An aluminum mullion and method for creation by an extrusion and castellation process for use in a construction section. The aluminum mullion may comprise a first end, a second end having a guide track; a height, and a mullion body positioned between the first end and the second end. The aluminum mullion may be extruded by pushing semi-molten aluminum through a steel die under high pressure to create a monolithic beam shape and then at least one portion of the mullion body is removed by the castellation process. Multiple portions of the mullion body may be removed along the height of the mullion as needed for construction requirements.

An aluminum mullion and method for creation by an extrusion and castellation process for use in a construction section. The aluminum mullion may comprise a first end, a second end having a guide track; a height, and a mullion body positioned between the first end and the second end. The aluminum mullion may be extruded by pushing semi-molten aluminum through a steel die under high pressure to create a monolithic beam shape and then at least one portion of the mullion body is removed by the castellation process. Multiple portions of the mullion body may be removed along the height of the mullion as needed for construction requirements.