Help me decide: cuben vs. silnylon for Skyscape upgrade

"I mean no disrespect to you, Tom."

I know that, Steven, and no offense was taken to your comments. They were directed elsewhere and intended to be a one off response. I have no interest in getting down in the weeds on this one and am prepared to let it go here and now. It wasn't that big a deal in the first place.

"I guess if I was getting a Skyscape as my ONLY shelter, then I would be really interested in the Cuben X. If I was getting one for a main shelter but still had a lighter tarp I could use when I wanted, then the Sil version is worth a look. Does that make sense?"

Yes, it makes sense. My situation is that the Skyscape X is intended to be my only shelter for 3 season Sierra trips, where I do most of my backpacking. I do have a TT Rainbow, but seldom use it anymore due to weight considerations, and have been using a tarp/bivy combo for the past few years for that reason. I keep it around as a loaner, and intend to make the Skyscape X my only shelter. If the floor doesn't hold up, I will have it replaced with heavier Cuben at season's end. I am hoping that a polycryo ground cloth and careful site selection will make that unnecessary. In any case, it was a carefully thought out, calculated risk. We shall see…

" I just don't think 0.74oz offers sufficient long term durability for use as a floor (based on quite a bit of use of the stuff over the past 3 years in a variety of applications). It's a big compromise to save 2oz (based on 3 yards of floor material). IMO 0.74oz cuben floors are really only suited to niche applications in the XUL world."

Now we're having the conversation I want to have. You raise very good points here, and I may well end up with the heavier floor at the end of the season, especially if the polycryo ends up being a wash, weightwise. This is my first foray into the Cuben world and the Skyscape X will definitely be a learning experience for me, hopefully not too much more expensive than it already is. Thanks for the experience based info, Dan.

My guess is that the polycryo will protect the .74 cuben well enough that it holds up for you and won't need replacing.

Without the polycryo, I'd speculate you'd have a few small holes within 10 nights – perhaps not visible ones but pinholes at least that would let water through under any pressure. I'm hesitant to speculate too much, but I'd be very surprised if someone could thru hike with a .74 cuben floor (and no groundsheet) and not wind up with significant delamination and large holes.

I hope I don't come across as a cuben hater – I love the stuff and have tons of it from 0.33oz to 2.92oz cuben/nylon hybrid. It's amazingly strong and thus super for tarps and tent shells. I've got my eye on gear swap now for a cuben Solo/DuoMid. It just doesn't do very well under abrasion as the material starts to delaminate and then it goes downhill quickly from there.

Dan – If the tent is not available in Cuben without the thinner film (.08) on the floor, then I agree that the polycro is needed; but as was pointed out, there are still significant weight savings from the Cuben for the whole tent. Also, even the most water resistant silnylons, like the one T-H currently sells, are not exactly bomber proof for a floor, and many might prefer a ground sheet for those also. The absence of sagging in the canopy is a plus also.

You have a lot of experience with the Cuben materials, in both ready made and MYOG applications, and I appreciate your sharing it. Glad to hear that you are OK with the thicker film (.18) Cuben materials for floors, as am leaning toward that over the silnylon. Some of the silnylons, like the Cordura that Judy has used, are more robust for the same weight, but unfortunately, less water resistant. I wish the stuff that Henry uses for floors were available for MYOG. T-H had something like it, but it sold out and it was not restocked. I used it for the floor of a tent, and have had no leakage or wet-thru in many heavy rains. Wish I'd bought a bunch.

Wonder if the OP has reached a decision yet.

I'm getting a bit off topic here, but my ideal fabric for a floor would be a PU coated 30D nylon – which is basically what most lightweight mainstream tents use. It's just a smidge heavier than silnylon at about 1.5oz vs. 1.3oz.

With a PU coating instead of sil, you can get far higher waterproof ratings (up to 10,000mm) and the floor isn't slippery. Silnylon has a higher tear strength, but with due care I've never had an issue with a 30D nylon floor tearing, be it silnylon or PU nylon.

If price was no object, I'd choose 1.2oz cuben next, then silnylon…..mostly because of the slipperyness of silnylon but also because of the waterproofness of 1.2oz cuben. I'm not sure which would last longer but they both should be reasonable.

Not my forte. But this thread has given me ample food for thought. Being in SF, most of my backpacking gets done in the sierras. So I'm often pitched on some pretty rough rocks. Though I often use polycro in those situations, I hate to be dependent on it. the whole .74/1.0+ cuben debate has me thinking I'll grab the silnylon and wait for others to report back on their experience. Still like the idea, but I do camp on some very rough ground.

"My guess is that the polycryo will protect the .74 cuben well enough that it holds up for you and won't need replacing."

That is what I was hoping for, as polycryo is a lot cheaper than retrofitting a heavier Cuben floor to the tent, but it's good to hear it from someone who has real world experience with Cuben. Thanks, Dan. And to all the others with Cuben experience. I am getting a pretty good education here.

Hey Everybody,

Sorry for not seeing this sooner and responding. I have been down and out for awhile due to an ITB issue with one of my knees.

And this might be a rather long post…

@Charles Pearson — But: though he reports being satisfied with durability of 0.74 cuben fiber for the canopy, he would like to see an option to have a bathtub/floor made of 1.24 cuben fiber.

As I indicated in my article I have used a cut-down Gossamer Gear 1/8th sleeping pad and throw it underneath the shelter and problem solved. I also indicated that I have used the Gossamer Gear Polycryo ground cloth underneath the shelter – and ask just about any thru-hiker and they can tell you that they are amazingly tough. The nice thing about these is it also gives you a secondary vapor barrier, which the 1/8th pad does not.

This would also be a good point to remind those of you with one, or planning to buy one, that SMD has not bonded/sealed their floors. Why, I have no idea. It baffles me why they went to such extensive lengths to tape bound the rest of the shelter, and than they do not also tape-bond the floor. I/we can only hope that they do so with their next batch of this shelter. If they do not, first thing I will be doing when mine shows up (yes, I am buying another one) will be to put some single sided Cuben Fiber tape from ZPacks on every corner and seam of the floor. I will also be attaching some additional layers of cuben fiber where the poles come into contact with the floor on the inside. Ron has told me that they already have an additional layer of CF in that spot, but it still does not feel like it is enough. I will just take some spare 0.74 cf I have and cut out some round disks and tape-bond them onto the floor. Probably totally unnecessary, but I really hate being inside of a shelter when the weather is bad wondering if my shelter is going to fail. A few minutes of my time to make this reenforcement just seems logical to me. Highly doubt it needs to be done, but I spend too much of my life out on the trail to have to worry about something that can be solved easily.

But anyway, yes, the SMDSX floor (previous production runs) have all been made of 0.74 CF floors.

For those who have not seen it, here is a very sweet video of the CNC machine that SMD is using to cut their shelters.

@Tom Kirchner — Myself, as well, and I’ve bet $450 that Ron will be amenable to that, especially if user feedback indicates problems with the .74 Cuben. He has integrity and cares about customer satisfaction, not to mention making sure his products are manufactured to the highest standards. It’ll be interesting to see how this one plays out as folks gain experience with the current version of “X”. As I said, I put $450 on the line, despite questions about the floor, based on the above assumption. I’m not worried.

In my review of the SMDSX I did say that I would love to see a true bathtub made of heavier weight material. Do I think this will ever happen? No. The SMDSX is a sub-one-pound fully enclosed shelter – and that is a huge accomplishment! There is no way that it could remain a sub-one-pound shelter with any heavier weight material and I suspect that in the end Ron would care more about having the SMDSX remain a sub-one-pound shelter in his catalog of products.

There are very few sub 20 ounce fully enclosed shelters on the market. The SMD SX is 465 grams / 16.40 oz / 1.025 pounds. Based on my research, this is the worlds lightest Total Shelter Weight one-piece fully enclosed shelter! Add two 0.292 carbon fiber poles for a Total Shelter Weight of 502.79 grams, 17.73 ounces, 1.108 pounds. Nobody else in the world (as of time of this writing, AFAIK) can claim this low of a weight for a fully enclosed one-piece shelter. Not Terra Nova (though they falsely claim this, their TSW is laughably heavier) and neither can ZPacks as they do not have a one-piece fully enclosed shelter (you still have to have a bathtub floor when it rains, which thereby turns the Hexamid into a two-piece shelter) so what Ron has done with the Six Moon Designs, Skyscape X I am not sure anybody else out there (minus perhaps a DIYer) can claim that they manufacture and sell. So, yeah, I highly doubt that unless the shelter starts having serious flaws in its floor, there is very little likely hood of them switching up to a strong weight material.

@Dan Durston — If price was no object, I’d choose 1.2oz cuben next, then silnylon…..mostly because of the slipperyness of silnylon but also because of the waterproofness of 1.2oz cuben. I’m not sure which would last longer but they both should be reasonable. … IMO 0.74oz cuben floors are really only suited to niche applications in the XUL world.

Hey Dan, This is something that has been an interesting discussion with myself and a few other SUL/XUL hikers as of late. I have been trying to make the point the last few months that CF as a floor material makes no logical sense. By the time you use a CF material strong enough to be able to throw it down anywhere, you might as well just go with Silnylon. I kind of really hate to say this, because I have been pushing the whole CF thing for a few years now – I do believe in CF – but if you are a hiker who does not desire to carry a secondary item (ground protection of some kind) than CF sort of does not make any sense. Case in point, look at the very awesome HMG Echo I Insert. It has truly the best bathtub/insert of any insert that exists IMHO. But it comes at a price, a freaking 11.5 ounces price!! I have called the HMG Echo Shelters the “world most bombproof CF shelter” – and I have yet to find a CF shelter that can take the abuse a HMG shelter can take – but that equates to them using heavy CF and thus you have a 29.5 ounce CUBEN FIBER shelter. Ouch! (as you yourself know). At some point the logic that CF used as a bathtub floor (without secondary ground protection) is something I have began to ponder on.

When I go out with my sub 2 pound BPW setup I would use a 1.0 CF ground cloth (see photo) and even the 1.0 CF was not something I would put directly onto anything but soft ground. Roots, rocks, granite tops, etc, would just chew up 1.0 CF without even thinking about it.

I totally understand what you are getting at, but I am not really aware of any XUL application where I would want to put 0.74 CF directly onto the ground for any long distance hike. I am sure others out there are willing to do so, but here in the Redwood rain forest of Northern California, water on the ground is probably of bigger threat to me than anything else, so a bathtub floor is of paramount importance.

@Tom Kirchner — intend to make the Skyscape X my only shelter. If the floor doesn’t hold up, I will have it replaced with heavier Cuben at season’s end. I am hoping that a polycryo ground cloth and careful site selection will make that unnecessary. In any case, it was a carefully thought out, calculated risk. We shall see… This is my first foray into the Cuben world and the Skyscape X will definitely be a learning experience for me

That is very awesome!! I think if I were to pick one CF shelter on the market today as my one-and-only shelter it would have to be the Six Moon Designs, Skyscape X. It can give you bug protection in those times of the year when you need it. It can open up on both sides to let an insane amount of air through in the hot seasons. It has a very awesome 75/25 apex which gives it a feel of a lot of headroom inside. And SMD has probably the best engineered gear of anybody that makes UL shelters here in the USA.

Please keep me updated on how it works out for you!

Anyway guys, sorry this post was so long and I went rambling on about stuff. If you have not seen it be sure to read my SUL/XUL Fully Enclosed One-Piece Shelter Comparisons article and spreadsheet that I wrote up a few months back. And my full thoughts on the SMX SX is located here. I suppose I should also disclose that I do not recommend using 0.292 carbon fiber poles with this shelter, as I mentioned in my article. They are just not able to handle really strong wind gusts from the side. Bounce up to the slightly heavier 0.355 carbon fiber poles if you expect to be hiking in areas where it is really windy. The 0.292 fibraplex poles can handle around 30 mph winds, but much beyond that (if you get hit on the side of the shelter) and the poles start bending to a point of major concern.

-Abela
HikeLighter.Com

(updated: fixed a typo – sigh, probably a lot more in there)

John, I really appreciate you re-visiting this topic for my benefit – and I'm sure the benefit of many others in this conversation. Now I have some thinking to do. I already use Polycro (though I'll say readjusting my Scout from inside last weekend in the Sierras [Five Lakes Basin] while pitched on a rock ledge a few feet above the lake I DID tear a small hole in my groundsheet. Luckily GG sends two in the order and, properly trimmed, this one is still serviceable) and you've got me thinking, it's time to play careful, add the soft cushion of a 3/16" CC pad, and enjoy the lighter load. Silnylon likes to be babied as well, and, well, if I go with that, I'll always be thinking about grass somewhat greener. Thanks again.

Great post John. I totally agree with where you're at.

Nice to hear your thoughts on the 1.0oz stuff. I've only used the 1.2 and 1.5 stuff in the .18 mylar range. It sounds like it's noticeably less durable. I guess '1K' worth of spectra is a lot less than the 2.5-5K you find in the 1.2-1.5oz materials.

Regarding the insert of the HMG Echo 1 – you're right that is quite heavy for a cuben shelter component. It feels a bit odd to stuff a 11.5oz inner under a 7oz tarp. Using lighter shockcord and tensioners I was able to drop my Echo I inner to about 10.5, but that's still a lot when you've got lots of silnylon inners out there at 6-9oz.

The 1.0 that I use is the stuff from ZP. I have thought about buying a square yard of their 2.92 oz/sqyd Cuben Hybrid to see how tough it would be for use on the ground in high alpine areas where there is a lot of granite that ends up being where you pitch a shelter at, but man is that stuff expensive.

So here is a question for those of you who use silnylon floors… do you end up using a secondary ground protection item for when you are in wet ground areas and/or areas with a lot of rocks, roots, cactus, etc?? I suppose if the vast majority of people using a secondary ground cover in addition to their silnylon floors, than, I suppose, it could be more logical to go with CF over the silnylon for the additional water barrier protection that CF can provide over SN. Interested in how those of you who use SN floors approach this issue.

"Please keep me updated on how it works out for you!"

You bet, John. I'll be reporting when I'm done for the year.

Great thread, I've learned a lot. If only forums could always be this smart and informative!

All gear has its place.

Some is suited for 1 week UL trip , and may need maintenace afterwards.

Some is better suited for 1 yr, 4000 mile trip, you dont want failures on the trail

I would not dismiss any lightweight gear as being "stupid light". As long as you select gear to meet the needs of a specific trip, there is nothing wrong with it.

On a short trip with good weather, you might take only a bivy for sleeping. On a longer trip that would be "stupid".

FWIW, Skurka has a new blog post up about 'Stupid Light':

http://andrewskurka.com/2012/stupid-light-not-always-right-or-better/

We're getting in a batch of Skyscape X's tomorrow. So I'll be resetting the webpage so they can be ordered. We like to wait until we've got them in hand just to make sure all is well.

We won't be able to ship tomorrow. We've still have to finish the final production phase. This includes taping the seams, applying the re-enforcement patches and sewing on all of the tie outs. This will take us several days to complete. So hopefully we'll be shipping out tents by the end of the week.

I also wanted to make a couple of comments about some of what I've read in this thread. Pardon me if I don't cover all of the topics, I've only been loosely following it so I've not read all of the post.

Changes:

For those who are wondering, there are no changes in this release of the X. Our goal was to begin increasing the volume of tents we make in a single run and iron out some production issues. This will be the first of the Skyscapes cut with the CNC machine. It provides for very accurate cuts at a fraction of the time.

We're going to wait until probably sometime this winter before deciding if we'll make any changes in the tent.

Floor Style:

I know many have questioned the use of cuben fiber as the floor material. Especially the lighter version we're using. I appreciate the concerns, but have no plans for changing at the time being. Sometime ago I wrote an article about my thoughts on Bathtub floors (http://www.sixmoondesigns.com/blog/72-bathtub-floors.html ). I can't say that my feelings have changed on the subject matter overtime.

I will say that I think that the cuben floor is quite superior to using no-see-um netting as a floor material. But then maybe that's just my personal prejudices. Still lots of people buy that kind of shelter thinking nothing about it. Go figure!

Seams & Waterproofing:

John noted that we don't tape the floors (that would be the corners of the floor where the floor material is folded to form the bathtub). The entire floor is a single piece of material so the only seams are at the corner. It's true we don't tape those seams. In fact the only seams we tape are the ones that are structural in nature.

We don't tape the tent to make it waterproof. Any degree of water resistance in the seams is a byproduct of the making the seams strong and not a designed feature. After using Cuben on numerous projects and products over the last 5 years, the weakest characteristic of the material is the joining of multiple pieces together. A fact that most on this list are well aware of. Either by their own CF projects or using products made by others.

To that extent, we decided not to release another CF product until we were sure that our seam technology created seams that were stronger than the underlying fabric. This is something that isn't even true with silicon nylon products.

While I've noted that we tape our seams. I should clarify that our taping is nothing like you've read about from other CF DIY'ers or CF producers. We don't use transfer tape, it's simply not strong or reliable enough for serious use. We make our own glue and have specialized machinery to apply it. It's fairly complex and laborious process and we're working to simplify it.

A number of people have noted that our CF prices are high, which is true. Though they are no higher than most comparable products. I should also note that a significant portion of labor used in the construction of our tents is not currently factored into their cost. We're still in the learning phase and we're working to lower the production cost as we ramp up the production.

Future CF Products:

We do have drawings and plans in place for future CF products. Which one will be the first the appear only time will tell. Right now we're concentrating on the X and Cuben Haven. After that, who knows!

Ron

I appreciate your input and am stoked that the CF Skyscapes could ship as early as next week. Watched the video on your high tech cutting process, very impressive. When I get the call, I will happily forward funds. I think I can respect that I need to keep aware of my site conditions and prepare my site accordingly. The reward? As John has noted, the lightest one piece, one man fully enclosed shelter on the planet.