
|Types of Bars||Amount of Ore||Amount of coal||Smelting Time|
|Copper Bar||5||1||1 Hour|
|Iron Bar||5||1||2 Hours|
|Gold Bar||5||1||5 Hours|
|Iridium Bar||5||1||7+ Hours|
|Refined Quartz||1||1||1.5 Hours|