Abstract: A method and apparatus for applying an elongate continuous adhesive-coated reinforcing material such as a string or tape to the surface of a moving substrate is disclosed. A length of the adhesive-coated reinforcing material is heated in a heating unit to the flow point of the adhesive and is thereafter pressed onto the substrate by the rotatable peripheral surface of a wheel that is mounted for rotation on an axle. The heating unit includes an elongate hollow outlet portion having a generally constant radius of curvature that encourages the softened adhesive to concentrate on the bonding surface of the material. A heat-transferable tube is removably located in the heating unit. The heat transferable tube is easily replaced if it becomes worn or fouled with adhesive. Adhesive that separates from the material as it exits the heating unit is intercepted and applied to the substrate. An axle cover prevents the heated, reinforcing material from contacting and interfering with rotation of the wheel.