Method of and apparatus for using preheated substrate composition

An extrudable material (1), such as a hot melt adhesive, is applied to a substrate (2) with simultaneous irradiation by a laser beam (9). The energy of the laser is absorbed by the adhesive and the substrate to cause the adhesive to spread into the fabric. When applied to a gap (17) between two substrate sheets, the extrudable material creates a very strong bond. When one of the substrate materials (21) is porous, the extrudable material will penetrate the thickness of the material and contact a lower layer (19) to form a bond. The extrudable material is applied through a nozzle, and the laser beam is directed through the nozzle to be coaxial with the flow path (11) of the extrudable material. The coaxial arrangement facilitates movement of the nozzle and beam in complicated patterns and ensures simultaneous application of the extrudable material and the laser beam.