Pack materials for 2018

This post and the follow-up a year later have remained among my most popular works, and with 2018 coming into focus they are at last worth updating.  Not too much has changed in the world of backpack fabrics, but time has allowed for enough clarification that a few things are worth saying again.  There are even some new trends to highlight.

Context matters.  I’ve taken plenty of flack over the years for denigrating trail and thru hiking as a useful design metric for backpacks.  This is a statement I still endorse, but do not mistake holding something up as a metric as equivalent to it being the most frequent or likely use.  Plenty of people get along just fine with fabrics I dislike, and unless you really want to count grams current technology makes producing a good, light, functional trail pack simple.  My own interest has always been, putting the outlier of canyoneering aside, in making and using packs which are as light and functional as the best modern packs, and tough enough for trips like this.

R0010199Nylon ripstop on the Gossamer Gear Type 2 (above) and Osprey Rev 18 (below).  Relatively cheap, certainly light, and for small packs durable for years of reasonable use.  Lighter packs carry lighter loads, can thus usually expect more careful handling, and thus can often get away with lighter fabrics, even if they are used most often.

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Pack fabrics can still be separated into two categories depending upon what waterproof coating they have stuck to their backs.  Polyurethene remains the most common, by far, and provides predictable and in many cases quite satisfactory performance.  The strengths of PU coated fabrics are lower prices, a more supple hand, and a lower amount of weight given over to the coating itself.  The downsides are the eventual degradation of the coating, the fact that most PU fabrics are waterproof to a degree which can be reliably if not commonly exceeded in field conditions, and that applying the coating weakens the fabric.  No one is complaining about the tear strength of something like 330D cordura, but I do believe that attribute of hot-application coatings is why they’re not more liberally applied (which would solve the waterproofing issue).  The quality of PU coating varied drastically, from very good to utter crap, which muddies things for both the home maker and the person just wanting to buy a good pack in the shops.

Laminate fabrics such a hybrid cubens and the various Dimension-Polyant fabrics are the second option.  If I were making a canyoneering pack I’d pick a PU fabric like 1000D cordura without hesitation, as the added weight and waterproofing given by a laminate just doesn’t make sense, especially in the face of no current laminate fabric being adequately durable for such use.  I used several test packs made from X51 (500/1000D cordura) last year, including for this two day excursion and even with careful packing 2 days and five canyons had the X51 on the edge of destruction.  For mountain backpacking, especially outside summer, the added waterproofing and weight of laminate fabrics makes them justifiable.

R0021333Cold and knackered along the Escalante in January.  Canyons beat up packs like little else. Laminate fabrics dedicate a greater percentage of their weights to the waterproofing layer, relative to PU fabrics.  I think the later makes more sense in the desert, for this reason.

Why aren’t many (any?) more commercial packs available in laminate fabrics?  First, the fabrics are more expensive, and needle holes which don’t self heal is I still assume a burden in mass production.  Second, D-P laminates face fabrics they don’t themselves produce in in the US, which means that a Chinese or Korean made cordura would be woven on one side of the Pacific, laminated on another, then shipped back again to be cut and sewn into packs.  Last, and most obviously why the first two hurdles haven’t been overcome, it is more difficult to articulate to the masses how your pack is more waterproof than other supposedly waterproof packs, and yet still is not submersible.  Plenty of people are trying to change these dynamics, and 2018 has the best chance yet of one succeeding.

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Abrasion in 1.3 oz pure cuben (above) and 150D hybrid cuben and VX42 (below).  Pure cuben isn’t reasonable for use in a pack, and the above photo show how easily the strong reinforcing fibers and weak mylar film are easily separated from each other.  The pack below is almost 4 years old, and has been a good test for how the two wear.  The cuben body is fine, but keeping it that way has taken lots of tape and aquaseal.

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Years have only reinforced my conviction that Cuben/DCF is in backpacks mostly hype.  Yes the 150D hybrid is a very good product.  Yes, good packs are made out of it.  But the face fabric itself is still relatively weak in the face of abrasion, and while the laminate itself is without question stronger in every respect than either PU or any PET I’ve seen, using weight and dollars to put strength there continues to not make sense to me.  200-300D nylon face with a thinner cuben film?  Sounds higher performance in every respect.  Since Cuben was purchased by DSM product development and availability has become decidedly less transparent, so while probably the greatest potential resides there in terms of pure pack fabric technology, I don’t expect anything new, one way or the other.

This leaves us with D-P products, which have become more diverse and vastly more widely available.  Rockywoods, for instance, currently sells 10 variants which could be suitable for backpacks, with more commonly available elsewhere.  Much to their credit, D-P has stuck with their fabric nomenclature, which initially seems obtuse but make discussion and differentiation simple.  For our purposes all fabrics have an inner PET laminate (the waterproof part) and an outer woven face fabric.  The V designation means there is an inner fabric laminated to the PET (easily seen by the white inner), while the X designation means the signature x shaped grid of reinforcing fibers is present, laminated within the PET.  Recent trends have gone away from the V layer, something of which I do not generally approve.  In heavier and especially darker face fabrics this results in a very shadowy interior which makes finding things a pain.  In the lighter fabrics, I’m thinking of X21 in particular, the lack of interior scrim takes away a good deal of stiffness, making an already oddly cut prone fabric considerably moreso.  3 years I was already less than fond of VX21, thinking that VX07 punched better given the weight, and that for me VX42 was almost always preferable.  This is not to say that X21 isn’t a good light pack fabric, just that I put it in the sides of a framebag a year ago, and have grown tired of little nicks appearing for no particular reason.

My particular favorites remain the cordura faces on X33 and X50, though VX42 and X42 are very nice.  The slicker face of the 420D plain weave used the latter does very well in brush and sticks, while cordura is better when dragged over rocks.  VX42 has proven difficult enough to put holes in that I’d use it for anything short of the slot canyon abuse shown above, content that I’d be patching holes and nicks infrequently.  X51 ought to be better than X50, but the difference in size between the warp and weft fibers make it a thorough disappointment.  Here my recommendation has not changed in recent years: VX07 for light trail duty, X33 for most things, and VX42 or X50 for abusive applications.

IMG_5567X50 significantly rubbed by 12 miles hauling an elk rack out of the wilderness.  Not overkill in this application.  This also illustrates the way the X grid accelerates abrasion.

A number of areas for improvement are available.  First, more Vspecific fabric options which omit the X grid.  Anyone who has put D-P fabrics to a good test has seen the grid be a major point of abrasion, such that the fabrics would without question last longer without it.  D-P has admitted that branding is at work here, but I also think that packs have become a large enough part of their portfolio that they will shortly be more malleable.   More broadly, it would be swell to see pack fabrics with some manner of durable surface coating that kept them from being saturated under gnarly conditions.  Arc’teryx has done this on a limited basis, so the potential certain exists.

This points to the real future of pack fabrics, which long term is probably in some manner of heavier non-woven.  The woven Dyneema used by Cilogear, HMG, and a few others is impressive, and points towards the way advanced textiles allow traditional fabrics to bend the rules as we know them.  My hope is that fabrics like the Liteskin line from D-P (a non-woven poly face with a woven nylon backer) will out perform traditional fabrics for the same weight, while being less expensive to produce at small and moderate scales than the various dyneema products.

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19 thoughts on “Pack materials for 2018

  1. To the best of my knowledge X42, X51 and maybe X50 can be seam taped, and thus packs could be made submersible (ok, not ‘packs’, but drybags used as packs). Once we have zippers I would not know whether seam taping the pack would make any sense, but there are zipperless top loading rolltops made with those fabrics where the seams are taffeta (I think) bound, not tape sealed. I have seen drybags with zippers designed to be waterproof to 10 metres down in water (apparently they do work), so depending on design and components, fully submersible packs could have been here in circa 2016, or way earlier. I’d pay the extra costs and carry the extra weight, but I do not make the industry go round with my purchases.

    1. Conventional seam tape won’t work on the plain PET film. D-P makes an 07 fabric with a light PU coating on the laminate so it can be seam taped. I imagine anyone willing to pay for a custom run could get that on a different face fabric. One can design a pack such that most stitch lines and seams can either be sealed with Aquaseal or are just really hard for water to penetrate.

      Submersion proof zips are easy, if very expensive. Folks won’t be happy with how much effort they take to manipulate, but as you say there is a demand.

      Porcelain Rocket started making totally welded roll top frame bags late last year, and initial impressions are very good. A welded pack with taping in a few locations might be an interesting way to go.

      1. According to this thread on Backpacking Light (https://backpackinglight.com/forums/topic/new-xpac-colors/) X42/X50/X51 “have a film backing, rather than a polyester taffeta which improves seam taping” (I asked specifically!) though I did not know of the need of a PU film, so that info is/might be wrong. I sealed a X51 pack, but I do find that seam sealing after the fact is a right PITA so I stopped doing it. For years and years I did not quite understand why waterproof packs were not the standard, and everybody I discussed the issue with though I was mad (“what’s wrong with a trash bag inside the pack?”), so I presume for a long while the lack of interest did not motivate finding effective waterproofing approaches.

  2. 3 questions I guess…don’t know if you can help:

    Is the woven dyneema (w/ cuben backing) used by Cilo and HMG as abrasion resistant as they tout? It’s ungodly expensive, but they make it sound almost indestructive.

    Cilo has a X100 on their website…do you know if that’s proprietary or have you seen it for sale?

    Do you have any experience how the Liteskin compares in abrasion resistance to any of the V/X fabrics? I’ve only seen it the TAD bag, and I liked the layout, but it’s an expensive unknown.

    1. The woven dyneema isn’t immortal (I know folks who have put holes in it) but it is a 5 oz fabric whose extremely high abrasion testing figure is born out in the field. You can get equivalent performance by using heavy PU fabrics, so in the end it is a weight savings game.

      I assume Cilo has VX100 or X100 (I think they changed from the former to the later) custom laminated. Again, D-P will laminate any fabric you want if you’ll pay to have enough shipped to them. This was what I had in mind for the SO canyon pack, but it became clear quickly that the extra expense would make such a niche product even more expensive.

      I’ve yet to see Liteskin in person. The heavier version abrasion tests at 2000 cycles, compared to 1500 for X50 and 1700 for X42. The taber tester which generates those numbers is a big sander wheel and is definitely biased towards slicker faced fabrics in a way which is not born out in the field (e.g. X42 testing higher than X50), but it is on my list to take a look at them.

      1. Thank you Dave.

        I didn’t realize it was really a question of weight…the publications make it seem like it’s more abrasion resistant than anything else available.

        You’re right that they are advertising X100 now. I really wish the Canyon Pack would have come to fruition. I tend to always lean toward durability over weight savings…for what I do I’d rather have the long term investment. Plus I’m sure the design would have just been cool.

        I found some tests talking about Liteskin on backpackinglight and the mentioned Taber Test, but what you’re saying is what I’m curious about…how does it actually hold up in the real world.

        1. “I tend to always lean toward durability over weight savings” given how little of the total weight is caused by the choice of fabric when we have a full pack, yours seems to be the only rational approach. Obviously putting 15 litres of gear in a 80 litres pack means a lot of pointless fabric being carried around, but that looks more a matter of pack choice, not construction. In any case, pack weight should not come at the expense of comfort or usability.

  3. Your RSS feed showing this article provided an erroneous link — https://bedrockandparadox.com/2018/01/20/pack-materials-for-2018/ — I tried it and had to use the search function by title to find the correct page. I follow your site via Feedly.

    1. Sorry about that. I failed to update the publish date at first which is why the RSS link isn’t valid. Shouldn’t happen again.

  4. What do you think about TPU-coated Cordura? Heavy, but abrasion resistant and waterproof.
    Like this https://www.extremtextil.de/en/cordura-500den-tpu-coated-hf-weldable-370g-sqm.html

    1. Almost 3 oz/yard heavier than standard PU! I wonder how stiff it is? Might be tough to do corners and so forth.

      1. I think it is better be compared to D-P products in terms of waterproofness, and to 1000d Cordura in terms of abrasion resistance. So, in this point of view it is not so heavy.

        1. Would the TPU increase abrasion resistance to that extent?

        2. Frankly, I don’t have much experience with TPU nylon in person (other than bag in modular saddle-bag). But my outdoor fellows, familiar with TPU fabrics (packraft makers for example) are claiming that it can be true, if TPU layer is outside. Alpackas are made of one-side TPU nylon, so you can make your own valid opinion, i guess.
          I have plans to order custom TPU pack next couple of years, and to use it in corresponding environment, so i hope i will know more.

  5. While I’m hanging out here…what kind of bag do you carry for work? Of course I’m presuming you carry a bag for work, but it would seem likely. Does the obsession carry over?

    1. I’ve gone through a few. For the last couple years it has been an older Mountainsmith Day, as a shoulder bag.

      1. Interesting choice. Thank you.

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