Abstract: A method of and apparatus for fusion bonding a continuous synthetic thermoplastic resin fastener strip having a fastener profile portion and a base portion opposite the profile, to a continuous film substrate. The substrate is advanced continuously through a bonding zone. Continuous direct transit of the fastener strip is effected from thermoplastic extruder downwardly through a short distance to the bonding zone, so that in the short transit distance the fastener strip will retain substantial residual thermoplastic fusion temperature. The fastener profile portion is chilled while the strip is in transit to the bonding zone, solidified and stabilized, but the base portion is left at sufficient residual fusion temperature to remain thermoplastic to the bonding zone where assembly of the strip and substrate is effected by fusion bonding of the base portion to the substrate.