Cuben Fiber – Q&A

jonathan hauptman
(6hauptman6 – M) SUBJECT cuben-where to buy/how much $$$ ON 01/27/2006 15:45:47 MST POST REPLY
Anyone know where I can purchase the cuben fabric and how much it costs? I have some projects that I would love to do with this fabric, but I can not find it anywhere. I would really appreciate the input. Also any info. from those who have used this fabric for tarps and/or poncho tarps and packs would be helpful. How easy/difficult is this material to work with compared to silnylon and spinntex fabrics.

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POSTED BY
scott peterson
(scottalanp – M) SUBJECT cuben-where to buy/how much $$$ ON 01/27/2006 16:12:08 MST POST REPLY
Use the search function on this forum. There is plenty of postings compiled on what you can make and where to buy and so on.

Although at first it seemed like a great idea to me too, after finding that it costs $13 a yard, and $8 or so for shipping…it was not worth it for things like sacks and gloves and the like. That kind of money easily translates into bigger weight losses than .5 oz a yard on material for relatively small items…for me anyway.

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POSTED BY
Paul Kaercher
(paulkaercher – M) SUBJECT Re: cuben-where to buy/how much $$$ ON 01/30/2006 19:18:13 MST POST REPLY
I have made items from silk, silnylon, coated & uncoated nylon and polyester fabrics and
I found the Cuben fabric as easy if not the easiest
to work with.

Paul Kaercher

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POSTED BY
Jeff Dell
(skysappr ) SUBJECT Cuben question ON 01/30/2006 20:13:21 MST POST REPLY
Which cuben product do you use for what applications (pack, tarp etc)and what are the costs. Nailing this info down on the website seems to hurt my knuckles as I am draggin them around the site. You say its easier to work, with meaning it sews easier than ripstop and sil?

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POSTED BY
jonathan hauptman
(6hauptman6 – M) SUBJECT cuben?cuben?cuben?cuben?cuben? ON 02/24/2006 11:20:07 MST POST REPLY
On the cuben fiber website it sounds like i would have to order many yards(can not order just one yard). Is this true or am I just reading the data page wrong? I only want one or two yards of the 0.2oz. cuben for a pack project/stuff sacks/rain gloves. How much does the 0.2oz. material cost(someone wrote that the 0.5oz. cost $13 per. yard). Is the 0.2oz. weight accurate, or not? How waterproof/resistant? What about shipping costs? Etc, etc, etc, etc, etc…….

I don’t know about the rest of you, but I think we all need to nail down the specific details on this site/fabric. There is alot of scattered info., but I think we should try and consolidate it into one large forum post. What do the rest of you think? Any info. on anything to do with cuben fabric would be much appreciated.

Also, how much success has anyone had making packs out of this awesome stuff? Has anyone designed one with similar design to gossamer gear packs?

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POSTED BY
Charles Strusz
(infochuck – M) SUBJECT Telling folks to ‘search’ ON 02/24/2006 11:51:55 MST POST REPLY
You know, I’m all for directing people to use search fcailities for WHATEVER they happen to be after – asking a question without first searching is the height of laziness, and I detest it.

On top of the 20-post limit, it returns the 20 most recent, making the whole thing even more useless.

Of course, you can always use the ‘site:backpackinglight.com’ operator at google.

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POSTED BY
Jay Ham
(jham – BPL STAFF – M) SUBJECT NEW Re: cuben?cuben?cuben?cuben?cuben? ON 02/24/2006 13:54:27 MST POST REPLY
Jonathan,

Would you mind posting the link where you found the cuben material? I would like to take a look at it and see if I could sort out your questions. Without having seen the site, I will say that fabric manufacturers often have a minimum purchase requirement, making some fabrics very difficult to obtain in small quantities.

Jay
MYOG

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POSTED BY
Bill Fornshell
(bfornshell – M) SUBJECT NEW Cuben Material-Quest Outfitters Sells It ON 02/24/2006 14:13:52 MST POST REPLY
I have 2 threads with Cuben in the title located in the “Make Your Own Gear” part of the forum. There are about 6 pages of topics and you might have to look at more than just the first page.

Cuben fiber, how to get it and to to use it has been talked about so much here, but I do agree that you have to look to find it.

I don’t type fast and have gotten tired of typing and retyping the same info time after time. I think Paul and I are the only ones here that have done enought with Cuben to talk about it. I don’t count Ryan J.

I will start one more thread on the topic and do a cut and paste of as many posts that talk about Cuben as I can find. Then I will answer questions on that thread only as new information is available.

I called Quest Outfitters at
Quest Outfitters

Yes, they are selling Cuben Fiber but have not added it to their web site yet. It sells for $24.95 a yard. What they have is 54″ wide and I think it is the 0.44oz a sq yard Cuben product. You don’t have to buy a full yard. They ship almost always the same day you order it.

Hi Ryan,

Q – 1. How strong is the lightest cuben fiber?

Look Here

A -5. I agree. I want to see if I can make my pack top into a bag shape that will also be used for my gravity water filter and maybe even my food bag. It should be easy to use the water bag to wash what is necessary and maybe even me once in awhile. It really supports my goal to try and use everything for at least two funtions.

Cuben/Amigo H2O Water Filter Bag/Replacement

Cuben Rain Mitts

Cuben Pack – Page 1

Cuben Pack – Page 2

Cuben Footies/VBL

Craig Shelley
(craig_shelley – M) SUBJECT Sewing with Cuben ON 10/27/2005 21:17:40 MDT POST REPLY
I bought some of the Cuben fabric Bill Fornshell has talked about. I’ve started experimenting with sewing it. Bill or others, do you have any comments or suggestions on sewing it. My first project will be a tarp/poncho similar to my Integral Designs poncho/tarp. I have seen Bill’s posts on his tarp but I don’t recall any specific suggestions on working with this material.

I’m interested in types of stitches used, hem type used, methods to attach the guyline loops for best strength, etc.

Thanks. Craig Shelley

Edited by craig_shelley at 10/27/2005 21:21:58 MDT.

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POSTED BY
Bill Fornshell
(bfornshell – M) SUBJECT Sewing With cuben ON 10/27/2005 22:12:14 MDT POST REPLY
Craig, I would suggest you take a small piece of the cuben and play with it and see how your sewing machine likes it. I have a teflon foot that stays on my sewing machine. I have a home type sewing machine but it sews really nice. I use a medium sort of stitch and a medium length. I just sew with it like I do almost everything. Take you time, use good needles and thread. If your sewing skills are good you should have no problems adjusting to the Cuben.

Look at my Tarp pictures and you can see how I did my tie outs. Look at detail pictures of other tarps for more ideas. Make something small and see what it takes to tear it up. You will get some ideas from that.

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POSTED BY
Curt Presson
(Obdewla_X – M) SUBJECT Cuben Material ON 10/31/2005 20:20:06 MST POST REPLY
What is Cuben material… sail cloth? I’ve been able to locate silnylon fabric but where can you get Cuben?

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POSTED BY
jacob thompson
(nihilist37 – M) SUBJECT cuben ON 10/31/2005 20:23:14 MST POST REPLY
cuben fibre is the lightest fully water proof textile we ultralighters can get our hands on.

Cuben Fiber/Cuben Corp

Edited by nihilist37 at 10/31/2005 20:59:57 MST.

Hi Bill,

Thanks for consolidating all this cuben fiber info in one area, it really helps.

I do have a question I have not been able to find researching or searching the forums. What are your recommendations for seam sealing? Will something like silnet silicone sealer work for sealing the seams?

I hope it’s OK to post this here!

Thanks
Dan

Daniel this is the place for your question but I really don’t have an answer for you.

Seal the Seam??

I think since BMW sells the Stealth Nano Tarp they might have the best answer. Did you buy one of their Stealth Nano tarps? If yes you should feel OK asking them the question.

If Ryan J or someone from BMW has that answer would you please let us know?

Thank you.

Thanks for getting back bill.

I did not buy a nano tarp, just the size medium nano stuffsack which I plan to use for my sleeping bag.

I actually do have the question to BPL as a support issue item. It’s been assigned to Dr Jordan, but I believe he may be on his winter ultralight trip presently.

I’ll post here what I find out when I get an answer.

Cheers
Dan

Thank you Daniel, your question reminded me that I must seal my Cuben fabric tarp. I will be using Kenyon Seam Sealer 3 which is a water based urethane sealer.
I’ll let you know how it works.

I find that Scotch tape does a good job of patching
holes (I test punched holes to see how puncture resistant the fabric is) in the fabric. It sticks like crazy
to the plastic. Much lighter than duct tape and makes almost an invisible repair.

There is an old saying that you can tell the big guys form the little guys by the cost of their toys. I would say you can tell the SUL’er from the rest of the pack by the amount of Cuben in their gear.

If you buy a pack say a Gossamer Gear G6 from BMW and pay the member price of $90 do you worry about how much the material costs to make that pack? I don’t think so. I was able to buy about 20 yards of the same Blue material Glenn was using a few years ago and paid $8 or $9 a yard for it. I think it has gone up to $12 to $16 a yard. I say the same because Glenn told me where to buy it and what to ask for.

I own a G6 and made a pack just a little larger then the G6 out of Cuben Material. My pack took about 1.2 sq yards of material and weighed a little over an 1oz. I paid, with shipping etc, about $17 a yard for the Cuben material. It was the last of some they had that weighed 0.29oz a sq yard. What I ended up with was a pack much lighter and just as strong. Maybe stronger in some ways than the G6.

My investment in materials for that pack was about $21 for the Cuben material and a couple dollars for the Hardware. You might say I made a pack as good or better than the $90 G6 for about $25.

Do you think that a pack you can make that weighs as much as 2oz and costs $25 to make is to much money?

So I don’t leaving you hanging if cost is a real factor for you and I can say that at one time in my life it would have been a factor for me. Go to your local Wal Mart and ask a casher for a couple of there big plastic bags not the regular size. Go home and make a pack out of a double layer of the plastic from the two bags. It will work for awhile. Then made another, etc. If you have or can get on a sewing machine all the practice in making those packs will help you when you decide to move up to a higher cost material. My first ever SUL pack was made out of a two $0.25 – 5mil plastice bags. It weighted 2.8oz and was about 3400 cu inchs. No sewing required. I still have it and use it at times to prove a point.

Hi,

I’ve been using Cuben Fiber material (secretly) since late 2003. My first project was a Jardine-style tarp, which I taped together rather than sewed. I use a 3M industrial “tape” which is really not a true tape but an adhesive that comes with a removable paper backing (3M #9472LE). The advantage is no holes to seam seal (and it’s pretty fast compared to sewing). This approach is fine for seams that will be stressed in shear, but not usable for seams that are subject to peeling–I’m still looking for a really peel resistant adhesive.

I have also made a bag for my homemade external frame pack–it carries 40 lbs comfortably and transfers 90% of the load to my hips (which is why I made the thing in the first place). The bag weighs 1.3 oz with all the reinforcing I added–I carry 1.5L of water in each of the side pockets. The cylindrical main bag is 11×42. The pack itself is about 18 oz. Belt and straps are not made from cuben, but from 2.0 oz/yd nylon which I find breathes enough that’s worth the tiny bit of extra weight. Pack frame is 1/2″ aluminum with .028 wall, weighs 4.6 oz.

I have dry bags that are about 11×24 that weigh less than an ounce. My groundcloth is also cuben (expensive ground cloth, but sturdy and patchable). It also functions as a “skirt” during times of heavy rain.

P.S. someone mentioned patching their tarp with scotch tape. You might want to test this with water–last time I checked, the adhesives of all “office supply” type scotch tapes were water soluble!

Hi Steve
I too made a bag (dacron sailcloth) using taped seams. I agree with your assessment of tape with regards to shear vs peeling stresses. However I found that on a hot 2 day hike (80+ degrees f.) the seams subject to shear stress creaped. On a longer hike they probably would have failed.
Just something to watch for.

How did you seam your tarp, overlap with a single strip of tape, or did you fold it using 2 or more strips of tape?

P.S. What are you using to patch your Cuben fabric? I just put a scotch tape patch on a piece of Cuben cloth and placed it in a glass of water. I’ll let you know how it holds up.

Steve,
I copied your idea for 3M #9472LE to the Materials Sourcing thread in MYOG. Hope you don’t mind.
Vick

“My investment in materials for that pack was about $21 for the Cuben material and a couple dollars for the Hardware. You might say I made a pack as good or better than the $90 G6 for about $25.”

Bill, it seems you captured a retail for Cuben that no longer exists. So if your pack took 2 yards, that would cost you $42 (shipping incl.) from the Cuben source, or $50 (plus shipping?) from the other retailer mentioned in the thread. Obviously this is not a tremendous amount of money for a pack given retails for factory made ones (plus the obvious pride one can take in their own creations), but I still think marking Cuben up $11 or charging $14 to ship something that weighs next to nothing is gauging you self proclaimed “big guys” out there. Me being a little guy, I have found that even in purchasing most of my UL stuff prefabed…it is still less money than going to REI, et. al. and buying something from a big name. So to your point, there are a lot of UL options out there and a lot of those are less expensive.

I would only suggest you consider condesention un-neccesary in this forum. I think we all appreciate your wonderful design contributions and learn a great deal…but individual perspectives are based on a lot more than just a % of time dedicated to making light gear or a constant persuit of shaving every fraction of a gram from your kit.

I used two widths of 1/2″ wide tape for a total width of 1″. I overlapped (no folding) the cuben material so when finished there were three layers: cuben, tape, cuben. The seam ran longitudinally and formed the ridge of the tarp.

The tarp has withstood some fairly ferocious overnight winds. Before I entrusted myself to the tarp, however, I made a loop out of a strip of cuben, using several inches of adhesive, then hung a 50 lb bag of gravel from it for a week. There were no visible changes.

Dacron is a different beast; I’ve never used it for things like a tarp because (compared to cuben) it supposedly stretches more. I suspect tapes wouldn’t stick to it nearly as well as they do to the polyester film, but I have no data on that. Paul: what tape were you using?

The 3M tape is supposedly resistant to all common chemicals (including alcohol), withstands reasonably high temps (anything you’re likely to personally experience), sub-zero temps, etc etc. It’s darned expensive, though.

Re water solubility of Scotch brand–it’s weird: if you stick some to itself (sticky side to sticky side) it appears to be impervious to water. But if you attach it to cuben (or other polyester film, e.g., space blanket) it turns slimy in a few hours.

For patching pinholes, I just use a bit of duct or similar tape. For a larger area, say, one with many holes, I’d just outline the area with the 3M tape, then attach a second piece of cuben over top. I’m not proud :-)

Vick: no problem with posting my idea to the Materials Sourcing thread….

The tape I have is 3/8″ wide from Kitebuilder.com
it is 3M 9460PC

The dacron sailcloth has very little stretch.
The taped seams did not hold well in the heat.
Perhaps the finish on the cloth is the problem.
In any event, I’m glad to hear that there is no
problem with it on the Cuben fabric.

My scotch tape (Scotch -Magic tape) test so far is
8 hrs in a glass of water. Still sticking tight, I can peel it but can’t slide it around on the fabric.
I will let it go 24 hrs, let it dry and then repeat
the cycle.

I like your tape patch idea.

My Cuben Poncho/Tarp used the 3M tape on the head opening and on a few stress free places on my Cuben Pack.

There is a better glue but it really needs a special glue gun and the glue gun cost $1600 more or less.

Steve, Why don’t you post a few pictures of your Cuben projects. I am a “show me” kind of guy.

all this tape has got me confused, dose it work better than sewing?
for some reason I would’nt trust it.

if you were to sew, what kind of thread would you use?

Bill: I’ll try, but I’m pretty busy getting ready for my ’06 PCT thru-hike. No promises, but I’ll try.

Paul: I looked at the 9460PC but I noticed a comment that said it would creep under sustained load. When I hung my bag of gravel to test the 9472LE, the temp was about 70F, so I don’t know whether it would creep if I pitched the tarp in the desert sun (which I don’t plan to do).

Re the water test, I tested my Scotch Magic tape with a piece of mylar which *should* be the same as the cuben film, but perhaps isn’t. I’m now repeating the tests with actual cuben–if it works, then my patches will look a lot nicer!

Ryan: My personal view is that for *some* things, taping is better since it doesn’t leave holes that have to be sealed. Other times, like when I attach pockets to the bag, sewing is better because the stress will cause them to peel off the pack (eventually).

It took me a while to trust Cuben material let alone tape–the stuff is just so flimsy feeling it takes a while to believe it will hold anything. Same with taping–you should have seen me hanging that bag of gravel; I let that sucker take the weight *very* gradually and made sure my feet weren’t anywhere close to where it would fall because I couldn’t believe some tape could withstand that load. But it does.

Here’s a question for you all: what the heck do you cut your cuben material with? I’ve tried various types of scissors without much luck–I currently use a razor blade with a piece of poster board (cardboard) underneath the cuben material; sometimes takes several passes to cut all the fibers.

From Scott posted:

S – 1. Bill, it seems you captured a retail for Cuben that no longer exists.

Reply – 1. Cuben Fiber, can as requested by sailmakers, make a lot of different fiber products. They don’t seem to carry much of a standing inventory. When I first called and talked to them I asked about their lightest products. I was sent 5 samples onre of which weighted 0.29oz a sq yard (36″ by 36″). I called back and asked about this item. I was told the inventory showed a small piece maybe a couple of yards left over form something. They would look for it and call me back. After a short time I got a call and was given a price. I said send it. I also asked if they planned to make any more of that weight. They said only if they got a big order form a sailmaker. This piece was the first Cuben I made anything out of. I used if for my pack and my Gravity Water Filter.

My second order was the 0.44oz product and I received it in about 2 weeks. This was fine for me. Over the few years I have been using Cuben I have gotten about 38 yards from them. In my inventory at this time I have enough 0.29oz to make one or maybe two more packs the size of the first one. I have 0.35oz and 0.44oz.

S – 2. So if your pack took 2 yards, that would cost you $42 (shipping incl.) from the Cuben source, or $50 (plus shipping?) from the other retailer mentioned in the thread. Obviously this is not a tremendous amount of money for a pack given retails for factory made ones (plus the obvious pride one can take in their own creations),

Reply -2. You may recheck and see that I said the pack took about 1.2 yards of Cuben not 2 yards.

S – 3. but I still think marking Cuben up $11 or charging $14 to ship something that weighs next to nothing

Reply 3. I am not sure how Cuben charges or why. My experience seems to show that they have a handling charge that may be fixed per order. When I order a panel (about 9 yards) I pay one amount plus postage (UPS or what ever) .

S – 4. is gauging you self proclaimed “big guys” out there. Me being a little guy, I have found that even in purchasing most of my UL stuff prefabed…it is still less money than going to REI, et. al. and buying something from a big name. So to your point, there are a lot of UL options out there and a lot of those are less expensive.

Reply – 4. Your level of understanding of what I said seems to leave a lot to be desired. It is an “old saying” sorry if you have never heard it. I am however “a self-proclaimed SUL-er”. The reference:
“There is an old saying that you can tell the big guys form the little guys by the cost of their toys. I would say you can tell the SUL’er from the rest of the pack by the amount of Cuben in their gear.”

That reference is to all the gear being sold now or planned for the future. You use the word UL, I used the word SUL. Big difference between SUL and Ul and I don’t care how many UL options are any where. My point or my statement has nothing to do with UL. Get you facts correct.

S – 5. I would only suggest you consider condesention un-neccesary in this forum.

Reply – 5. Thanks for your suggestion.

S -6. I think we all appreciate your wonderful design contributions and learn a great deal…but individual perspectives are based on a lot more than just a % of time dedicated to making light gear or a constant persuit of shaving every fraction of a gram from your kit.

Reply – 6. I guess you just have to take the good with the bad.

S – 7. “I’ve been using Cuben Fiber material (secretly) since late 2003.

Reply -7. Very interesting. Tells me a lot about you.

Steve and others, I use a hobby knive such as an X-acto with a new blade. I cut it on one of those green mats with a self healing surface. They sell them at Wal Mart and other places. One pass and it is cut.

Bill-

The true definition of “UL-er” and “SUL-er” still eludes me…and is really not that important to me. I did not intend to invoke a negative reaction and was not seeking an apology or a rebutle.

I realized your pack only took 1.2 yards, but to my limited knowledge, you cannot buy it that way. At least not from the Cuben guys.

My only point was that it is currently a challenge to get at the damn stuff, and if you consider it only saved you (1.2 x.44) .76 ounce over (1.2 X 1.1) ripstop…I suppose that is what SUL is. I will have to live with the fact that in your opinion, guys like me are “the little guys”. It wrankled me this morning thinking about what it would be like going on a hike with you…and if your abilities on the trail and in the field would leave me as in the dust as your design and fabrication does…and the bottom line is probably not. I got into lightening my load to make enjoying nature and my time spent there as great as possible. I don’t even want to spend a great deal of time evaluating the stuff past “is it working as expected”, once I get out there.

I do however find your fevered pursuit of lightweight effeciency and the designs it spawns fascinating. So I will, as you say, take the good with the bad, and stand outside the circle and watch quietly from now on.

And I have not used Cuben fiber “secretly” or otherwise…that was another Peterson…and what that tells you about him I not sure. It would be different than you, seeing that you openly share everything, but being different is not bad, right?

Something happened and I posted this without knowing it.

Scott Peterson:
I am sorry I was confused and wrong. I kept trying to go from one open window with the thread on it and another window where I was trying to write a reply. I keep thinking I was wrong but I just didn’t get it right. Old age maybe.

I don’t know where the line is drawn between UL and SUL. I have moved myself to the next lighter term and I call it (for myself) Hyper-Light. Why go there, because I can??? maybe. It is a challenge and some of what I am doing can be done with other material. I don’t use Titanium for my External Frames anymore because my aluminum is almost as light and a lot cheaper and easier to work with.

I don’t mind a negative reaction, good ones cause me to stop and rethink things.

You are correct to get 1.2 yards for a project I think you would need to buy 2 yards.
The 0.29 oz stuff was a short piece and I don’t think I paid full price for it. What I also said somewhere about that first pack was that I could now make another one at about 1 oz. My search is for lighter parts that are made for other things that I can use to replace stuff we now us. I now have some hardware, strap and webbing material that is really super light. That stuff will be used with regular material such as the you talked about. I have a bunch of the Blue spinnaker material like the G6 is made out of and I have heavier material for packs that I will try at some point.

Getting the Cuben for me has gotten almost easy. I do buy it now by the panel which means I buy about 9 yards at a time. I made one order of 2 panels which was about 19 yards. I talked to Chris once about the perception that they were not consumer friendly. He said they just are not setup for orders less than a panel. They will sell small amounts and are trying to make it smoother. For now we are a really small part of their market. At one time Ryan J was asked about selling some of his Cuben to us by the yard. He said he could but he would need to get about $19 a yard for it.

Scott, “the little guys” this was a joke. All my life I have been around people that wanted the biggest and best of what ever they were into. I never had the money to keep up with them even if I wanted to. I could however make some of my own stuff that was at least up to a lot of what they had. The saying “you can tell the men from the boys by the costs of their toys” was always a funny one to me. My toys were in a lot of ways just as good as their toys but I made mine and they didn’t cost much. What I was saying or implying was that money will by you the SUL toys and more and more of it will be coming on the market. Or we/you/me can make some of our own SUL gear and saved some of the money it would cost to buy the really light stuff.

Please don’t stand outside “the circle” you words. The more eyes that look at something the better it can get.

If I can figure out how to make something really light and post it so others can try and make something similar if they want, we can have stuff cheaper than buying it.

You might ask why am I doing all this work on making light gear and so on. I can not hike, I can’t really be away from home right now and have been more or less grounded from outdoor activity since October 2004. I had cancer, no big secret, it is dead but my recovery is still ongoing. From the first, working on gear design and making prototypes has been a big part of how I coped with cancer and that carried into my recovery therapy. It kept my mind off other things and the more gear I made the lighter I was able to make things. It was fun. It gave me a reason to get up everyday and stay away from the TV. I don’t know when I will get back into the woods but I really think that day is coming closer.

I enjoy nature and hiking for me is not a race from camp to camp. It will be fun to see if the things I have made will work on the trail.

I don’t have secrets. I do however want to make sure things work before I say to much about them. I was a little surprised when the other “who-ever” announced he had been making stuff out of Cuben material for a long time. Paul and I have talked about what we are doing in making gear for a long time, almost weekly. It is nice to share thoughts back and forth and ideas can move very fast that way. So I guess I was surprised and a little disappointed that someone had been lurking out there for such a long time that was making stuff out of Cuben also.

Anyway some might say this has dragged on much to long. Sorry, not really.

OK, I think I have a better handle on this. In my earlier testing, I left a bit of the scotch tape hanging “free” (not pressed down on the mylar/cuben). In this configuration, the tape is very easily pulled away from the material with only a couple of hours of soaking.

However, if you press the tape down so that all edges are securely adhered to the material, it seems to last overnight (at least). That is, the edges seem to be very securely stuck to the material. But if you then pick at a corner and get a tiny bit of the tape loose from the material, the whole piece of tape will peel up very easily. In my case, the adhesive stayed stuck to the material and the tape itself came unstuck from the adhesive.

I tested this with both cuben and mylar (space blanket) and got identical results. Why it behaves this way is beyond me. In any case, I don’t think I’ll be using Scotch Magic tape to patch holes (though others may not find this result bothersome). I certainly wouldn’t use it for anything “structural” (not that anyone suggested it).

Further thought: there is that ugly brown packing tape which seems to stick pretty well to most things. There is a clear version of that which might be more waterproof than the Scotch Magic tape. I may pick some of that up and try it.