Abstract: A method and apparatus for forming an insulation blanket adapted for use in the accelerated curing of prestressed concrete is disclosed. Sets of feed rollers are positioned in equal numbers on opposite sides of a take-up drum. The feed rollers of each set carry a vinyl material forming an outer layer of said blanket. Each roller of said set is offet relative to the adjacent rollers so that the ends thereof overlap with respect to the adjacent rollers. An insulation feed roller feeds a heavy insulation medium layer onto the take-up drum. Equal numbers of sets of said feed rollers apply said vinyl outer layer to opposite sides of said medium layer. Adhesive is applied to each feed roller as the vinyl outer layer leaves said feed roller, providing means for joining the vinyl materials together and to the medium layer.