Cuben Stuffsack – Bonded

Awesome. Almost makes me want to buy some cuben and make some. Maybe a packliner?

Steve,

PM me your snailmail addr and I'll send you some AirCore 1 line and a tiny cordlock so you can ditch that porky drawcord string (he-he).

(serious offer)

Steven,
Very nice !!! I had always wondered how easy it was to use the Hysol glue. Did you use the Hysol from a gun using a dual mixing applicator ?? What is the set-up time ??

When I use the 3-M tape I usually cut it in half with a sharp razer blade to save weight on all non main bearing seams. Looks like the glue is a better way to go !!!!
Might have to really look at this option for the two man cuben tent.
Thanks
Kevin

Jim, thanks for the offer. I used the same line that came with my MLD Cuben Poncho…because I had some. I won't bother you to send it, but where do you get the tiny cord locks from? I looked for a bit but they all seemed so heavy…the ones on the nano sacks are super tiny. I couldn't find them anywhere.

Looking back at the pictures, the line I used looks like climbing rope. :)

Where do you get the adhesive? I found only one place on the net:

http://www.amazon.com/Loctite-U-09FL-Urethane-Adhesive-Flexible/dp/B000WXL1UI/ref=sr_1_1?ie=UTF8&s=industrial&qid=1239048687&sr=1-1

I searched for Loctite Hysol U-09FL

<–also interested in stupidly tiny cordlocks.

Edit: purchased 20x stupidly tiny cordlocks.

zpacks.com sells tiny cordlocks.

I think these are "tiny" cordlocks, but maybe there is a source for something even smaller? I dont know how much smaller is feasible to still function…

"mini" cordlocks from OWF Inc.
http://owfinc.com/Hardware/phardware.asp#Cordlocks

"mini mini" cordlocks from Quest (measures 5/8" x 3/8" wide. Each weighs .015 oz. each)
http://questoutfitters.com/plastic.htm#Acetal%20Fasteners

I think they are both comparable in size, but could be mistaken.

Great looking bag, almost has me inspired to buy some cuben too!

Hey Kevin,
I have the applicator gun but just squirted a small amount on scrap cardboard, mixed it, and applied it with a paintbrush. The gun really pushes alot out and fast, and I think it would be impossible to do any precision work with it. Maybe if you were bonding huge sheets together or something. If you were just doing something small, I'd pass on the gun and just push the stuff out with your thumbs and make sure each cartridge is relatively equal. Of course, if you are building another one of those shelters…it could get time consuming.
It states working time to be 10 minutes but you can pull apart the pieces for probably 30 minutes which makes it easy to adjust seams and stuff. It starts to become difficult to apply with a paintbrush (becomes gummy) after the 10 minute mark. I mix small batches at a time cuz this stuff gets pretty pricey. I have limited experience, but it probably takes full 24 hours to dry and then another 24 to dry clear (the stuff on my bag is still a bit milky after a day or so).

I actually used the 3M tape on a couple of other test samples and found the peel and shear strength to be less then the Hysol but still acceptable. Also, the tape is so tough to line up and apply all at once, especially on very long sections (ie. like a bivy). This cuben is really thin so sometimes if you breath or move you arm fast it will move the fabric and mess things up. The Hysol allows for re-application and adjustment.

Roleigh,
My apologies…I have edited my post to show the correct adhesive which is Hysol U-09FL. I purchased it from my local supplier Fastenal. They require a $150 minimum on the stuff but we have an account so sometimes they can piggyback it on another order. It is an industrial product but I'm sure you can buy it somewhere down in the States and probably without the minimum order.

Maybe try RS Hughes?

Steve

RS Hughes and Mcmaster Carr carry it.

http://www.mcmaster.com/#6430a32/=1bzvd8

Steven, thanks. I see the amazon link actually has the supplier as R. S. Hughes Co., Inc.., the amazon unit is about twice as heavy as the other, which probably accounts for the price difference.

Awesome.
Great job, and right up my alley.
Opens a whole new field of possibilities for me.

I bought a used school sewing machine 10 years
ago and can't make it work right. Tried to learn
on cotton scrap, but no way. Can't find anyone around to
either teach me, or repair my machine if it needs it.
I have no idea if it is me or the machine.
One local guy said he would teach me whatever I wanted
IF I purchased a new machine from him. I've been considering it.

Thanks for posting this!

Steven,
Thanks for all the info. I'm going to do some research and see if I can come up with a little quicker drying Hysol. Need something more along the lines of 5 minutes.

Using the inexpensive duel component plastic mixer on the front of the gun/tubes works great in getting the perfect and clean mix and then applying small beads of the glue in the exact area that you need it for just a little extra money. Plus, no extra waste. Here is a small picture. You can get these at McMaster-Carr or RS Huges as well. Will definitely use this on the next shelter !!!

I have purchased both size cord locks from ZPacks. The smaller of the two sizes is on just about everything I own with a cord.

Highly recommended.

…

http://www.zpacks.com/accessories/spectra_cord.shtml

Steven, nice work. Interesting info on loctite.

Kevin, are you planning on using loctite on load bearing seams? I am not sure if a single line from the above mixer can give a strong seam.

Kevin,
Thanks for the picture. That is definitely different then the one I have. The one that came with the gun extrudes a wide ribbon of glue. I didn't realize there were different ones. I will look into that ASAP.

Mathew, thanks for the link but believe it or not, 0.02 oz is too heavy to put on this bag :o…that's over 1/2 a gram, which is 25% of the weight of my cuben stuffsack sans cord.

What is the lightest cord out there right now? Is it the BPL aircore 1? Pretty expensive. Z-packs has some light stuff but I thought maybe someone knows of something ridiculous light…

Huzefa, if the joint is designed correctly (forces on bond are in shear) I think Kevin will be good. My test samples using 0.33 cuben with 1/2" seams have proved fine after trying my hardest to pry them apart. Even my all cuben corner stake loops cannot be pulled from the body of my tarp…using only 0.33 cuben and the Hysol adhesive.

Fishing Line is pretty lite. Braided line tends to cut things, but mono seems to do pretty well on my bags.

Steven, as you may know, in a bonded surface load is spread throughout the contact area. 1/2" seam should be good. But the nozel in kevin's pic looks much narrower. Have you found any accessory that can extrude 1/2" ribbon?

Have you made a tarp bonded with Hysol???

btw have you done any calculations of bonding strengths of 3M 9485PC tape and Hysol U09FL to polyester film ie Cuben per unit area?

But the nozel in kevin's pic looks much narrower

OK, I understand now. The thing is, my nozel is about 1/2 inch thick but it does not extrude a nice paper thin ribbon of the adhesive. It is much thicker, and the adhesive itself has a fairly low viscosity so it flows easy and quick. Kevins nozzle looks like it may extrude a thinner bead, but I envision still using the paintbrush to spread it around. My applicator could never be used to apply the adhesive directly to the fabric(for small seams) – way too much at once. That said, I've never used the nozzle Kevin is referring to, but I will be ordering one this week as it looks like the ticket.

Regarding the calculations. I looked over the spec sheet for the Hysol adhesive but it is really all over the place. Shear strength depends on all kinds of factors including current temperature, material it is bonded to, curing temperature…etc. The lowest number on the sheet is ~215 psi stated on bonding to pieces of nylon. It can go as high as ~1500 psi when bonding sandblasted aluminum. For me, this is plenty of strength for a tarp…and obviously overkill for this stuff sack :). If you need more strength, design your joints accordingly.

As for tarps, I haven't made any, but I have mocked up several seams to see the strength capabilities of each of the adhesives.

Here is my tarp tie out. I cannot for the life of me pull the stake loop off. I circled the area of failure. This is right outside the reinforcement area and actually rips the embedded cord inside the cuben laminite.

Below is an edge seam that you would find on a typical tarp. I think it may be called a french seam? Basically folded twice so that none of the cut/rough area is exposed. Bonded with the 3M tape and peeled back after about a week. Maybe I'm not using the 3M tape properly or maybe it's my superhuman strength due to my buff physique…either way I won't be using it again.

And here is a simple joint using the Hysol adhesive – one I would perhaps use on the ridgline to attach 2 pieces of cuben. The joint is in shear. There are no folds or anything fancy…this cannot be pulled apart no matter how hard I try. The material will fail first.

Hope that helps!

Love it. Pushing boundaries yet again. What was the weight on the pullout when the material failed (the bit you have circled)?

Fishing line is likely the ticket for a light drawstring. P-line flourocarbon is thinner and I assume lighter than standard mono lines. It also is not nearly so stretchy. Uncoated spectra might work given the spectra reinforcements in the fabric, but it also might slice through it as well.

Nia, I have no numbers for the test other then as hard as I can pull. I can only assume this will be stronger then any wind I would see on a tarp or other cuben product of this weight.
I should mention that the only reason the material failed is because I was holding onto only the tie out and the single layer material itself. In the field, this stress would be spread to the edge hems and perhaps would take a much greater force…I think anyway. :)
As for the fishing line, time to go to my local hunting shop to see what they have. Thanks for the ideas.