John, Thank you for the link to the interview with Henry Shires about TarpTent's not using Cuben material. Very informative, especially coming from an experienced tent maker.
William, re: "Samuel, I'm not sure why you think they have changed to a shinier green. I received a Duplex yesterday :) and it's exactly the same olive drab cuben as previously used by ZPacks. The .74 oz cuben, however, is a darker green"
I've got some of Zpacks' current .74 oz Cuben, as well as their .5 oz they were using a couple years ago. The .5 oz has a relatively flat olive finish. The new .76 oz is quite reflective, or shiny. I looked at their website picture of the .5 oz and it appeared to be as reflective as the new .76 oz, but that doesn't appear to be so from your comment. So, it seems I should not have relied on the internet photo. To confuse matters further, the new .76 oz material I just ordered is NOT a dark green, but much more like the light emerald color of my jasmine green Forester.
Was looking at all this, because was planning to test some adhesives on Cuben and am finding that there may be a lot of different Cuben layups out there. So, I thought that testing adhesives on Cuben from Zpacks would be the most helpful to others, because that is a material that is very readily available to fellow MYOGers.
I also have some .76 oz green Cuben purchased a few years ago from Cubic Tech. The label on it indicated it was made differently from what was ordered and stated on the invoice. Tried some adhesives with this material, and the adhesion was strong enough to rip the outer film off the inner fibers, unlike the Cuben sold by Quest, which does not bond well to the same adhesives. So don't really know what the dickens I've got there, so feedback on BPL about Cuben isn't much help in deciding whether to use it.
My point - at last - is that it's looking very much like there may be different Cubens out there. Not just the different ones published by Cubic Tech, but with films made of different substances and different fibers. The Cuben tent you get from one maker might be made of a material quite different than a tent from another, with quite different qualities. On a positive note, I observed that the film used on the .76 oz material form Zpacks was clearly stronger than that purchased from both CT and Quest. The film on the older stuff could be shredded easily, not so with the new.
Henry Shires' comments on the podcast give me still more pause about Cuben, but on the other hand, weight differences aside, there are reservations about the sagging and water repellent qualities of 30 denier silnylon. With a double wall tent, even if the inner is only mesh, good design can go a long way in addressing sagging and condensation; but for a tent that has substantial portions of single wall canopy, the absence of sagging and reduced condensation become more important considerations.
I want to build a tent much lighter than I have now, and to do that, I've concluded much of the canopy has to be single wall. So that is what makes the Cuben so attractive, in terms of eliminating sagging and reducing the attraction of condensation to the inner surface, and is why I've been experimenting with adhesives to see if nylon strips can be bonded to Cuben at the seam lines in order to address Cuben's issues with holding stitching securely and keeping stitch holes from expanding. (Have tried all the tapes, but won't go into the issues with them now).
The only other alternatives no heavier than 30D silnylon that seem feasible are: 1) coated polyester, which sags very little and absorbs water much less than nylon, or 2) nylon treated to do the same, but not as much. Haven't found any of either so far with good water resistance, with one exception, the coated polyester used on the Snow Peak Lago tent fly, but can't source it for MYOG.
Please forgive me for going on like this. It is the only way I know to explain the difficulties with choice of materials, an issue that affects gear buyers as well as MYOG material buyers.