Abstract: The method of forming a lightweight, high performance, glass fiber blanket for acoustical and thermal insulation, that includes treating glass fibers with a fluid binding agent at elevated temperature to form a first cohesive glass fiber layer of thickness t1 traveling endwise, and winding that layer into a roll above a travel zone of that layer, repeating said treating to form a second cohesive glass fiber layer of thickness t2 traveling endwise over said zone below said roll and into an oven, and unrolling said first layer from said roll to travel into the oven in overlying surface to surface contacting relation to the traveling second layer, subjecting said layers to heat treatment and pressurization in the oven to compress the first and second layers to a controlled density thickness t3 which is substantially less than t1 and t2, and to progressively bond said first and second layers together in laminated relation to form the blanket, and removing said laminated product from the oven.