Cuben Fiber – Q&A

Evan, The standard Cuben Fiber is not “Breathable”.

However, since the backpacking interest in the really light weight of the Cuben Fiber, the company has made one or more test runs of a “Breathable” material. That material to my knowledge is not yet being offered for sale. I was told the test material was in the 0.7 ounce a sq yard weight range.

thanks againn, Ben and Bill, for the reply… [re: breathability]…

Please keep us posted on this breathable Cuben!

Hello Bill,

I was wondering if you knew about current cuben part numbers and corresponding 36″x36″ piece weight?

I’m interested in making a bivy bottom and have read some posts in this thread regarding ~.4oz and ~.6oz cuben, but don’t know which part numbers those would be on the cuben site. I looked on the Data page of their site (http://www.cubenfiber.com/cfdata.html) and found weights in sailmaker’s yardage (27″x36″).

Thanks!

PS. If you or anyone else has any extra cuben I would be interested in buying it instead of buying from the company directly.

Jhaura,

I would think it would be fairly easy to convert the weights from sailmaker’s yards to standard yards.

Ben

Jhaura Wachsman

The Cuben in the .35 oz to .44 oz a sq yard (36″ by 36″) range is CTO.3K.08 and comes 48″ wide. This is the product that I use most of the time and is the two fiber/cord?? kind. What I mean by that is that it has fiber/cords running north and south (1 fiber) and one fiber/cords running east and west (2nd fiber).

The cost, plus S&H, comes to about $17 a yard. They sell only in 9 or so yard pieces unless they have what they call “shorts” . If they have no “shorts” you may have to wait awhile.

I have never used their standard (2 fiber) .6 oz weight product. The closest to a .6 oz product I have is some of the 4 fiber product. The extra 2 fibers/cords run at different angles to the n-s/e-w fiber/cords and give the fiber much greater strength. This comes at a dear price however.

You can buy small amounts of the CTO.3K.08 from Quest Outfitters but I believe it is sold for about $25 a yard. It is or was listed on their web site.

I’ve noticed that people are selling Cuben Fiber tarps, stuff sacks, packs and plenty of do it yourself stuff. However, I’m surprised that no one (to my knowledge) has started using Cuben Fiber for single or double wall tents. Is this just a matter of time, or is there some other reason for this? I would think you could save a lot of weight just by replacing the rain fly/roof (you could leave the floor as silnylon as it is much more likely to tear). I know this stuff is expensive, but I think people would pay for the weight savings (just as they pay for down instead of synthetic).

I have small strips and bits of cuben fiber ck2.
Contact me off list and i can tell you more. Make
me an offer.

do@owareusa.com

Posting this now in case some of you new to working with Cuben Fiber never saw it before. You can read over some of the questions and answers asked in the past.

I know nothing about this topic at all; yet thought there may be some interest in this article on a guy from the UK who is prototyping tarps in this fabric:

http://www.outdoorsmagic.com/news/article/mps/UAN/4468/v/1/sp/

I’m a newbie to cuben fiber, but thought I’d share something I just learned to save others from potential misfortune. Working on a cuben fiber shelter, stuck things together with tape (the Quest outfitters tape, and one other kind). Took it outside, where it’s 10 degrees here in Anchorage this morning. All the tape unstuck – instantly.

So what seems bombproof when you tug on it in the house, may completely fall apart on you on a cold night.

-Erin
Wild Coast Journey

I once tried a little tape on the neck opening of my Poncho / Tarp. That was the last time I tried tape. I just didn't like it and was all thumbs when using it. For me I think thread is lighter and a lot less trouble. I have made a lot of stuff out of Cuben Fiber and have sewn it all. I have had NO trouble with any of my seams not holding.

I have also heard that tape doesn't hold up well to heat.

Before I would bad mouth any tape I would want to know what brand name and what product number was being used that failed and who said it would work.

To blame all tape without more detailed knowledge and testing is silly unless you have a hidden agenda.

ummm… sorry? I wasn't intending to attack or blame or bad mouth anything. No hidden agenda, I promise.

Just noting that some tape (including the one that Quest Outfitters sells with its Cuben Fiber) is cold sensitive. People can take that info for what it's worth.

The note about heat has been made earlier. I just added the one about cold. So, if you're using tape, probably good to think about both ends of the likely temp range the gear will encounter, and test your tape at those extremes.

Erin,

You were correct to post this problem.

I am sure Quest would like to know if their tape has limits to its use.

First I would like to say thanks to Bill for starting this Cuben Fiber Q & A thread last year. I am a "newbiw to cuben fiber and this thread has helped accelerate my learning curve on this material.

To revitalize some discussion in this thread, I am posting pics of my first creations using this interesting material – 4 cuben fiber stuff sacs.

From L to R: Sack for my essentials, Sleeping bag, O2Rainwear shell, Patagonia vest.

I used specta cord and Thru-hikers tiny locks to sinch the sacks.

I am handing down all my silnylon stuff sacs to my kids.

Let the field testing begin. :)

This is my first post. I admire the ingenuity of everyone who posts here, and it helped me to feel a little more intrepid in tackling my first cuben project. I plan to make both a two-pole shelter (similar to the Spinnshelter) and a down "elephant foot" half-bag (similar to the Nunatak Akula) mostly of cuben fiber.

I took a sample of the CN1K.08 to a company here in Oregon and they aluminized one side of it (like a space blanket) for me. The aluminum layer is about 0.3 microns in thickness, or about six times thicker than the layer used for camping/emergency blankets (usually about 0.05 microns). I told them I wanted it to be as robust and resistant to abrasion as possible. It's about 1/19 of the thickness of the cuben laminate itself. I scratched it hard with my fingernail for twenty seconds or so and none of it appeared to come off.

The metal layer adds very little weight (about two hundredths of an ounce per yard), but should improve the warmth of the sleeping bag. For the shelter it may aid in bringing up the air temperature a little when there is a warm, radiant person inside, and it should also help to illuminate the inside with a little LED flashlight. It also blocks all outside light, which might be a benefit for summer camping in Alaska. I hope to make the shelter reversible as well, so the metallized side can be turned out if I should want that.

Also, before I had the cuben sample aluminized, I dyed it with a mixture of disperse dyes (for polyester plastics and fabrics). Although the dye mix was dark brown, the cuben came out tan or beige, which I prefer to the milky, membranous appearance of the undyed cuben. I guess I like the idea of the shelter being approximately dirt-colored on the outside. The dye shouldn't affect the strength of the laminate, and it should increase the weight of the cuben by almost nothing (maybe a few micrograms or milligrams per yard).

Anyway, below are some photos. I have some misgivings about the dye process, and I think I'm going to look for a different aluminization company, so I have some research to do before I modify a large batch of cuben.

Oops. Those photos are huge. Sorry everyone. It's still mostly visible I guess.

Hi Colin,
Interesting idea laminating Aluminum stuff to the Cuben Fiber. I think your sample is small but did you get an idea of how it folds up with the Aluminum stuff on it?

I have played with Sharpie Permanent Marker ink to color a few pieces of Cuben. It works OK but is a lot of time and trouble.

I made an all Cuben Sleeping Bag using 2 layers of Primaloft One – 1.8 ounce a sq yard insulation. It is very warm and do I need to say – water proof.
here is the link to it:

Cuben / PrimaLoft One – Sleeping Bag

Your cuben/primaloft sleeping bag looks great. Did you put it through some summer field testing? Have you been using the bag with your chambered inflatable sleeping pad? I'm making a sleeping pad and I could use all the advice I can get from the expert gear makers. I'll be posting all that in a new thread tonight.

Are you finding that any condensation seems to occur in the insulation layer of your bag on cooler nights? I wondered if, in my design, the air sequestered in the insulation might reach its dewpoint, wet the down, and compromise the loft. I thought about adding vents for daytime drying.

The aluminized cuben sample seems to fold as well as the unmodified cuben and it feels about the same. The aluminum is thicker than the layer applied to space blankets (heatsheets, etc.) but still very thin. It's just over 5% of the thickness of the cuben itself.

Hi Colin,
I'm really happy it is possible do dye cuben, it's color discouraged me a a bit from using it to make a tarp. Could you comment more on what dye have you used and where to get it?

Jan,

I used a mixture of brown disperse dyes from Pro Chemical and Dye (www.prochemical.com). I think disperse dyeing is the only process that can impart a durable hue to polyester film, but it requires boiling the item to be dyed in a vat of noxious, overpowering, petrochemical evil for several hours.

So, I wasn't sure it was going to work. I didn't want to boil cuben because although the film layers are polyester, the fibers are UHMWPE, which has a much lower shrinking temperature. Also, the "swelling agents" in disperse dyes include bromobenzene, hydrobromic acid, and biphenyl (among other things), which are carcinogenic and overpoweringly noxious (it can't be done indoors). I wasn't sure how they might affect the adhesive layer that keeps the cuben intact.

So, I reduced the recommended concentration of the swelling agent cocktail ("Pro Dye Carrier NSC") by 80% and put a generous bead of silicone sealant along the edge of the cuben sample to protect the laminate bond. I left the cuben in the dyebath for five weeks. I heated the bath (to about 180-190 F) for an hour or so every two or three days, but it was mostly room temperature.

The dye mix I used was dark brown, and the sample came out sort of a khaki color. The sample still smells like the swelling agents. The instructions from Pro Chemical explain that the solvent smell can take months to fade.

I'm hoping to find a better method. There are probably other chemists and more experienced dyers among our forum readers. Does anyone else have any ideas?

Hello everyone.
I have tried a bunch of products to bond Cuben to itself and to Momentum90. However, I must say that I have not tried thread! Of all the stuff that I’ve tried, 3M9485 ¾” tape works the best. I have put the bonded Cuben in the deep freezer and in the hot sun and have not had any indication of the bond failing. The bond strengthens with time, although I don’t think by much and I don’t have any numbers for you. I have used 4” wide 3M9442 for the reinforcing corners of my tarp. 3M9442 does not work as well as 3M9485! It is possible to peel the pieces apart and stick them back together long after you tape them together. It is very hard to separate taped pieces in shear (the Cuben has ripped outside the taped area in my tests)
I took some pictures of how I apply the tape.
This 8×10 Tarp weighs 6.6 oz

The pics did not post how I thought they would.
First pic: Using the 9485 tape. Tape the Cuben to the table. The sticky part of the tape rubs off the table with your thumb
Second pic: Tape the two pieces of Cuben together.
Third Pic: The tape has paper backing. Simply fold over and pull off the backing. Follow with your other hand and press down lightly.
Forth pic: Finished seam and hem.
Fifth pic: Next comes the Momentum90/Cuben bivy.

> Of all the stuff that I’ve tried, 3M9485 ¾” tape works the best.

This is one of the preferred 'seam-stick' tapes used by sail makers to make spinnakers out of … (NON-silicone) spinnaker fabric. It makes a permanent bond after a while. No sewing.

I was testing the tape on some Dimension Polyant orange titanium fabric – the air-tight stuff they made for high altitude research balloons. I tried to separate two bits of fabric after a week. The PU membrane ripped off the fabric (delaminated), instead of the tape failing. I was very impressed!

Btw, the fabric was interesting, but it's not so good for tents or for snow.

I tried to access the pics by Scott Peterson of the tarp in this post, but for some reason I can't open the link.

I'm curious as to how the perimeter tieouts are configured if this tarp is 100% no sew. Any help is appreciated.

This might help with converstions between smyd and sqyd:

From: http://www.challengesailcloth.com

The traditional weight of sailcloth in "sailmakers' ounces" is the weight of fabric 28.5" wide by 36" long.

To convert from Sailmakers Yard to Square Yard: multiply by 1.263. So Cuben lists a style as 0.35 oz/smyd, so if we multiply 0.35 by 1.263 we get, 0.44205 oz/sqyd.

Also, sometimes Cuben is listed in grams per square meter (g/sqm):

(1 ounce) per (square yard) = 33.9057475 gram per (square meter)

So 18 g/sqm of Cuben = 18 / 33.9 = 0.53 oz/sqyd

the inverse:

1 gram per (square meter) = 0.0294935247 ounce per (square yard)

So 18 g/sqm of Cuben = 18 * 0.029 = 0.53 oz/sqyd