Below is a list of Copper Expanded Metal manufacturers from Trafford, Pennsylvania. Copper expanded metal is a sheet or plate composed of copper or its alloys, such as brass or bronze. It has been slit and stretched simultaneously to create an open framework of solid construction. While many different metals are suitable for metal expansion, copper is chosen particularly for this process when being employed by certain companies, such as those in the electrical, heating and cooling, refrigeration, construction, ornamental and architectural industries.