Jan 9, 2012 at 10:19 am #1283898
What is Cuben really? I guess it is two sheets of plastic with some kind of mesh in between. Could you make a redneck version of this with some kind of thin plastic, some kind of screen, glue it all together with some kind of glue?
Maybe I am nuts but I am thinking about that window film people use for ground cloths, that or maybe the thinnest painters drop plastic with some kind of mesh material in between. Not sure what you could use for glue.
The idea would be to make a cheap tarp that was made of plastic (100% waterproof) but would not stretch and tear like a painters drop cloth.
What is "spectra" exactly?
Thoughts?Jan 9, 2012 at 10:23 am #1822164
I would start here:
Maybe lay up some dental floss between the layers? Either way, I highly doubt you are going to end up with anything very light.
Just use some 3mm dropcloth with duct tape reinforcement if you are feeling cheap.
JayJan 9, 2012 at 12:34 pm #1822220
I was thinking more along the lines of some sort of screen or fiber that is in sheets.
That plastic bag thing is kinda cool. I imagine something that thin is what would be needed for redneck cuben :)Jan 9, 2012 at 1:04 pm #1822238
@hhopeLocale: East Bay
Ace Hardware sells rolls of that mylar like polypro like sheeting, as far as I can tell, it's pretty close to identical to the layers of mylar that cuben uses. Feels exactly the same, though of course the chemistry might be a bit different.
It's about 11 a roll
5069190 part number, 62" x 25 feet.
Also useful to make polypro like ground sheets like Gossamer gear sells, as far as I can tell the stuff is the same.
I tried to make a backpack rain cover for a small pack with it, the only thing that didn't work was the glue, I used contact cement, which is too sticky and I couldn't let it dry on both sides because the film curls up, so I need to redo that, but it held the 1/16" elastic I got from zpack in the cord channel, and it didn't rip, and seems quite strong, except for the bad glue job.
I actually got that for similar reasons you are thinking here, to see what a super thin film actually is like working with, before touching cuben or anything expensive, but I think it's strong enough on its own to use for things like ground covers and backpack rain covers, and weighs basically nothing. I used silnylon to reinforce the area around the holes for the draw stringed elastic, which hooks under the backpack straps, I'd use cuben there I think once I get some.
Not sure what glue to use, contact cement I won't use again, I need something that I can apply and bond right away, shouldn't be hard to find.Jan 9, 2012 at 2:16 pm #1822280
Interesting on the mylar sheeting in rolls. Sounds like a promising lead.
What about superglue for the glue? Might make it brittle. I have seen some MYOG stuff for cuben and I think they use superglue to put layers together.Jan 9, 2012 at 2:37 pm #1822287
> The idea would be to make a cheap tarp that was made of plastic (100% waterproof) but would not stretch and tear like a painters drop cloth.
As they say, "Been there, done that." Works like a charm but there are a few things I'll change when I make Rev B. See my comments I just added to Part 2 of the video.
Oh, and I also plan to try one with polycro instead of LDPE. Not very private but it would be lighter since you shouldn't need much tape. You could also do it with one piece (sliding door size). I'm guessing I'll need to pre-shrink the polycro somehow.
BTW, this is nowhere near as strong as cuben. However, for your desired application, you don't need cuben.Jan 9, 2012 at 5:27 pm #1822352
Colin KrusorBPL Member
@ckrusorLocale: Northwest US
If your aim is to make a slightly stronger (albeit heavier) version of painter's plastic, you can definitely do that. I've done it by using a heat gun (looks like an industrial hair dryer) to heat two sheets of polyethylene painter's plastic with a network of nylon fibers (monofilament fishing line) in between. The finished laminate looked a lot like the clear, fiber reenforced tarps sometimes used at construction sites. It wasn't very strong (the fibers tended to pull through), but it was stronger than the painter's plastic alone.
The reason backpackers (or sailors or windsurfers or kite flyers, etc.) get excited about cuben is that it is stronger per unit weight than woven fabrics (like polyester spinnaker or silnylon). You won't be able to make anything yourself that is stronger per unit weight than cheap nylon fabric, so it might not be worth it.
The cuben used for backpacking shelters/gear contains UHMWPE (Ultra-high molecular weight polyethylene, ie Spectra and Dyneema) fibers that are sprayed with urethane adhesive and sandwiched between sheets of mylar (polyester film). Typically the mylar is 0.08 mil (thousandths of an inch) in thickness. This is less than 1/10 the thickness of the thinnest film you'll find in a hardware store. It is less than 1/5 the thickness of a space blanket. That is one of the problems with DIY cuben: you need large sheets of extraordinarily thin film.
The UHMWPE fibers have a tenacity (strength) of about 45 grams/denier (don't worry about those units). Kevlar has a tenacity of about 30 grams/denier, and the strongest ballistic nylon fibers have a tenacity of about 9 grams/denier.
So, given your heavy film and weak reenforcement, your DIY cuben will probably be much heavier, much weaker, and more expensive than plain old coated nylon from a fabric store. I've heard that Walmart sometimes has lightweight coated nylon fabrics for $1.00 per yard. I know you can buy it online for less than $3.00 per yard. Those seem like better options.Jan 10, 2012 at 10:17 am #1822661
In addition to what Colin listed, the Spectra fibers have been plasma bombarded which serves to significantly raise their surface energy and thus their interaction with adhesives and other plastics. It is unlikely that you will get anywhere near the bond strength between fiber and film without this step. Yet another reason why a DIY version is likely to be significantly inferior to the admittedly expensive commercial product.Jan 10, 2012 at 10:21 am #1822663
Dan DurstonBPL Member
I wouldn't want to try making this stuff. Not to be a downer, but it's hard to imagine this turning out as anything other than a time consuming project that winds up saving no weight.Jan 10, 2012 at 12:50 pm #1822760
I'm not saying you could get the weight/strength on par with Cuben but maybe you could create something stronger than a painter's drop cloth and 100% waterproof unlike sil nylon for cheap by applying the same principal as cuben…the idea of sandwiching some kind of mesh with two thin layers of plastic.
Maybe the idea that two 1 mil sheets of painter's cloth with a 1 mil mesh glued in between would be stronger than a 3 mil drop cloth. I see the mesh in between kind of just taking away the 'taffy' like nature of straight plastic.
This stuff http://gossamergear.com/shelters/polycryo-ground-cloth-large.html is .5oz/sq yard. If you had something half that thickness so it was .25oz /sq yard, a thin mesh that came in sheets or rolls that was the same you would have .75oz/sq yard plus the glue which could be dispensed in a paint gun. Maybe that window film people use?
The thing I don't like about sil nylon is it is not 100% waterproof (misting) and it absorbs water weight.Jan 10, 2012 at 12:54 pm #1822765
This is the stuff you mentioned….
I wish I knew the weight. If it could be used along for a ground cloth it's probably too thick.Jan 10, 2012 at 1:18 pm #1822782
Should be very close to GossamerGear's specs: 2.7 oz. (77 g.) for 72 x 96 in. (183 x 244 cm.) My guess would be it's about 1 mil thick.
Looks like from other's posts that DIY cuben is not at all practical. However, making a reliable shelter from 1 mil LDPE (eg, Heatsheets) is very practical per my above post. It should also work for polycro, perhaps even better since there's far less inherent stretch. I'd prefer using the GG piece above than the roll from Ace so you wouldn't even have a seam. Making a 6×8 flat tarp at ~5 oz (tape is heavy) for maybe $11 in materials (unless you already have the clear duct tape) is hard to pass up. I have a 7×10 piece from a Duck large window kit I found in Walmart.Jan 10, 2012 at 1:18 pm #1822783
Let's ignore my intended use. I don't want this thread to be about tarps or tents or the best way to make either. I want to discuss making a cheap/redneck version of cuben. The idea being to end up with something light weight and 100% waterproof that does not stretch like plastic.
(Although Michael, I watched your videos and I like your MYOG tent a lot).Jan 10, 2012 at 1:28 pm #1822792
Edit: ignore this post then. Typed it while you replied.
I guess what I'm trying to stress is you don't need a full mesh layer to accomplish what you want. Unless you are very rough on your gear, what I did meets your requirements. If you actually watch my video, you'll see where I had to patch it up with duct tape where my dog got her leash caught in my guylines and tore it up and bent the trekking pole nearly 45 degrees. I still took it on both big trips, which included storms and hail. 100% waterproof. I would NOT use painter's dropcloth for this – not the same material though it acts similarly. I also doubt it has the UV resistance.Jan 10, 2012 at 1:45 pm #1822798
Originally this idea came from thinking about cuben versus say painter's drop cloth. I am just curious what could be achieved by sandwiching some sort of mesh between some sort of plastic sheets…basically bumming the principal of cuben to possibly achieve something stronger than, maybe lighter then?, maybe the same as but stronger than any kind of plastic you could pick up. Maybe something could be achieved, albeit not on par with cuben, but using the idea behind cuben that can't be achieved with any impregnated cloth or any plain sheet of plastic.
I don't like the idea of using floss or mono filament fishing line. I don't like the idea of using something that would have to be laid strand by strand. I was thinking more along the lines of some kind of mesh or screen that would come in sheets. Maybe use some kind of glue in a paint gun, spray it, sandwich it, maybe have a couple seconds to work out the wrinkles.
Yes, I see from the previous posts that cuben is certainly the pinnacle of light/strength and it's not possible to replicate by individuals. But what if you could make something say that was 1.1 oz/sq yard (comparable to sil nylon) that was cheap (using $11 per roll type materials), that was 100% waterproof like a painters tarp, but much stronger? Heck I don't know I'm just throwing it out there.Jan 10, 2012 at 1:58 pm #1822806
Your best bet will be using polycro for the layers then. Cheapest, lightest and strongest stuff I know outside the other common materials. I have no idea how you'll make an effective and lightweight mesh layer or bond large sheets together without wrinkles/bubbles.
You really need to specify a use to get practical ideas I think. For example, why would you need to add mesh for a quilt or some stuff sacks – polycro is plenty strong enough already. However, I don't know if you can glue polycro like you can cuben. You wouldn't be able to sew it like cuben without mesh or tape and the tape makes it a major pain (gums the needle). Maybe it could be sewed with a thin strip of silnylon between the sheets?
Polycro itself stretches very little in my subjective tests, very close to mylar. It can shrink in sun though so you'd want to pre-shrink it. Not sure if oven or dryer would work. I haven't even looked up what temp is needed. Just know that hair dryers are what is normally used. :)Jan 10, 2012 at 2:26 pm #1822817
@hamericaLocale: Northern Virginia
Ok, I'm really not sure what the point of this exercise is but I'll play along. What about layering and then sandwiching fiberglass packing tape? I doubt it would be very light in the end but it would be pretty strong and half the work is already done for you. Or even easier you could just put a layer over the polycryo.Jan 10, 2012 at 3:02 pm #1822831
I sure like the idea of using polycro as the film layers since it is impressively light, has great abrasion resistance, and great puncture resistance. Its major drawback is tear strength but a well bonded mesh should eliminate that concern. I wonder if there is some sort of 1 mil double-sided tape that contains fibers for reinforcement.Jan 10, 2012 at 3:17 pm #1822838
Colin KrusorBPL Member
@ckrusorLocale: Northwest US
I think several limitations are clear:
1. Light urethane coated nylon is available for about $3.00 per yard. You won't be able to make anything cheaper than that.
2. Light urethane coated nylon is very waterproof (more than silnylon). DIY cuben won't beat it in that respect, either.
3. Light urethane coated nylon is much stronger than any laminate of a similar weight that you could make at home.
If you just see the DIY cuben project as an interesting challenge, and you don't have any intention of producing a material that is competitive in any respect with other available materials, you then have the freedom to try all kinds of things. You could apply the thinned laminating adhesive with an airbrush or spray bottle, and use light silk (0.5 oz/yard), nylon or polyester veil material (ie "tulle", 0.7 oz/yard), nonwoven kevlar (0.4 oz/yard, from composites suppliers), nonwoven nylon (0.3 – 0.9 oz/yard), nonwoven polyester (0.4 – 0.9 oz/yard), nonwoven polypropylene (0.3 – 0.9 oz/yard), or nanoseeum netting (0.7 oz/yard). Some of these stretch more than others, and none are very strong compared to woven nylon fabrics, but they are stronger than painter's plastic or Heatsheets. For the film you could use generic clear mylar, space blankets, Heatsheets, painter's plastic, window film, urethane or nylon vacuum bagging film, etc. The Heatsheets, painter's plastic, and window film won't stick to the glue well, but weak adhesion might be enough. Post your results if you decide to experiment.Jan 11, 2012 at 3:06 pm #1823436
What about Tyvek? Not the house wrap but the thinner Tyvek that they make their lab coats with. I can get as many as I need at work in the size of 4xl. I'll try sewing a couple pieces together reinforced with a few pieces of nylon tape. The tape is fairly heavy but you can't tear it, it has to be cut with something very sharp. Strips of 1 inch wide, not in between the layers, but on the opposite side of the load. Even stripping the tape down to 1/4 inch strips with a closer spacing would give incredible strength.
What would be a good standard size for weight and strength? I think we could definitely come up with something if we had a good way to compare what we each create.Jan 11, 2012 at 3:41 pm #1823460
drowning in spamMember
The problem with trying to use your own mesh is that it's way too strong along the threads, and it's not spread out. This is the advantage. Cubictech was able to spread the spectra out thinly to even things out. I admit that I'm tempted to try to do something like this with the boxes of carbon fiber and fiberglass tow that I have, or maybe the big roll of fiberglass mesh, but I would never be able to spread it thin enough to find a good balance of distributed strength and weight.
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