Below is a list of Copper Coil manufacturers from Downers Grove, Illinois. Copper coil is a thermally and electrically conductive component in many different systems and machinery. It is made of copper wire or tube that is bent and wound into a rounded spiral shape. They are almost always manufactured out of copper that is at least 99.9% pure. Copper is a smooth, shiny, soft and malleable metal that is desired for its formability, chemical resistance, low oxidization rate and its conductive properties.