Heat a propane forge to 1,800 degrees Fahrenheit.
Heat 5 inches at one end of 30 inches of hot-rolled mild steel in the propane forge until it is yellow-white. This color steel shows the steel is heated to 1,800 degrees Fahrenheit. Always wear leather gloves and use tongs to hold the steel.
Hit the yellow-white steel with a ball pein hammer. Begin at the spot where the color changes from brown steel to yellow-white over the thinnest end of the anvil, called the horn.
Continue hitting the steel, bending it into a curled loop until the steel is no longer yellow-white. The steel will remain the correct working temperature for less than 30 seconds.
Reheat the 5-inch end to yellow-white until the entire 5 inches has been curled into a continuous loop.
Dip the heated end of the steel into a bucket of room temperature water to cool the metal.
Repeat the creation of a curled loop on the other end of the steel to form a decorative cast iron curtain rod.