Cuben Fiber Tarp Construction

[hangnout]

Cat cuts - not necessary but look good. I keep the arc about 1/2 of what I do on sil.

Best tip of the day

Draw your cat arc on the cuben, run your tape along the line BEFORE making any cuts, take a razor knife and trim along edge of tape, fold over and apply.

This makes for a perfect easy cat cut that utilizes 100% of adhesive. This is actually easier than a sil tarp.

[MattK]

Hangout, thanks for being a wealth of information for me to plunder!

Do you think a cat cut is worth it on the RL, or should I just keep that straight? Planning on the sides having a 2" cut and the doors having a 1" cut.

[hangnout]

Hangout, thanks for being a wealth of information for me to plunder!

Do you think a cat cut is worth it on the RL, or should I just keep that straight? Planning on the sides having a 2" cut and the doors having a 1" cut.

I would do a straight RL. The only reason for a cat cut RL would be to keep the tarp tight. This is not needed with the cuben. The temptation with cuben is to treat it like a silnylon tarp in design and tarp tension. The cat cuts concentrate the tarp tension to the tieouts. Cuben is not stretchy but it will stretch and never return to orginal form. The polyester membrane that sandwiches the dyneema fibers will stretch especially in the heat. Around 90 degrees and up it can be a real problem. I actually put the JRB style tarp tensioners on my cuben tarps when I loan them out. The tarp tensioners ensure that the tarp is not over tensioned. I don't use them but I have learned the hard way to not over tighten cuben. I have not used cat cuts on the last few projects and have added a third tieout in the middle on the front edge of tarp for extremely windy conditions.

Cat cuts along the sides are more cosmetic than necessary but I would not use one on the RL where it is always under a tight tension. I use a continuous RL under my cuben tarp. This setup does not put a lot of stress on the cuben RL tie out areas.

HNO

[MattK]

Hangnout, I owe you for all the help!

Thanks for the insight on the RL. I will go with a straight cut. Seems like the benefits would be minimal.

Also, I appreciate the info on over-tensioning the cuben. My thought right now is to put small shock cord loops on the all the tie outs to start, so hopefully that will avoid any issues. Where I camp it is rarely so warm, but I would rather not toe that line at all. Also, I plan to try a single-line/all-in-one suspension where I can just clip the tarp to the hammock suspension, so a little give and take will be nice.

I will let you know how things go once I get started!

[gringoperdido]

1/2" for the ridgeline is strong enough....I used Ti 'D' rings attached with strips of cuben(reinforced both sides)for the tieouts(no sew)... panel pulls were the same.
All still holding up surprisingly well after a couple of years of use.

Sounds like an elegant solution - simple and strong. Do you have any pics?

[ofuros]

Sounds like an elegant solution - simple and strong. Do you have any pics?

Newer tarp glimpses in my signature below....

Page 3 on this thread contains the tie out info I used...origami tapered patches over the 'D' ring strips.
Wouldn't change the process for the next tarp either. Strong & simple...
https://backpackinglight.com/forums/...ge/3/#comments

Older pics...
https://www.hammockforums.net/forum/showthread.php/85939-DIY-Cuben-Tarp-all-tape-no-stitching

[MattK]

Very innovative reinforcements ofuros! I may have to experiment with something like that for my next round. If I can ever afford to buy more cuben fiber...

I figured I would give a quick update:

I decided to use 1" cat cuts on the doors, 2" on the sides, and a 2" cut on the RL. After hunting around on BPL for a bit, and looking at some of the highly rated production tarps, there was a lot of good things to be found about doing a cat cut on the RL. I had to cut there anyways, to remove the salvage from the edge of the cuben.

I used 1" tape for the RL, per the recommendation of the folks at Make Your Gear, RBTR, and Zpacks.

I found this video to have some helpful tips: https://www.youtube.com/watch?v=SO2YxhzZlpc

I cut circles of 1.43osy cuben for the reinforcements. Larger ones for the "top" and a smaller patch, just to catch the stitches of the tie outs, on the "bottom".

20161101_123250.jpg20161101_123235.jpg

I plan to make a rolled hem (with stitches) and then bar tack the 0.5" grosgrain tie outs on.

Thanks for all the help!

[MattK]

Completed the tarp! Turned out really well. Here are a couple quick notes, for anyone else who may be interested in a similar project:

1. I over-built the tie outs. Using the 1.43osy w/adhesive on one side of the tarp would have been plenty strong. I would skip the secondary reinforcement on the underside. I would switch the RL tie-out reinforcements to be 1.43osy, instead of the cuben hybrid material. I think I would keep the secondary reinforcements on the RL.

2. Reinforcement placement was off. I didn't account for the ~1" of fabric for my rolled hem, so the reinforcements don't look to be truly radial. Next time I would set the center of my circles into the tarp body 1" so that after the hem is done, they would be the full radius of the circle.

3. I like the Cat cuts. I did a 2" catenary curve on the RL and sides, and 1" curves on the doors. This tarp pitches very taut, very easily. This is in comparison to my cuben square tarp, which is truly flat. The only downside is I should have taken more time while rolling the hems. The longer edges didn't come out all that clean. The RL and doors turned out great though.

And a couple pictures, hanging over my Hexon 1.0 bed:

20161111_153746.jpg

20161111_153812.jpg

I have one side up in porch mode, the other side down to block wind. Great space, great protection, and very light at 265g (9.3oz) including all tie-outs, RLs, panel pulls, and a 1-peice nano-seeum mesh snakeskin.

Thanks for all the help!

[Double]

What Cordage are you using for your tarp. Is it 1.25 mm Z Line or something else?

[ofuros]

Looks good....