The Giant Smokestacks That Melt Metal

A cupola furnace looks like a simple industrial chimney, but it is actually a high-powered melting machine. It works by stacking layers of metal, fuel, and air to turn solid iron into liquid.

These towering cylinders are the backbone of iron foundries around the world. Because they can be built in almost any size, from small units to massive thirteen-foot structures, they offer incredible flexibility for metal casting. By continuously adding raw materials to the top, workers can keep the molten metal flowing for days at a time. It is a surprisingly efficient way to transform solid chunks of scrap into precise, molten shapes.