So… been lurking here for over a month and am finally ready to make my own backpack. But, for two weeks, I've been combing forums and websites to find the right answer to this final question.
I've built a model of the backpack I intend to make, but am a little ambivalent about choice of material for the body of the pack. I already have some 1000 Denier Cordura I'll be using for the back and bottom of the pack, so the material I want doesn't have to be quite as tough, but I don't want something that is going to last me just one thru-hike, either.
I think I've narrowed it down to these four materials and would love some advice from you DIY-ers out there with practical knowledge of them.
Here's what I'm considering, in order of current preference.
Grey VX-21 XPAC (from Rockywoods)
White Widow Spectra (from Seattle Fabrics)
300×400 Diamond Ripstop (from Rockywoods or Seattle Fabrics)
Dyneema X (from Thru-hiker)
The weights for all for of these are about 6oz/sq. yd. (except the Dyneema X, which is about 4oz/sq.yd.), so I can't really weed any of these out due to weight.
The VX-21 and Dyneema X are about 200 denier, while the 400×300 Diamond ripstop and White Widow are 300/400 and 500 denier respectively. But is denier actually helpful in ascertaining abrasion resistance? Or is it really only useful in gauging actual thickness of the material?
And then there's also the discussion of ripstop vs. smooth-faced cloth.
If the Dyneema X is only 200 denier and possesses raised threads comprising the ripstop "grid", does that make the difference in durability even greater than the difference in denier would suggest in comparison with the smoother 500 denier White Widow?
Not sure this question really vexes me anymore, though. All four of these materials are some sort of ripstop fabric, so the answer may me be moot for me.
It seems that the VX-21 definitely wins out in regards to waterproofing, but reading about the dangers of sewing mistakes being problematic with the laminate structure of the material makes me a little wary of it.
I'm really leaning towards VX-21 because of its stiffness and waterproofness. Plus, the packs I've seen in these forums made from XPAC look amazing. But, its lower 200 denier makes me wonder how rugged it really is. Plus, I am certainly not an experienced sewer. I don't want to buy this fabric and then promptly destroy it's ability to shed water with repeated mistakes, ya know? I'm not silly enough to believe I am not going to make mistakes in this project.
I love the look of the White Widow Spectra, and with its higher denier,I think it would likely be a good material. But I've found almost no info on this material, so I'm not quite sold on it. Especially considering its price is 70% more than the VX-21.
As for the other two possibilities… the Dyneema X seems to be used often in many quality packs. And honestly, it comes up in nearly every discussion like this, so I thought it prudent to consider it. But, is it really so amazing? Or has it just been used so much that it's used reflexively for it's distinct appearance and because it's instantly recognizable?
The 300×400 Diamond Ripstop, I think, looks pretty interesting (plus I had an old Kelty pack that was comprised of something similar that really held up well). But, as with the White Widow, I can't seem to find any real info on this material. Anyone have any practical experience with this material?
I'm looking to make a sub 2.5lb pack that's about 40-50L (at least, that's what volume my model ended up being). I want something that is lightweight (which, to me, all these qualify as), but holds up well to constant use. Waterproof would be awesome, but it ain't a deal breaker. Mostly, I just want it to work well and last more than a year.
Sorry about the long post… I feel like searching the internet for answers has only complicated matters for me. I think my brain's full.
So, any advice at all would be very helpful.
Thank you.

