attained with similar coating formulas are listed in table 1 below the weight of the coating expressed as a percentage of the weight of the total coated fabric may be from about 15 80 weight preferably from about 50 70 weight and most preferably about 55 65 weight in both materials from table 1 the weight percent of the coating was about 60 65 note that a persistent problem in coating dense fabrics i e with yarn frequencies greater than about 10 u00d7 10 warp u00d7 weft ends per inch is an appearance defect known as u201c window paning u201d window paning may be described as dried coating spanning some of the closed rectangular areas of the fabric defined by a adjacent pairs of warp and weft yarns through the use of a small quantity e g 0 1 0 5 of the coating weight of a suitable defoamer such as dc1500 available from dow corning corporation this problem is alleviated an additional problem associated with fabrics which are post coated is the flattening of the strands during drying and winding this problem has been solved in the warp machine direction using a chain stitch in the knitting process which serves to bundle the warp yarn in a circle this particular effect is augmented when the fabric is heated and the stitching yarn shrinks and tightens about the fiberglass warp yarn through the use of highly twisted yarns in the weft e g from about 1 0 2 5 turns per inch the flatness is minimized even without the benefit of cross machine tension to amplify the effect of twist.