Methods for stabilizing insulation and constructing garments from the insulation are disclosed. Methods include arranging the fibers into a plurality of bundle structures. The fibers may be synthetic fibers. The method may include receiving the bundle structures into bundle channels. The bundle channels are formed by tacks. The bundle channels enable the uniform distribution of the bundle structures prior to stitching quilting stitch lines. Multiple quilting stitch lines are stitched after the bundle structures are uniformly distributed. The quilting stitch lines are orthogonal to the longitudinal axis of the bundle structures. The quilting stitch lines provide lateral as well as longitudinal stabilization of the uniform density of the bundle structures. The distance between the quilting stitch lines may be based on the loft of the fibers and/or a required durability of the garment. The quilting stitch lines are generally horizontal, while the longitudinal axis of the bundle structures are vertical.