Cuben Tent Fly

[Dan @ Durston Gear]

I'm nearly finished my homemade tent fly made from bonded 0.7oz olive green cuben. Here's how it went down:

First I cut this large piece of cuben and draped it over the tent. The first objective was to get it attached to the ends of the poles above the doors using a grommet.

I used a hot knife (thanks Lawson!) to cut the cuben which worked great. I cut 4 reinforcement patches for the two grommet areas so it would be triple thickness.

Next I cut a slit in the reinforced patches and overlapped it a bit to give it a 3D cone shape to improve the fit and glued it. Then I tapped the grommets in place.

I was relieved that my measurement between the two grommet points was accurate and I got a nice tight line of tension across the top of the fly.

Next I pulled the cuben tight and used a dry erase marker to draw the edges along the pole lines. Using a similar technique, I cut out a piece of cuben for each end of the tent. Then I bonded this into place with Hysol.

Now I cut out the last two main panels for the other half of each door and the corner of the fly.

Next I finished the edges of the fly by folding it over about 1" and gluing it.

Then I did the corners. I cut a 7" x 2.5" cuben piece and folded it down to 7" x 0.5" to fit the line loc 3's. I glued this on the fly and then added reinforcement patches over it on the both sides of the fly.

Here's the fly attached at the corners:

Next I did basically the same thing at the doors.

Then I added some reinforcement patches at the top of the zipper area and sewed both zippers into place

I added a grommet at each end of the tent for the fly stake out which is necessary to keep it off the inner tent. The original fly is like this too.

Here's a few more pictures of it nearly done. All I have left to do is add a guyout spot at each corner of the tent, add a way to hold the doors open and cap the grommets above the doors so rain can't leak in.

My sewing machine is terrible. Its pure plastic and it was $25 new at Michaels craft store. It had some troubles picking up the loop on the underside but eventually I got it sewed. The sewing isn't pretty but it seems strong.

The weight of my original fly was 23.0oz and this new cuben fly is 10.0oz as it currently stands. It will likely finish at about 10.5oz, for a weight savings of 12.5oz. The 10oz fly weight includes 7oz of cuben, 2oz of zippers/sliders, 0.4oz for 8 LineLoc3's and the other 0.6oz is the grommets and cordage.

EDIT: The 7oz attributed to the cuben also includes the weight of the Hysol adhesive. Since I used an entire tube of Hysol for this project. I'd estimate about 1oz is the glue.

[Jeff Antig]

Minimal sewing–my kind of DIY!

[David Ure]

Dan – nice job!!

[Jeffs Eleven]

I've been wanting to see your results- pretty cool stuff, man

[Kyle Crawford]

Nice work. And for 1/4th of the weight, I'm sure.

[Colin Matthews]

Great job Dan, that looks very clean!
Will be interested to hear how the cuben stands up to condensation issues, especially in the pacific northwest. hit us up with a report once you've used it a few times!

[Lawson Kline]

You did a really awesome job. Don't be surprised if REI offers you a job re-engineering some of their tents.

[BlackHatGuy]

Very nice Dan! When will you be setting up shop? ;-)

[>> Bender <<]

Dan what do the poles & inner tent weigh? Was the original fly constructed in more pieces than the Cuben one?

[t.darrah]

Dan,
Why the tie out grommet and not a reinforced line loc as used in other locations on the fly?

[Brandon Sanchez]

No vents? Could be a clammy situation….

[Steven Evans]

Awesome work my friend. Looking foreward to a trip report.

[Dan @ Durston Gear]

Q) Minimal sewing–my kind of DIY!
A) I bet you could do it with zero sewing because the waterproof Uretek zippers seem to bond really well to the cuben with Hysol. I thought about doing this but I didn't want to take the risk of a zipper failure in the field as that would be quite problematic.

Q) When will you be setting up shop? ;-)
A) This thing took a ton of time to build. I was really careful with all the measuring etc so I probably put about 30 hours so far into it. I had virtually no experience with any of the skills needed for this project, so anyone with some patience could accomplish something similar.

Q) what do the poles & inner tent weigh?
A) The original poles are 450g (15.9oz) and the inner is 594g (21oz). I've ordered some Fibraplex poles for this tent which should weigh half of the stock poles. Cuben Fly + Carbon Poles + Inner should be approx. 39oz or 2lbs 7oz. Under 2.5lbs for a double wall, 2 person, dual door, dual vestibule, decently spacious, freestanding shelter was my goal.

Q) Was the original fly constructed in more pieces than the Cuben one?
A) Yes, my large initial panel that angles across the top of the tent was 4 pieces in the original fly. The end panels are the same and the last corner/door panel was 2 pieces. So my fly is 5 pieces instead of 10.

Q) Why the tie out grommet and not a reinforced line loc as used in other locations on the fly?
A) I didn't think it was necessary. The grommet is lighter than a LineLoc3 and there is very little load on this grommet. I just need it to prevent the fly from touching the inner under wind deflection. I use 2g Terra Nova stakes for everything with this tent except for the vestibules where I use 8g Ti stakes. The grommet is 1.3g and a LineLoc3 plus reinforcement patches and a folded cuben strap is ~4g.

Q) No vents? Could be a clammy situation….
A) The original fly did have two vents. I might add these but honestly I've never noticed a big difference when using the original fly with them opened or closed. Last summer I had a MSR Carbon Reflex 2 which is a very similar shape with no vents and I had no excessive condensation issues.

[Brian Martin]

How much Cuben did you order and how much did you end up using. What was the standard width on the roll? I've been tossing around doing this same thing for my CS UL2.

Thanks.

[Hught]

Awesome! Am learning the vagaries of Cuben on my own little project. One issue you mention in your project caught my eye –
"My sewing machine is terrible. Its pure plastic and it was $25 new at Michaels craft store. It had some troubles picking up the loop on the underside but eventually I got it sewed."
I had this problem too when sewing cuben – switching to Microtex needles (specifically for thin materials) solved it for me – may be worth a try if you are doing more cuben sewing.

[Dan @ Durston Gear]

Cuben is sold by the meter (39") rather than the yard (36"). I ordered 18 meters to be safe for this project. I sold 5 meters right away and finished with 4.5 meters left, so this fly required 8.5 meters of material. That works out well because Cubic Tech only sells cuben in 9 meter increments. As you can see in the pictures, I wasn't super careful with not wasting any cuben because I figured I could always use the scraps for stuff sacks etc. I probably could have done this fly with 7.5 – 8 meters if was more careful.

The roll is ~53" wide of usable cuben. There is another inch or two of mylar on the sides without any fibres in it so you don't want to use that. You can sorta see this clear bit at the edges of the fabric in the first picture in this thread.

For the sewing, I ended up just sewing it one stitch at a time. I would tap the pedal to sew one stitch and if it didn't catch then I would move the fabric back and re-try that stitch. It was slow going (about 4 hours total sewing time for 2 zippers) but that worked okay since I rarely sew. I'd want to resolve this problem if I was doing much more sewing.

[>> Bender <<]

I'm remaking a fly out of sil-nylon and I can get away using 8.2 linear yards. Then tent is very similar in design and size. If in doubt get out the measuring tape!

[David Olsen]

A needle not picking up the bobbin thread is usually a
timing issue. The needle is not in the proper position
to the bobbin hook when it comes around. Also the thread
can stick to the needle and prevent the hook from picking it up on some materials.

1. try lowering the needle a millimeter. If this helps,
then you can have the machine re-timed to work properly.
The wrong length of needle can also be a problem. You
may need a longer one.

2. if the thread seems to be sticking, try putting a little
sewing machine oil or silicone lubricant on the spool of
thread so the thread is pre-oiled.

[Dan @ Durston Gear]

I think a big part of the problem was that I was sewing when the adhesive wasn't 100% dry. I sewed the first zip only a few hours after gluing it and it was a major pain. The second zip I sewed the next day and it worked a lot better. There was still the occasional miss (ie. 5% of stitches) but it was nowhere near the 50% or so miss rate of the previous day.

[Jason Hung]

Very nice work!!
i like to know what kind of glue do you use to glue the edge of the folded tape?

[Brad Groves]

Nice!

[Unknown abc]

very impressive! :)

[. .]

Thanks for sharing, Dan; and very nice work. Yours is the first double-wall Cuben set-up I've heard of. The color goes well with the tent as well. You have well demonstrated what the potential is, that few (if any) have tapped into yet, for LW luxury backcountry shelters.

[Dan @ Durston Gear]

Q) What kind of glue do you use to glue the edge of the folded tape?
A) Everything has been glued with Hysol U-09FL

"The color goes well with the tent"
The crazy thing is that this was the only color Cubic Tech had available at the time and it's pretty much exactly the color of the original fly.

I added four guyout points to the fly yesterday:

It's hard to see in the pictures what I've done so I'll explain it. I started with a 6" x 2" rectangle of cuben and folded & glued that 4 times to create a strong 6" x 0.5" strip of cuben. Then I folded it and sewed it to create a loop in the middle. I then glued a 0.5" section of a clear Bic pen tube into this loop to spread out the force when a guyline is attached.

Next I cut a slit in the fly and inserted the two ends of the cuben strip. I splayed them out and glued them to the inside of the fly so that the forces are in sheer instead of peel. Then I glued a large circular patch to the inside of the fly to reinforce this area and ensure that it's all watertight. Then I added a smaller circular patch to the outside of the fly to ensure that the slit I cut in the fly doesn't grow any larger. Hopefully that makes sense.

The weight added was 1.0g per guyout or 0.15oz for all 4.

All that's left now is figuring out a way to hold the doors open and I need to cap the grommets above the doors so it's watertight.

[Tim Marshall]

is there a way to slide an o-ring on the poles so when they mate with the grommet they seal themselves?

-Tim

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