Air, mixed with gases, is drawn down through the hottest part of the fire. Then secondary air is fed in to aid complete burning. This is the downdraft method. Other stoves use a cross-draft in which air fed in low on one side passes across the burning fuel and exhausts low on the other side. Turbulence over the flames causes the air to mix with the released gases and if temperatures are high enough, the mixture is at least partly burned before it reaches the chimney.
Air passes over the fire and curves back through the flames.
This longer flame path helps burn gases and holds heat in the stove for a longer time. Most modern stoves are made of cast iron, sheet steel, or a combination. Cast iron has properties which make it ideal for stoves. It conducts heat well and is stable through a range of temperatures. Furnace cement is used to reduce air leakage.