Poor Man's Cuben: Polycro Tarp
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Dan Johnson
(Seattle)

Locale: PNW
Poor Man's Cuben: Polycro Tarp on 01/31/2012 14:07:47 MST Print View

So it's been in the works now for quite a long time now but I rarely have free time anymore now that I have a daughter (9 months old). Today I finally was able to do a quick pitch in my house using various pieces of furniture as stakes as she was taking her normal morning nap. This is my first attempt on making my own tarp and I learned quite a bit after I pitched it. Thanks to everyone here that helped me along in the process. I used a patio sized window shrink wrap kit which measures roughly 7x9. I also put the double sided tape that was included in the kit along the perimeter and folded over the plastic to create a stronger edge. I found this really helped in strength and I'm not too worried about the edge getting a tear in it anymore. I don't have a scale to weigh it but compared to my cheap blue 8x10 poly tarp this feels like nothing. All folded up it fits nicely in a gallon sized ziplock bag.

Without further ado:

Tarp

Tie outs

perimeter fold

Things I would differently next time. Instead of 4 tieouts on the long side I would just put 3. I would use less tape. And I would sandwich a plastic washer between the tape on the tieouts.

Now all I have to do is get a long enough rope for the ridge line and I'm set to try it out on the trail.

Edited by Seattle on 01/31/2012 14:43:41 MST.

Daryl Daryl
(lyrad1) - MLife

Locale: Pacific Northwest, USA, Earth
Re: Poor Man's Cuben: Polycro Tarp on 01/31/2012 14:42:33 MST Print View

Thanks for the photos and info.

I like the imbedded plastic washer idea.

What type of tape did you use for the corner reinforcements?

Dan Johnson
(Seattle)

Locale: PNW
Tape on 01/31/2012 14:47:26 MST Print View

I used Gorilla Tape. I tried today to peel off the middle two long sided tieouts and make one centered one but I couldn't get the tape off! I guess I'll just have extra tieouts. The tieouts do feel really strong, but that could also be from how much tape I used.

Ultra Magnus
(Ultra_Magnus) - F
Re: Poor Man's Cuben: Polycro Tarp on 01/31/2012 14:51:34 MST Print View

It will be interesting to hear back how it ended up working in practice. I would also like to hear back if there were any issues with it snagging on pokey branches/weeds/brush etc...esp. when pitching it in the wind.

>"but I rarely have free time anymore now that I have a daughter (9 months old)"
I hear you... I also have a 9mo daughter (my goodness is she an absolute angel), and a 2yr old boy, another 4yr old boy, a 7yr old daughter, oh- and two more boys, 9 and 11... :D Yeah, I gave up any notion of having time to myself a long while ago. When I want to work on a project, it's usually done a few minutes at a time in between fights, feedings, diapers, or after they are in bed. Sleep is for the weak!! j/k...

BM

Dan Johnson
(Seattle)

Locale: PNW
Packing it up on 01/31/2012 15:04:33 MST Print View

I'm kinda worried about packing it up in camp. Hopefully there isn't any sharp twigs or anything that will poke the material when I need to fold it up. I still haven't found a good way of folding it up for packing it away. It seems to take a while since I want to be careful of the material. If it was 2 or 3mil plastic I wouldn't care as much.

Brian UL
(MAYNARD76)

Locale: New England
Re: Poor Man's Cuben: Polycro Tarp on 01/31/2012 15:08:40 MST Print View

Please let us know how it works on the trail.
I had the same idea a long time ago. I never followed up on it like you did. The ground sheets from GG seemed so strong for their weight I thought - why not throw a tarp together made of this stuff instead of the crazy expensive materials I have been using?

Dan Johnson
(Seattle)

Locale: PNW
Life span on 01/31/2012 15:21:23 MST Print View

Since I can only get free to do an overnighter about 2 times a year it doesn't make sense for me to buy anything more expensive. I figured it lasts me a year (just a couple trips) then I'll be happy. I will just have to pick my campsites carefully where I'll have a good wind block and I think I should be fine. I am amazed at how easy this was to put together though. If I had a free hour I could make another one now that I know how I want the end product to look like. Total cost was about $12 for the patio kit and the roll of gorilla tape. Hard to beat the price :)

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: Life span on 01/31/2012 15:25:33 MST Print View

Since weather is unpredictable, what are you going to do when/if the weather destroys your shelter? I have made tarps out of plastic, but would never risk/rely on polycro. Perhaps you might want to consider if this tarp is "penny-wise and pound foolish."

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Life span on 01/31/2012 15:35:18 MST Print View

I've carried thin plastic tarps like this, but only for a pure emergency. They work OK for vertical rain and if you are deep in the trees to protect from wind.

--B.G.--

Corey Miller
(coreyfmiller) - F

Locale: Eastern Canada
Weight on 02/07/2012 16:53:44 MST Print View

Could anyone estimate the weight on this? I may get some of this to use to extend my hammock tarp.

Dan Johnson
(Seattle)

Locale: PNW
Weight on 02/07/2012 21:47:10 MST Print View

I wish I could tell you the weight but I don't have a scale. Hopefully this weekend I'll be able to test it out in some rain. I had it setup outside in my yard for a couple hours with no wind break around and it faired pretty well (there was very little wind) but I would NOT want to rely on it when wind is present. So I will definitely be setting this up deep in the trees. I'll report back this weekend!

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Poor Man's Cuben: Polycro Tarp on 02/08/2012 08:53:34 MST Print View

Interesting idea to use the included tape and just fold over the edge. As I mentioned before I have not tested polycro for stretch and tear resistance yet so that may work OK for you. I'd pull pretty hard on one of those side tieouts and see how the material deforms. If it does, add some tape along the edge to distribute the force better.

You certainly went overkill on the tieout tape though. The washer may be a good idea also though I've had no trouble with my tieouts made of just 7/16" tape and I know I've had 35 mph gusts.

I would just add tieouts for your ridgeline also rather than run a longer line but the polycro will take a decent amount of force so I'd be inclined to tape the ridgeline (not with full size GG though!)

Frankly, I'd keep the extra tieouts on the side. I would have added one more even. If you get in a stiff wind, you'll want it I bet. The more tieouts to keep the panel taut the better.

When I make mine, I'm not going to be too concerned about snags, etc. This stuff lasts for months as a groundsheet. You also don't need to be careful folding it up. Do it just like your groundsheet. Fold it over a few times on the short edge then roll it.

Weight of polycro should be on the order of 4.4 oz (125 g). At least my 7x10 piece (Duck brand) weighs that. Tape adds quite a bit, especially the GG he used.

Leave it pitched in your back yard during storms so you can see how it does. That is what I did with my LDPE one. It stayed pitched for 2 weeks and survived several thunderstorms just fine. It was my dog who got tangled in my guylines that damaged it. The beauty was I could just tape up all the tears and have used it for my 2 Rockies trips.

I personally would go with the half pyramid pitch vs A-frame in a storm though. However, this is so big maybe that won't matter. Mine is just a 6x8 (2 Heatsheets taped together), and I don't use a bivy.

Jack Hoster
(OrlandoHanger) - F
Poor Man's Cuben: Polycro Tarp on 02/12/2012 15:54:18 MST Print View

I see that D Johnson is from Seattle. Isn't that were it rains all year, expect when an inch of show shuts down everything and makes travel impossible. Sounds like an unpleasant place to experiment with this.

I'd love to see how this works out and hope you make it back alive.