Patent ID: 8272117

Claim:
A method of installing a weather sealable, insulatable window frame assembly in an opening in a wall of a building, comprising: providing a metal frame peripherally around a window sash, said frame having channel-forming, outwardly projecting flanges therearound; placing an insulating, elongated, extrusion block arrangement within said channel formed by said flanges of said metal frame to form a window frame assembly, said extrusion block having an elongated air fin co-extruded therewith; inserting said window frame assembly with said extrusion block arrangement therearound, into said opening in said building wall; inserting a compression rod into a compression rod-receiving channel between said air fin and said extrusion block to compress said air fin against said opening in said building wall and to compress said extrusion block against said metal frame; attaching an energyzable thermoplastic welding wire to the outer periphery of said air fin and to the inner periphery of said extrusion block; and energyzing said welding wire so as to heat and thermoplastically fuse said inner side of said extrusion block and said air fin against their respective adjacent surfaces of said metal frame or said building wall.