Cuben Stuffsack – Bonded

[Colin Krusor]

I'm wondering if some of the floating fly-fishing lines might work for drawcords. I think they're just thin braided or monofilament line covered with a very thin layer of EVA foam. The spongy sheath might protect the cuben from being cut, and it could also make the cord more grippable with fingers and cordlocks than bare fishing line.

[Roger Caffin]

Considering the microscopic weight of the drawcord, ordinary nylon mason's line or bricklayer's line will be just as good, and being nylon you can tie knots in it safely.
Well, that's what I use, anyhow. (Fluoro pink, actually!)

Cheers

[Huzefa @ Blue Bolt Gear]

Thanks Steven.

One way to check if you were using 3M 9485pc tape- can you see a adhesive carrier when the liner is removed? If yes then it is not 9485pc.

The reason I was planning to use tape was ease of use. I dont have time to paint. But this thinner nozel looks like a good idea. Spreading shouldnt take as much time. I will try to look for something similar today.

[Matthew Roberts]

The weight in that Cordlock photo he has on his website is incorrect. The cordlocks do not weigh .567 grams. It's more around .333 grams.

I just put 3 of the ZPack mini cordlocks on my scale. They are right under 1 gram for all three cordlocks together. The digital scale is flickering between 0 grams and 1 gram.

I would imagine he is taking a more marketing approach by listing the cord lock at a round number, .02ounces. It reads better than .01174ounces.

[Steven Evans]

I think I'll just look for the lightest line I can find, I'll keep my eyes open for the pink stuff though/

Huzefa, I don't know what an 'adhesive carrier' is, honestly, I just go by the label on the box. What makes you think it is not the 3M tape? I tested 3 different types (all 3M products) of tape.

Matthew, thanks for the clarification on the weights. I can't believe it has come down do splitting grams…

[Huzefa @ Blue Bolt Gear]

I am not doubting that it is 3M tape, I am saying that it may not be 9485PC tape. This is the one recommended by CubicTech.

Carrier can be a tissue or film which is left on the surface after you remove the thick liner.

[Huzefa @ Blue Bolt Gear]

I am thinking how a solid mini roller work instead of brush. Spreading would take much less time.

[Roger Caffin]

> I don't know what an 'adhesive carrier' is,

There are two sorts of 'double-sided adhesive tape' available.

One sort has adhesive on both sides of a film carrier. The film is like what you get on ordinary office sticky tape. It might be 1 mil PET or Mylar for instance. If bonding very light fabrics the plastic film may control the stiffness of the resulting bond. This can be a problem sometimes.

The other sort is called a 'transfer tape'. It is cute. You get two layers of release paper (or film) with a single layer of adhesive in between. You take off one layer and bond the tape down (eg onto a layer of Cuben fabric). Then you take off the other layer and are left with a single layer of adhesive on your substrate. Then you stick your other layer of fabric down onto the adhesive. 3M9485 is a very well-known transfer tape widely used by sail-makers for UL spinnakers. The adhesive is strong enough that you don't need to add sewing. In this case the stiffness of the bond is due to your layers of fabric.

One can get transfer tape for silicone surfaces. It bonds silnylon fabric really well, but is extremely expensive and is only available in large orders (so far).

Cheers

[Steven Evans]

I am saying that it may not be 9485PC tape

Huzefa, I have no problem if you doubt that this is 3M 9485PC. However, you should state your theory. I'm not an expert on all these adhesives -> You are saying that my supplier has given me an incorrect and mislabeled product, in which case I will contact them.

I am thinking how a solid mini roller work instead of brush. Spreading would take much less time.

Fine idea. If you can find little disposable ones that would probably work pretty good. I grabbed a bunch of brushes from the dollar store as you have to throw them away every 30 minutes or so as the adhesive dries on it. Of course, if you found a little solid roller like you stated, I think you can clean the remaining off using Ketone.

There are two sorts of 'double-sided adhesive tape' available.

Ahh, I see. Thanks for the explanation. Obviously, my 3M9485 is the transfer style. :)

[Bill Fornshell]

Hi,

I have bought the tape and tried it. I had a "not enough hands" problem with the two side tape and it was heavy. Sewing the Cuben has always worked OK for me.

This Hysol stuff must be a lot lighter. I called my local RS Hughes and they can get it for me in a few days. I ordered a ??-50 ml pack at $13.35. I will try it on a few test items but if it works for me as well as it seems to work for Steve I will try it on a new tarp I am getting ready to cut Cuben for.

[Steven Evans]

Bill,
Let us know how it works out for you. In my experience, the tape is difficult to use, especially if you have long seams. Your sewing will no doubt be a heck of alot quicker. My mom sewed my bivy in probably 10 minutes whereas bonding it would take you MUCH longer.

Last photo…
1/2" overlap seam using Hysol.
Tried to "peel" it apart – cuben material delaminates.

[Huzefa @ Blue Bolt Gear]

Steven, I was just saying that if your tape has an adhesive carrier then it is not 9485pc.

>Obviously, my 3M9485 is the transfer style. :)
It seems that your tape doesnt have adhesive carrier. So it could very well be 9485pc. Not sure why it didnt work for you.

[Steven Evans]

In case anyone was curious. I replaced the cord with some I had lying around from the BPL nano guyline kit. Maybe it is Aircore 1? I'm not sure. Anyway, using just a slip knot to cinch the sack, final weight is 2g/0.05 oz…my scale doesn't get anymore accurate then that but I guess it could be slightly more or less…within 0.5 gram.

[Frank Deland]

Here is a cord I really like mainly for tarp or hammock tie-outs: Spectra 1/16" 1.8 oz per 100 ft. It works well for stuff sacks. "No Tangle Guy Lines"

http://www.speerhammocks.com/Products/Supplies.htm

Small cord locks are available at thru-hiker.com

http://thru-hiker.com/materials/hardware.php

NB the "Monoject 412" dispenser at that site, sold as a dispenser for seam sealant.

[Scott Bentz]

Stephen,

I am planning on buying some cuben for my son. He wanted to sew a backpack for this summer. However, after reading this thread I may just get the material and either use tape or solvent.

Do you agree that a solvent seamed cuben pack would be strong enough?

Scott

[Steven Evans]

Scott,
I'd like to say that bonding it would be stronger, but I haven't played around with sewing the cuben to be able to give you a real answer.
If I were going to do a side by side comparison, I would really have to try sewing the cuben using various stitch techniques and seams. It also depends on which weight of cuben you will be using. My cuben gear from MLD is bomber in my opinion, and it is sewn in some areas and bonded in others. I think the design of the joint/seam is a bit more important, especially on the lighter cuben products.
That said, if I was using the 0.33oz stuff, I would not hesitate to bond a backpack/tarp together…keep in mind that I think it will be more difficult/time consuming to bond then to sew.
Bill will probably have a better idea after he tries out the adhesive because he's been sewing cuben ever since he invented it. ;)

[Colin Krusor]

Steve,

I noticed that Loctite makes a low-viscosity version of the Hysol U-09fl called U-09lv. I don't know that lower viscosity would actually be an advantage in any MYOG application, but I was wondering if you had any opinions on it.

[Steven Evans]

Colin,
Nice find. I'll have to take a look at that as I wasn't aware of it. It would be nice to have a lower viscosity adhesive…reason being that the U-09fl is kinda thick so it goes on thick and doesn't spread very far, and perhaps the lower viscosity will give a longer working time.

Thanks for the heads up.

[Derek Goffin]

There seems to be 2 ways people are trying bonding cuben:
Steve's way of glueing with hysol with half inch glue line or
sewing with long stitches and using aquaseal as recommended by Cubic tech.
My tarp tent project has curved seams and it seems to me difficult to glue without sewing with a curved seam and then press while it sets. Hysol is expensive and sets quite fast.
On the other hand Aquaseal has inferior peel properties.
Aquaseal is thick and gooey compared to hysol and I believe that all glue joints will be stronger if they are very thin and set under pressure.
Aquaseal has a solvent, thinner, accelerator called Cotol 240. Ray Jardin believes that it might improve the strength of the glue. This may be because it is easier to get a thin glue line with a runnier glue, or maybe it is really stronger.
Anyway I now have a test jig for testing samples under tension. A clamp hanging from a rope in my basement with 1" square ply spreaders and another similar clamp holding up a bucket. With small 2" x 1" cuben pieces glued in pairs with a 1" square overlap between the clamps I hope to fill the bucket with sand until the sample breaks then weigh the lower clamp and sand bucket. I at the moment have 3 trials glued up and waiting to cure to full strength. 1) hysol,2) Aquaseal, 3) Aquaseal 3 parts to 1 part cotol. I also have sewn a 2 1/4" x 1" (sewn 1/4" from one end) to a 2" x 1" (sewn 1" from either end) cuben. This will open up to glue a 1" square overlap with the best performing of the aquaseal or Aquaseal + cotol.With double stitched seams people recommend tensioning the first stitching while sewing the next. With this set up we are relying on the glue. I do not believe tension will be helpful. When set I will stitch the other side to reinforce against peel and test this 4th sample.
This last test is the likely way I will do the 4 main seams of my cuben tarp. Hysol is expensive. Aquaseal hopefully can be improved against peel by sewing. Sewing one side before glueing will hopefully make glueing curved seams easier to control and press. although Steve has found 1/2" more than adequate with hysol. I think I will use 1" width glue seams if I use Aquaseal. My cuben is the .75 not the .33.
I should run the first 3 tests this weekend.

[adam peterson]

Nice looking stuff sack, i ordered and made the stuff sacks from quest outfitters they sell a 1/2 inch tape for use with Cuben. the stuffs sacks seem to be holding up well but i would agree that tape is kind of a pain to work with. they also sell the mini mini cord locks.

After watching Steve’s video (www.suluk46.com) on the construction of a tarp im going to try the Hysol and make some of the flat stuff sacks to organize a few of the small items in my sundries stuff sack. id love to hear more of anyone’s experience out the field with a glued ridge seem.

oh Frank, thanks for the information on the 1/6 line, with the sheath you should be able to knot without any problems.

[Derek Goffin]

I realized I was doing this the wrong way round making a complicated cuben tarp before a stuff sack. I want to make a large (rucksack liner) stuff sack with a fully water proof canoe closure though. Has anyone made one of those?
I think I have everything I need except a piece of very thin stiff plastic sheet to put in a sleeve to roll the canoe closure around.

[Derek Goffin]

I completed my tensile tests of cuben to cuben glued with hysol U09fl, Aquaseal and Aquaseal 4 parts cotol 240 1 part. All glued at room temperature for 44 hours.
They will have to be repeated because the glue was stronger than the cuben.
I tested the hysol first. I tried hard to get the clamps of my set up all even so that the 25mm glued square was evenly stressed . I loaded slowly with sand in the bucket over about 10 minutes and failure happened at 27.5 kilo. Failure was along the bottom edge of the top wooden square clamp washers. I had rounded the edge of these. The glued area was intact.
I tried the Aquaseal and on reaching 29.5 kilo I stopped, without failure. Similarly the Aquaseal plus Cotol took 29.5 kilo without failure.
Looking up the 25 gram per metre breen cuben on the cubic tech website it should take 105 pounds per inch. It in fact took 60.5 pounds over an inch width of test 58% of optimum. I am pretty sure the spectra threads broke one after another from the sound they made. So I must have loaded the sample more heavily on one edge.
The hysol data sheet I saw gave lapshear strength of from one to 12.5 Newtons per sq.mm (1.5 nylon, 10 polycarbonate). The hysol glue on the sample survived 27.5 kilogram force= 270 Newtons over 25 x 25 mm . That is 0.43 Newtons per sq.mm. I will repeat the trial with a glue overlap of only 1/4" x 3/4" wide, in a few days time. 27.5 kilo will put 2.5 Newton per sq.mm force on the glue. Hopefully that will find the strongest glue.
I tried a peel test just by pulling with my fingers. I thought the hysol was best and the aquaseal plus Cotol was worst . In every case the glue failed not the fabric. Even the hysol was not difficult when you had it started. I must say stitching may be worth it with all those glues. I will test glued samples to see how much weaker the fabric is after stitching.
The only conclusion so far is that a 1" wide glued seam is more than is needed even with CT2K.08 cuben. Lighter cuben fabrics would need even less width

[Nia Schmald]

Thanks Derek. This is good info. When you're done I'd love to see this written up in an article so it is possible to find.

Edit: I just remembered we have the BPL wiki. How much effort would it be to throw up there?

[Steven Evans]

Derek, this is great info. Thanks for doing that. When I bond (hysol) the 0.33 cuben, the material fails and not the glue even when I try to peel it (take a look at the pic I posted on the other page). I'm guessing that since you are using a stronger cuben, the bond will peel easier and not damage the fabric?…any thoughts?

[Derek Goffin]

I will investigate the Wici. Steve When I looked harder there was an area with the hysol where the membrane had delaminated rather than the glue alone failing in peel. The 0.33 has many less reinforcing threads so I can imagine with a peel strength which does not vary with cuben type the glue on the weaker cuben is pulling a bigger area of plastic membrane through the squares of mesh to get the failure in your sample. In mine for the first half inch the glue failed then the glued membrane and one ply of the threads ( all those in one direction) ripped up leaving the back membrane and the other ply of threads. about 1/4 of the area.
As far as shear in seams goes, hysol with 0.33 should not need a lot of glue, maybe sewing 0.33 will not help peel either and will definitely weaken the fabric. With 0.33 the forces just have to be dissipated widely enough. I am undecided about hysol and my 25 gram stuff (what is called 0.6 I think) Checking the Aquaseal and Aquaseal plus cotol neither material was damaged so sewing should help peel with them.
I am quite taken with the small sample of curved seam I sewed ready to glue so from an assembly point of view sewing at least one edge might be good anyway. Complicated curved glued assembly will probably lead to a greater risk of inadvertent tight spots which will be the beginning of failures at those stress points.
This cuben is strong stuff, only an inch width holding a full large bucket of sand was impressive. 65 gram silnylon (I think that is 45 denier) would not have held that even if perfectly loaded.
The 3 new samples are gluing under some books so some time after Tuesday I will try again

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