Xpac and Spectra fabrics

I would expect the coating on the X-Pac (PET) to be far superior to the coating on the Spectra or any other nylon (which are usually urethane or PU based)

I’ve had a couple of X-Pac packs that have hard use with no delimination of the coating, but quite a few nylon packs with coatings that have delaminated.

The Flight pack I tested was a prototype with X-21 main body and Spectra pockets.  The Spectra on my pack was uncoated, but I think the production packs use coated Spectra.

I would guess the X-Pac will be more waterproof (and the coating more durable), whereas the Spectra would be the more durable face fabric but the coating wouldn’t be as durable or as waterproof long term.  Pick your priority here: Abrasion resistance vs. Waterproofness.

And I’m just guessing here, but the urethane coating on most nylons  (like 500D cudora or 201d Dyneema grid) seem to be sprayed on or painted on.   The PET layer in X-Pac seems different – I think it is laminated during the manufacturing process.

Delamination – that is what I meant to refer to. That is my concern. I am sure either Seek Outside pack will be durable and waterproof enough for my use. I am pretty good at taking care of my gear, do very little bushwhacking (while backpacking) and usually use a cuben fiber liner for the pack.

Thanks for the feedback.

If you are not concerned about durability, buy whichever is less expensive, or whichever you like the look of better. Spectra grid material is likely going to last longer – the base fabrics are similar, but the spectra grid is going to do a better job holding up than the poly grid on the Xpac. As far as waterproofness, Xpac has a full laminated layer of PE in the composite construction, while the spectra pack has a PU coating. If waterproofness is the main concern, consider the Xpac, it is likely to stay water-resistant for longer. They will both likely absorb the same amount of water into their nylon layer when it is raining, so that is likely a wash if you are concerned.

If it was me, I’d get the Spectra pack, as is quite nearly the same cost, and I believe the better fabric (to me it looks better too) – it will last longer and be in better shape if you end up wanting to sell it – it will likely fetch higher resale value. I never trust the pack to keep my stuff completely dry, using a liner or dry bag for my sleep system at all times. It is 2-3oz of peace of mind.

First things first: Spectra/Dyneema is a fiber…not a fabric.  DCF is the actual fabric produced from the fibers.  Splitting hairs, yes, but in case someone reads this thread and doesn’t already know the terms, we should clarify them.

Next: yes, X-Pac is a laminated fabric consisting of four or five layers…but it does not use the lamination technology that existed years ago.  The waterproof film layer is now more or less permanently bonded to the core fabric and grid and backed on both sides with abrasion-resistant materials: the result is an extremely durable material that was, coincidentally, also originally a sailcloth like DCF.

All of the X-Pac variants use a similar waterproof film layer, if I’m not mistaken, but the face fabrics and some of the cores differ; some have DCF/polyester outers, some have nylon packcloth, and the most robust use Cordura blends.  Durability, abrasion-resistance and weight are all variable, but in general, X-Pac is considered to be more durable than the pure DCF materials.  That linked article isn’t the only source for the contentious statement that I just made, either; I’ve anecdotally heard the exact same thing from several pack makers…and in all fairness, I’ve also heard the exact opposite, so perhaps the jury is still out.  Thus, I won’t directly quote anyone except aforementioned article and the person that built my latest pack: John at Alpine Luddites, who will not use DCF for technical alpine bags.  In questioning him on that policy, his response boiled down to DCF simply not being as robust and durable in this specific application.

As can be inferred, I went with X-Pac on my last bag…so I’m somewhat biased, but the info I offer is some of what I used to make my own decisions.  That being said: if one is not concerned about durability, price differences or any possible weight differences, it only makes sense to go with the less-expensive product…especially if one is sure that either product will be suitable for their usage.

As another note, the type of failure you are likely to see from Xpac with regards to it’s PET layer is failure from creases causing weak spots in the PET layer, or from abrasion of the face fabric wearing through the PET and causing a hole. I’ve seen more reports online of the Xpac reinforcements getting worn down prematurely, since they stick out above the face fabric. The same can be said for the Spectra grid fabric, with the Spectra fibers being 200D vs the face fabric 100D. I think the Spectra grid fibers should be able to take the punishment more so than the polyester reinforcements of the Xpac, and there are also more Spectra fibers in the mix than polyester fibers in the Xpac. I think the PET liner will hold up better long term than the PU coating of the Spectra grid fabric, but waterproofness would be below abrasion resistance in my list of priorities.

The Flight Xpac bag is $20 cheaper, and also has Spectra grid in the main expected wear areas, so it may be the better designed pack in terms of proper material selection. I still prefer the look of the all Spectra grid :).

I knew if I put a question out here I would get good information. Thanks for the responses and I just need to make a choice, as I think either pack will work fine. But now I have a better understanding of how they are different. As always I learn something from the individuals that participate on BPL.

RSBTR has a podcast and the did an interview with someone from Dimension Polyant (who makes xpac) they answer a lot of common questions and get into the technical side of things.

That link should be it on Spotify, you can probably find it elsewhere as well that’s just where I listened to it

@Bonzo – The Spectra fabric being discussed is not DCF, it’s a nylon based fabric with Spectra reinforcement similar to but not the same as the 210d Dyneema Grid fabric that has been used on packs for years.   The Spectra grid Seek Outside uses has a smaller Spectra grid and is lighter overall.  It’s new, and as far as I am aware, isn’t used on any other pack.

Full woven Spectra (or Dyneema) is another story altogether as well as I’m sure you know.

The Spectra fabric being discussed is not DCF, it’s a nylon based fabric with Spectra reinforcement similar to but not the same as the 210d Dyneema Grid fabric that has been used on packs for years.   The Spectra grid Seek Outside uses has a smaller Spectra grid and is lighter overall.  It’s new, and as far as I am aware, isn’t used on any other pack.

Good timing on this, because I was just looking something up to ease a growing sense of confusion…

I was mostly commenting on the X-Pac fabrics, but yes, the “all-Spectra” designator really confused me for a moment because I didn’t know that they were using an all-Spectra fabric: as far as I knew that pack wasn’t available with an actual all-Spectra build.  I thought it was either a hybrid using X-Pac and their proprietary nylon-Spectra weave, or totally made from the nylon-Spectra stuff; actual all-Spectra fabric – à la DCF or the like – wasn’t an option as far as I knew…and it turns out that I was right, thus my confusion.  They still have the same two options, so I was misinterpreting “all-Spectra” to be something that it isn’t; that’s my mistake.  On their site they name the option “Solid SpectraGrid” and yes, that’s basically an updated version of 210 Dyneema Grid.

And yeah, actual all-Spectra/Dyneema is an entirely different beast than a gridded fabric like 210DG.  I’m honestly not a fan of the stuff in most uses; certainly not in packs.

True: “All Spectra” or “Full Dyneema” both of which you see fairly often are poorly worded as you’re right in most cases the person isn’t talking about a full woven Dyneema/Spectra pack as they are quite rare (and expensive).

All these posts about spectra has me reminiscing about KELTY’S ULTRALIGHT BACKPACK THE CLOUD , I remember when they came out in the 90s and everybody being shocked at the price(and how light they were)I saw one in person at a store near where I lived. They are very rare to find for sale and highly sought after now, sorry to interrupt….Now back to your conversation.

I was going to order a 4,800 custom bag from Seek Outside and was trying to decide between the X-21 XPac and the SpectraGrid.  Last week, I just got a Gila in the X-21 and have had it out a few times so I already know what to expect from that–and I really like it.

I know absolutely nothing the SpectraGrid although Kevin has mentioned he really likes it.

Any thoughts about how the X-21 compares to the SpectraGrid? Similar weight? Which would you choose?

I think the Xpac is best for the main pack bag and the SpectraGrid makes a good accessory pocket material. Like how SO did the Xpac/ SpectraGrid Flight One. Xpac is more durably waterproof and is a stiffer fabric; perfect main bag material. SpectraGrid Has a softer hand and is more abrasion resistant; nice for bottle and front stuff pockets. The weight difference would be negligible. Go for function.

@phillip-ak hit the nail on the head.  The X-Pac is more waterproof and stiffer, the Spectra Grid is more abrasion resistant and has a softer hand. Both are nice all around fabrics so you really can’t go wrong with either, but if you hike where it rains a lot the X-Pac might be preferred, or if you go off trail around granite or sandstone the Spectra gird might be the better option.

From purely an aesthetic perspective, I really like the look of SO’s camo pattern bags in X-33. Have you had any experience with it?

X-33 is supposed to be a fantastic fabric -being as abrasion resistant as X-42 but lighter.  I’d use it but I don’t like camo gear!  If you like the camo and don’t mind the slight weight penalty, it would be a great choice.