Polycro Tarp Tested!

[David Gardner]

I don't hem them at all anymore.

[Michael Ray]

> BTW, I have stopped using nylon sail repair tape after several of the tie-outs let go.

Good, I was wondering if I'd done something wrong. LOL. I will use longer pieces next time to get more surface area since I much prefer the nylon tape to the tough duct tape, but it doesn't seem to stick as well. It's so much lighter that I can use a lot more though.

I like your new ends, but the duct tape is a major PITA to sew through. I'd guess the sail tape is easier though the adhesive will likely still gum the needle eventually.

BTW, the Duck brand patio door kits are 7×10. They are meant for indoor installation, of course, but I'm not sure if that affects long-term durability. I got mine at Walmart on off-season clearance.

[Mike Megee]

I've been following this thread for about a month and finally got around to making one. I used Frost King Stretch Window Kit the outdoor version. Hoping it might be a little thicker than the indoor version.

http://www.amazon.com/gp/product/B000JINIZ2/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

Did a few things a little different than what I‘ve read on this thread. For one I used filament tape instead of sail repair tape or duct tape.

http://www.amazon.com/gp/product/B00DVB7VT8/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1

It seems to stick to the film well. So far so good. I used a semi flat shock cord as guy out points on the long sides (three feet from each corner) and ran the filament tape the full length of the ridge line instead of using a cord on the ridge line. Instead of taping a washer on the guy out points I used the filament tape to tape a light weight 1/2" strap on each corner and on the ridge line. The weight for the tarp itself without guy lines is 5 ounces. 10 stakes weigh 4 ounces. So I’m hoping that the entire tarp kit will weigh less than 10 ounces. The tarp kit will include tarp, guy lines, stakes, and ground cloth. I've set it up at my office because it's raining freezing rain outside right now. I’m going to leave it up overnight and then set it up outside tomorrow. I'll post some pics then.

[Dale Wambaugh]

I like the filament tape idea. I'm sure that tape distortion is a major factor in failure. The filament tape should do well with linear stresses.

I've wondered about indoor and outdoor films. The thickness is usually labeled on the box. Other than thickness, one assumption is that indoor film MIGHT be less UV resistant, but my first thought is that the tape packaged with the film is easier on indoor trim finishes.

[Mike Megee]

The great thing about filament tape it has no (or at lease very little) stretch. So I could make the ridge line pretty taut. I have put some thought on the UV problem not only on the film but the tape. I've come to the conclusion that it might not be as important as I first thought, because being from Oklahoma with lots of bugs in the spring, summer, and fall I will probably just use this tarp during the winter and since winter has such short days I will be hiking most if not all of the daylight hours so the tarp will see very little daylight.

[David Gardner]

Mike,

Would love to see pictures, especially your tie-outs. Please let us know how the filament tape holds up to weather long term.

[Mike Megee]

Put the tarp up this afternoon in 15 to 20 mile an hour wind. The weather guessers say it should get down to 18 tonight. Going to be sleeping in the tarp tonight trying out a new sleeping and seeing how well esbit tables will make coffee when it's this cold. Took some pics but I'll have to relearn how to post them. Will do that tomorrow. Watching Ok State play Baylor right now. Priorities, priorities. :)

[Mike Megee]

Spent the night under the tarp last night. The only problem I had was with the string I used. The taut hitch kept slipping. So need to change out guy lines.
Here are some pics.

[Mike Megee]

Don't know why these did not load on the previous post. Hopefully will this time.

[Mike Megee]

[David Gardner]

I like the tie-out idea. Interested to see how much load they can bear. Any idea how many pounds of force are on the ridge line tie-outs when pitched? I have used a linear pull scale and measured 25 lbs. the way I pitch mine. I may tie the scale into the stake end of a ridge tie out cord to see what kind of force it has to resist in windy conditions. We had strong winds here the past few days with gusts to 50 mph but it's calm now so will have to wait on that for the next storm.

However, the winds were strong enough that my latest un-hemmed tarp experienced two tear failures at the edge of the tarp near tie-outs. So I'm going to try hemming again, but not with the tape that comes with the Frost King window kits. Even with the "exterior" window kits my experience has been that the double sided tape in the kits does not hold long-term, esp. in cold and wet conditions. Don't know if it's just the tape that comes with Frost King kits, or a generic problem common to all kits. Will try Duck brand and 3M kits, but have also ordered some hi-tack tape from Uline to see how it works. Someone told me they had tried super glue on the hems, so may try that too.

[Mike Megee]

I just checked the tarp and had three tie outs failed. One on a corner and two on the sides. The strap and shock cord just pulled out. Have shock cord as side tie outs. The tape did not fail nor did the tarp. The corner tie out that failed is the one in the picture which is the only corner with that kind of material. The both ridge line tie outs and the other three corners have the same half inch strap and non of those failed. I ask my wife if she had the half inch strap that did not fail and she handed me some hem tape. Looks similar not sure if it is as strong. Will give it a shot and see.

David what kind of guy line are you using? Mine won't hold a taut hitch. Need to change it.

[David Gardner]

Mike,

I use bright yellow 1 mm Spectra 150# cord that I get from Ultralight Designs:

http://www.ultralightdesigns.com/products/shelter/guyline-150.html

Don't know how well it will hold a taught line hitch, but Ultralight Designs also sells micro line adjusters:

http://www.ultralightdesigns.com/products/shelter/microLoc.html

There have been several threads here on BPL about tarp cords and knots. There are several knots besides the taut line hitch mentioned there. One is called the trucker's hitch, which is easy to release/untie:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=3870

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=12156

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=84333

Also see:

http://andrewskurka.com/2012/tarp-guyline-system/

Ultralight Designs also sells orange 2 mm Spectra 300# cord, but it's total overkill.

(No affiliation with Ultralight Designs.)

[Mike Megee]

Thanks David I'll give them a look.

[Michael Ray]

> I just checked the tarp and had three tie outs failed. One on a corner and two on the sides. The strap and shock cord just pulled out. Have shock cord as side tie outs. The tape did not fail nor did the tarp.

I was going to be really surprised if those had held. I'd recommend making a loop with the tape and then tying a loop of shockcord onto that. Because I was using shockcord, I never used hitches to tighten the pitch. If I couldn't find a stake point with my normal line length, I'd just make another loop with a bowline to shorten it.

[Mike Megee]

Thanks Michael I'll try that. We are getting ready to have some cool weather not sure if it's going to be windy or not. So it might be a while before I can give it a good test and I'm wanting to replace the guy line also.

[Michael Ray]

You could also use the washers, of course, but I got the impression you were against those for some reason. Strapping tape should be fine though. I have used the transparent duct tape with success.

[David Gardner]

Just found Duck brand polycryo in 7' x 10' size, 1.4 mils thick:

http://www.amazon.com/gp/product/B00G801FVO/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

The kit says it's for indoor use, so I wouldn't trust the double-sided tape that comes with it for hemming the edges of the tarp. I have ordered a couple of the kits and will provide more info after it arrives.

[Michael Ray]

The Duck kit is what I use. $4.50 on spring clearance at Walmart. :) Probably won't get that lucky again.

[David Gardner]

That is a fantastic price! It's $27 and change from Amazon. I just checked my local Walmart but they don't carry it, so I ordered a couple of kits on line at Walmart.com. Even at non-clearance prices, it's 1/2 the price of Amazon, and since I will pick it up at the store there is no shipping cost either. Thanks for the great info!

[Anonymous]

Has anyone tried Tvyek tape with cross linked polyolefin films?

That's what i used on the tarp i made recently. I used the tyvek tape for the guy/tie out loops, and for taping SOL heat sheets to the inside.

Sat. night on the AT near SNP, got down to around 22 degrees F and got moderately windy at points, and the tarp held up fine at least on this trip (previously left it out in the yard for a few days as well). Used the 7X10 foot, 1.2 mil thick stuff from Ace hardware. *

I've also thought about combining "polycryo" with Argon nylon fabric since it's relatively cheap and light to really increase strength and long term durability. I would fold over excess Argon fabric on the edges of the polycryo and sew, and use that doubled up edge for the tie outs. If going this route, i would probably use .7 mil or.6 mil thick polycryo to keep down weight.

I really like the idea of double walled stuff at not much weight or price addition, but the nylon fabric inner will add significant tensile strength. Yes, it costs significantly more than plain polycryo.

*this tarp was originally meant to be a 1 person semi pyramid, mostly closed type winter shelter, but i didn't get a chance to use in it that manner since my wife came with me on this trip, and so due to lack of space had to use it in a A frame mode which didn't do well at conserving heat, which is what i'm hoping the double wall and IR reflective liner will ultimately do.

[Ryan “Rudy” Oury]

I thought I'd posted the tarp I built a couple months back but apparently never did… so here's a couple pics and info! Biggest reason to bring it up despite the plethora of other tarps posted, is I think I'm the only person to use reinforced packing tape so far and wanted to see what people thought, why others had maybe written that tape off possibly, etc.

Basics: The tarp is a large Gossamer Gear polycro ground cloth (6'x8'). I used 3/4" wide fiber reinforced packing tape (w/ the fibers going lengthwise only) for reinforcement of the tarp, since we all know polycro is fairly fragile. As you can see, taped along each edge, and then bisecting each direction and diagonal. There are tie-outs at each corner and halfway on each edge so 8 total. I should have run the tape long and folded it pack to make the tie-outs but didn't think of that until after I put the reinforcement pieces on… so this version has small tie-outs that were just taped straight to the already installed tape ~12" back and then given a layer of the clear Duct tape over for a little addt'l adhesion. (btw, while this way wasted a little tape and was heavier, its PLENTY strong. I did a mockup on a throw away piece, put a guy line thru the tie-out, stood on the "tarp" side and ran a rod through the other side to pull on… I snapped the guy line pulling as hard as I could and the tape didn't budge.)

Weight: The weight of the tarp w/ reinforcement is only 6.4 oz. Add guy lines, stakes and my super crappy first attempt at sewing MYOG silnylon stuff sacks for total of 9oz. I'm sure if I did the taping better next time, weight could be sub 6oz and just as strong.

Testing: I've only gotten to use this one night so far, but it did just fine. Not much of a test for it though as it wasn't windy, didn't rain (until I started hiking next day) and nothing fell on it that I'm aware of.

And the pics… just did a real quick setup to see the basic shape/configuration of the taping. Could go up in any standard flat tarp pitch.
The sharpie is for reference of size… I "tared" the weight of it beforehand. 8 7/8 oz w/ tarp, guy lines (in bag) and coat-hanger stakes (in mini-bag).
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To store, I fold it until all tie-outs are at one point w/ the guy lines attached, roll it up and wrap the guy-lines around. Gets smaller than a can of pop easily.
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Worst Pitch ever, but you get the idea :)
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Close-up of edge tie-out
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Close-up of corner tie-out
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Last, quick pic on the PCT Oct '13 just West of Truckee (Lake Tahoe). Only night its been used so far.
*

[todd]

Very nice tarp, and great weight!

It appears you have a mostly taut pitch, even with the taping pattern, so I wouldn't hesitate to use this design.

Don't have input on reinforced packing tape, but it should work, IMO.

[Michael Ray]

Two main reasons against traditional strapping tape are the adhesive isn't weather resistant and the film/fibers aren't UV resistant. I'm sure you've seen boxes where that type of tape is literally falling apart on the box. :) There may be better brands out there now and most of us don't leave tarps up during the day anyway so it may work out fine for several years for you. FWIW I did some weather tests between the 3M Extreme Application Tape (8959), which is essentially bi-directional strapping tape, and the 3M 2120 transparent duct tape and the latter held up much better after 2 months exposure. It's not as strong but has worked well enough for me though I also don't get out much.

[Ryan “Rudy” Oury]

@Todd – The sad thing about that one time I did use it was putting it up took me well over 30 min… I can't even explain why, I just had NO clue what I was doing :) Practice, practice, practice

@Michael – I was guessing the UV resistance and/or water resistance was probably one of the cons of that tape but wasn't sure. Neither bother me much though since this won't be up during the day (obviously won't give much shade :))… and the tape is 98% on one side (only the folded over flaps at tie-outs are on other side) so could be pitched w/ the tape on the underside all the time thus limiting moisture exposure to condensation only. If the tarp lasts 2-3 years before the tape gives out, it would still be a success in my mind, but I'll definitely watch both of those as time goes on.

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