Does X-Pac really offer weight & performance benefits over Cordura?

[Roger Caffin]

I have a summer pack and a winter pack. Both use waterproof X-Pac fabrics with taped seams, which nominally mean they are waterproof.

Things like clothing go into good plastic bags inside silnylon bags for two extra layers of WP. Down gear goes into a Pertec stuff sack inside a plas bag inside a silnylon bag. If necessary I put a silnylon pack cover or poncho over the pack itself.

Paranoia? Maybe, but water is still out to get you! And I have never had wet gear. Wet me and wet worn clothing – it happens all the time. But I KNOW we have a warm dry change for when the tent is up and we are inside.

Cheers

[Sam Farrington]

“… water is still out to get you!”

It is a puzzle why my MYOG packs are reliably WP without using various plastic bags?
Certainly we have enough drenching rain here. Some of the fabrics I’ve used are:
– White widow spruce green 4 oz nylon with Spectra gridstop and PU coat – no longer sold by Seattle Fabrics. Some of their current fabrics are interesting, but come only in black.  Extrem Textil used to have what appeared to be the same fabric (Product # 71359), with a small square grid, but not anymore.  RBTR also has a similar fabric, but does not spec the HH.  https://ripstopbytheroll.com/collections/waterproof-nylon-fabric/products/210d-hdpe-gridstop            Their robic is 6 oz+, but again, no HH spec.  Ditto, Thru-Hiker.

– Rockywoods #97-134. desert tan 210D, 3.7 oz ripstop nylon with PU coat, but sold out.
They have something similar in black, http://www.rockywoods.com/210-Denier-Doublewall-Ripstop-Nylon-Polyurethane-DWR-Black

– OWF used to have a WP tan under 5 oz ripstop with a plastic coat of unknown composition, maybe vinyl but no DWR. Textron spray provided the DWR. It was very WP, but they no longer have it.

Also seal my packs both during and after sewing, but think I’ve answered my question – there is not much MYOG-worthy out there these days except DP laminates.
Although RBTR has a polyester, Hyper D 300D, 3.9 oz, diamond ripstop that boasts a 4000 HH PU coat, in many colors: https://ripstopbytheroll.com/products/hyperd-300-diamond-ripstop-polyester. Polyester, but might be worth considering.
There are super K coated taffetas from Extrem Textil and maybe Rockywoods under 5 oz, but they are stiff and have no ripstop grid.

Will look around and keep an eye out, and post anything else that looks promising on this thread. Have enough of the above discontinued nylon stuff for a couple packs.  After that guess it’s going to be DP laminates, sewn, and then taped as Roger suggests.

Could make a list of the smaller items in the pack that also need WP protection, but everyone’s kit & organization is different, so it would probably not be helpful.

[Geoff Caplan]

Hey, Roger is even more paranoid than I am! But he makes a good point – protecting your safety-critical gear from water is surely worth a little inconvenience and a few grams of weight. Would any of us really trust the pack alone without backup? Just imagine hitting a cold, damp camp and discovering that your down gear is sodden… And we tend to dismiss pack covers, but you could make something feather-light out of cuben or RSBTR membrane which would add an extra layer and keep the face fabric from absorbing water. I use front pockets, so I could do this and still have access to my gear. I might try it.

Sam, something that strikes me about many of the alternatives to Cordura. With X-Pac, the HDPE gridstops and all the other nylon options, it’s rarely clear whether you’re being offered nylon 6 or 6.6. There’s a substantial difference in durability, so this quite a big deal. The weave can make a big difference too, and this is a lottery with the alternatives. With a proper branded Cordura you are assured of nylon 6.6 with a proven weave. Many Corduras are also to military spec MIL-C-43734D, which guarantees decent HH (along with many other performance metrics). Something to be said for standards for such a critical part of your gear.

[Roger Caffin]

Actually, I normally use my silnylon poncho as the pack cover (ie over me and the pack). See MYOG article at
https://backpackinglight.com/myog_mntn_poncho/

The advantage is that I don’t get a sweaty back like you do with a jacket (any jacket) when going uphill. Plus, with an open-down-the-front poncho, I can control my heating to a very fine degree. It even works in the snow.

Col du Bresson, France

Dual use!

Cheers

[Geoff Caplan]

Roger, I really like your mountain poncho design – I’d be using it if I wasn’t committed to the Aarn front pockets concept.

Aarn himself worked with Packa to come up with a solution, but that way madness lies – they seem to have dropped it.

Ah well, you can’t have everything…

[Paul McLaughlin]

Geoff – having made a poncho based on Roger`s pattern, with minor adjustments, I think you could pretty easily adapt it to accomodate the front packs. It would probably require anextra seam or two and some mockup work, but ought to work just fine.

[Roger Caffin]

I have tested an Aarn pack with front pockets, and for myself did not like it. The pack was designed for someone with a much longer toso than I have, and the front pockets prevented me from seeing where my feet were going. Well, that’s me.

But, I cannot see why my poncho design could not be modified just slightly to fit over an Aarn pack with front pockets. You would need to make the front section just a bit bigger. Think along the lines of modifying it for an over-weight Dolly Parton (with pack).

Cheers

[Geoff Caplan]

Roger

I’ve played around with a poncho jacket, but the problem is that it covers the gap between the pockets and you can’t see your feet. I mucked around with ideas to shape it a bit and get the Dolly Parton effect, but that restricted the air flow which rather defeats the object. And it also restricts access to the front pockets themselves, which I use to carry water, navigation, on-trail clothing etc. So not really viable.

I don’t sweat all that badly, and find I can get by with a conventional jacket with good venting.

[Sam C]

I am a myog’er and have a preference for Cordura followed by packcloth and oxford.  For one, their durability and waterproofness, whatever it may be, are fine for my needs.  I am another who also uses plastic bags for a liner and also for use as dry bags if needed (zip-lock bags).  I am also not an ultralighter and I don’t think in terms of weight penalties.  I am simply a lightweight backpacker/hiker and if I really were to fuss about the extra few ounces of 1000D Cordura in relation to my overall pack weight then I’ll just simply remove my GoPro, tripod, and attachment to turn a trekking pole into a selfie stick from my list.  Just kidding, I don’t own any of those.  Still, not an issue for me.

I also like those three fabrics because they can be found in an array of basic, solid, colors and in a plain weave.  Sure, you can find X-Pac with a plain, non-ripstop grid, face but this option does not seem available for all deniers.

With that, the main reason for why I have yet to build a pack with X-Pac is from reports a few years ago of the fabric suffering from delimitation issues and with some reports that it is not as abrasion resistant as one may think, although I do not recall at what denier, yet VX-21 keeps coming to mind.  At least Cordura has withstood the test of time (since the 1930s, I believe) and you generally know what you are getting with it.

[Roger Caffin]

Hi Geoff

You really should READ my MYOG article on the poncho. A KEY feature of my design is that the front is split right down, all the way, so you can push the poncho back over your shoulders if you want. Many’s the time we have had the poncho on our packs (like a Packa) for much of the day, but not over our bodies – except for the frequent 15 minute downpours.

Cheers

 

[Sam Farrington]

Would not try to differ with Roger about fabrics, but do not like to feel suffocated or confined when packing in the rain. Am wedded to Patagonia shells, currently an M-10, preceded by a Specter.  The M-10 breathes better, but does not cover my nethers as well as the Specter did.  Neither ever leaked.   All my MYOG packs have suspended mesh backbands, and they breathe quite nicely, thank you.   Here’s a pic of one currently under construction and revision:

On the lower right you can see through the mesh to the inner back panel, unzipped and pushed to the side.  The WP zips add too much weight and will be removed, with a new lighter but even more WP inner panel sewn and sealed in place.  The hubbed frame will be replaced by an hourglass frame of prebent Easton 340 tube, and will be both lighter and stronger in order to hold the belt (not shown) firmly against the hips when cinched tight.  The inner back panel prevents any rain coming through the outer mesh back panel from getting into the pack.

Not sure about the pessimism about my WP packs.  Other than doubts about my seam sealing, maybe it is because so many have bought the marketed stuff and been burned – soaked, that is.  Ditto, for the DP laminates.  But won’t preach to nonbelievers, though water proofing is one area where MYOG really shines, because we can choose the best materials and construction that the manufacturers do not provide.  Just one advice, if the BP trip also includes long days on big lakes, be sure to get a super WP spray skirt, and have a chin strap on the hat or cap; otherwise when the the wind blows the hat away, and you can’t let go of the paddle without the kayak rolling over into the drink,  the resulting burn will be truly worse than anything that can happen in a pack shop.

[Roger Caffin]

For what it is worth: my red packs are made from light VX-series X-Pac fabrics, and were waterproof for many years. However, the lid of my summer pack, which has had an awful lot of use (months at a time in Europe for instance), has started to suffer delamination.

I am told by the DP rep that the fabric was from a very early lot (I had the lot number still), shortly after they started production, and that the bonding has improved since then. And also that the bonding on the new fabrics is significantly better again.

We all like UL gear, but I think we need to acknowledge that it may not last as long as ye olde 12 oz canvas. I have been happy with the trade-off as I have seen it.

Cheers

[Sam Farrington]

A couple additional comments:

I’ve tried Cordura labelled fabrics, from 1.3 oz Cordura silnylon up to 10D PU coated nylon. They all had a tendency to leak, some sooner, some later. My pack for about ten years was a modiifed Jansport internal frame, medium weight Cordura fabric pack, and after hard use over a number of years, the PU coating failed; but before that, no leaks and the fabric never ripped or weakened. Due to the weight, would not use it again. I think the heavier Cordura is close to bombproof, but as has been already noted, the WP will fail, so plastic inner sacks and/or a pack cover are needed. Note that McNett SeamGrip makes a product to recoat PU tent floors, called TentSure, that might enhance and prolong the PU coat.
I think there are <5 0z nylon pack fabrics available today that are reliably waterproof, and will produce a WP nylon pack unless it is going to be bushwhacked through thorny patches. May be a dinosaur, but these are what I use today to make nylon packs that are truly suited for light backpacking.

And a partly rhetorical question: If it is not possible to make a light waterproof pack of nylon fabric, then how is it that nylon tents are being made of much lighter nylon fabrics that are reliably WP and hold up in severe rain and hail storms despite the wear and tear on floors and outer walls by hikers and their pets?

Also, after following fabric testing here and elsewhere, it seems that 6,6 nylon is a Dupont product intended for recreational use, and there is nothing unique about it. Suspect that it is probably made in Asia nowadays, as are other nylons that are just as durable. And there is no guarantee that Dupont 6,6 nylons or any other will be highly WP. Nor that representations of WP from merchants can always be trusted. I was informed by a popular online dealer in writing that a pack fabric was rated at over 4000mm HH, and later discovered from tests posted by Richard Nisley on BPL that it was around 1000mm HH, which is not reliably WP. Note that some of the vendors, like Rockywoods and RBTR publish strength tests on their sites. It is a great thing that we have had Richard’s guidance on BPL; otherwise, MYOG would be a total crapshoot.

[Roger Caffin]

Hi Sam

Packs vs tents: a good Q.
Part of the answer is that tent fabrics yield under impact from raindrops, while on a pack the fabric can not yield. This means that the pressure on the tent fabric under rain is far less than on a pack. You need very high-speed filming to record the inside of a tent fabric under these conditions, and I do not have the facilities. But with lots of searching you can find research papers on it. With very heavy drops you get momentary ‘dimples’ being formed.

Tent roof vs tent floor: indeed.
The HH requirements for the floor would seem to be much higher at first glance, but sometimes it does not work that way. You know your tent roof will get hit by high speed rain drops, but just how wet will the underside of your tent floor get? To be sure, sometimes it can get very wet – like when my tent floor was floating in 4″ of flooding rain one night. But we were sitting on our air mats at the time, so the HH exerted on the floor fabric was actually quite low.

On the other hand, if you poke sticks or thorns through your tent floor … you get what you deserve.

Now, is nylon 6,6 made only by Dupont? I really, really doubt this. I have never seen any hint of it. Rather, what I have seen suggests that Asia makes its own. The recipe is quite well known after all. Perhaps Dupont once held a patent on it? Maybe. If I am wrong (always possible), please let me know.

Edit: yes, Dupont did once have a patent on a method for the production of nylon 6,6, but I believe they have since sold it. Anyhow, patents expire.

Cheers

[Geoff Caplan]

Sam

Nylon 6 and Nylon 6,6 are different polyamides.

https://oecotextiles.wordpress.com/2012/06/05/nylon-6-and-nylon-66/gg

In fabrics, the 6,6 is considerable stronger, but also more expensive. Check out the difference between the RSBTR standard and MTN silnylons, for example – the MTN is much superior, but at a premium price point. For durability, you could expect a 6.6 to outperform a 6 of the same weight by a considerable margin.

Of course the base polyamide tells us nothing about the quality of the WP coating. Many Corduras are certified waterproof to military standards, though of course they do degrade as you say. On the other hand, I suspect that the film in the laminates will degrade too, so I wonder how much there really is in it. With the Cordura, you do always have the option of re-coating as you point out, though as I find the leakage to be a minor issue I’ve never bothered trying.

As for the non-branded fabrics, it’s a crap shoot as you say. Even with Richard’s heroic efforts with the testing, I’ve been told by insiders that there’s a lot of variation from batch to batch which is why Ron Bell has invested in in-house testing.

Rodger –

As for the Mountain Poncho – do please keep calm :-). I do realise I could access the front pockets through the zip, at the cost of some faff and getting a bit wet. And the ability to pull it on and off on the hoof is a killer advantage on showery days. But the key problem is the safety issue of being able to see my feet. I’m tweaking the design of the Aarn pockets to get around some irritations, and it may be I can work in something to overcome the visibility problem with a poncho. But so far I haven’t found anything workable, and as I get on pretty fine with a conventional jacket, I haven’t given it much priority.

[Roger Caffin]

Me, staying calm? Never! No fun guy! :)

Seriously, we have never found the front closure on our ponchos to be any problem. We do not have zips there: instead we have plastic snaps with a velcro cover flap.

Using snaps turned out to be a brilliant move, as it lets us close the middle two snaps, keeping the poncho sort-of around our body but leaving both top and bottom parts of the closure wide open for ventilation. We would travel like this far more often than with the front fully closed.

Most times we don’t use the sleeves either, unless we are climbing in really bad weather. There can be condensation inside the sleeves when the rain is very cold IF we have our arms in them. But with our arms crossed over our body in front inside the poncho we are usually quite warm.

Seeing feet – yeah, big problem with the Aarn packs. I couldn’t see a solution, and gave up.

Cheers

[nunatak]

I have observed X-Pac delaminate fairly quickly, especially on day packs that see so much more use than a backpacking pack.

The VX07 below is on pack used for a year.

[Sam Farrington]

An interesting article linked by Geoff, indicating the differing composition of nylons.  Thank you.
My introduction to 6,6 was via the Thru-Hiker website, followed later by RBTR’s Mountain 6,6. The latter is visibly more durable than the former. Since the 6,6 refers to the composition of the yarn, the difference could involve a number of factors, including the denier (weight) of the yarn. And where does Robic fit in this picture? In short, I don’t think that getting down into the weeds is going to tell us much more than obtaining swatches of materials and testing them. Sometimes fairly primitive tests are enough to rule out some fabrics, which is why I’ve never asked Richard to test a fabric unless such tests first at least suggested a winner.

And it seems we both agree that WP is a different matter altogether.
Most convincing for me is the actual performance of a fabric in the field, so when a pack of that fabric keeps everything inside dry in heavy rain, and continues to do so for years, I’m comfortable without wrapping the contents with plastic wraps. Heresy perhaps, but it works.

Granted, we also have to look at durability. It’s just that if a fabric measures up to the kind of packing I do, that is enough for me. For those clambering among pointy crags and walls, or bushwhacking in high, prickly growth, more durability is required. But since I often solo with a couple of canines to care for, or go with friends, risk taking is not my bag. Safety insures a relaxing and rewarding BP with less likelihood of having to pull out the PLB and drag SAR into the bush. That goes double when my companions are human and share these sentiments.

Roger, I’m sure you give your MYOG tents all the care they deserve; however the occupants of tents, including young ones and pets, can do a number on the inner surface of tent floors, and sometimes time and terrain do not allow for adequate protection of the floor bottom. And there are parts of a canopy surface, such as those near poles or the ground, that will offer resistance and create wear and tear to abrasive attack from even myself being careless, or from a falling limb. My point was that we build WP tents that survive wear and tear for quite some time without leaking, and so ought to be able to achieve the same goal with heavier nylon pack fabrics.

Getting right down to it, I suppose it is the kind of BP we practice that determines the ruggedness required, and therefore the weight of our packs. Each to their own.

[Roger Caffin]

Yep, each to his own.
Although arguing about gear from the comfort of home is such fun!

Yes, tent floors do get hammered. By blue tent has had one complete silicone recoat on the underside – on a hotel balcony in Italy one year. That did work very excellently. (Refuges in the mountains, small hotels in the villages in the valleys.)

Cheers

[Geoff Caplan]

Roger – we’ve discussed the Aarns before. You had issues that most users don’t experience (or they wouldn’t have so many loyal customers!). I can only assume you had some kind of fitting problem.

I have no issue at all seeing my feet, but the poncho would cover the gap between the front pockets and block the view.  I don’t think there’s any practical away around that, short of adding the “boobs” in the Aarn protype above – it’s all too much faff as well as looking excruciatingly silly.

I’ve got a good wicking system and find I’m comfortable in a well vented conventional jacket. So unless I have some kind of brilliant design inspiration I suspect that I’ll settle for that. I experience such dramatic benefits from the Aarn bodypack concept that I’m happy to put up with any small inconveniences that result.

[Roger Caffin]

@Geoff

If it fits OK, wear it. No problems.

Cheers

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