After reading about using polyester ripstop for covering material here on the forum I thought I'd give it a try. In my opinion this stuff gets a low score as a covering material. Maybe a 2 out of a possible 10. There might be worst stuff out there but it would be hard to imagine it. While it does go easily around large compound curves it is real difficult to get it to stick around any small radius couner. It absolutly cannot be sanded. Instant, irremovable (is that a word?) fuzz. The final color is somewhat unpredictable. I used a bright blue that turned almost black when it was painted with clear dope. It can be shrunk with a heat gun or monokote iron but it "bags" and "sags" again as soon as the first coat of clear is applied. I can't think of anything good to say for it. Not even the price was all that great.
I'm definately going back to silk. $2.50/yd (36" wide) from Thai Silks for white up to $7.00/yd (45" wide) for some colors and they have lots of colors. That's better than the $17.00/yd for the Brodak light weight silk.