After re-reading this thread, and Roger’s new article linked above, I’m at quite a disadvantage not having the technical know-how involved. Nevertheless, the D-P fabrics do not seem to have the qualities desired for a lightweight pack. They are heavier, stiff, and appear to present issues involving creasing and resulting wear and possible leakage.
I’ve found that woven pack fabrics with a softer hand work better for packs in a variety of ways, including drawstring closures mentioned above. Although the next MYOG pack will have a covered WP zip closure, I’ve noted, for example, that fabrics with a softer hand zip a lot more easily. In 2007, I made a pack using “White Widow” nylon pack fabric from Seattle Fabrics in a spruce green color. The riptstop yarn is Spectra, and I’ve seen a similar material recently on the Extrem Textil site. That pack has weathered many multi-week treks, including long bushwhacks, and has not even a scratch. Unfortunately, it is a on the heavy side, ~5 oz/s/y, and the PU inside coating, while showing no signs of damage, seems to have thinned a bit, raising some doubts about continuing waterproofness. The more recent Dyneema grid ripstops come around 5 oz, and lighter, like one offered by Thru-Hiker. But their coatings appear less robust, raising similar questions about waterproofness.
In 2013, Rockywoods offered a 210 denier, double ripstop sand colored nylon pack fabric weighing ~3.5 oz. (Part # 1987-134), specially made for the US military, which found it below spec. The PU coating is substantial, but has a slightly waxy feel, which may have been the problem. In any event, the double ripstop greatly improves the durability, and the waxy feel of the coat does not appear to affect the waterproofness. This is what will go into the next pack, with a butterfly frame of Easton ALU tent pole tube that was kindly pre-curved by Roger Caffin using his home-made “Rolling Jenny.”
One requirement of SUL gear is a lot of TLC, excluding baggage racks and the like. This is no problem, since I enjoy driving long distances, bringing along a couple pups who I’d never consign to a crate in a baggage hold. NH to Colorado is a great ride, seeing America (like in the Simon & Garfunkel song).
So will wait a few years to see what develops in pack fabrics, and then maybe ask Richard Nisley about submitting a few more samples.