Bonded Cuben Fiber / Momentum 50 Bivy

WOW looks nice Steve.

If you ever decided to sell one what would it cost?

What do you think the total cost of materials was? This seams like a cook project. I might need one of working with cuben first but I am really jealous!

Someone help me pick my jaw off the floor. Amazing bivy Steve, you're always the guy I'm excited to see post in the MYOG thread cause I know I'm going to get a peek at something truly innovative and at the pinnacle of SUL gear making.

The question now remains, could it get any lighter? Does it need to? Why not!

Well Eugene,

He is 6'3"; I am 5'10".

I COULD make a lighter bivy then him. However I do not think that I have the patience to work with that material. Plus, my sewing machine is all funked up.

I am also in awe however. I feel like I would buy one of these. (*Hint hint*, *nudge nudge*)

I dont know how to sew, or i am too busy/lazy to do it. but I want one!

Thanks guys. Material cost isn't too bad. You need 2.6 yards of cuben fiber and 2 yards of M50. For you guys in the States (ie. low shipping cost and no duties or taxes) you could probably build this for a little over $100. If I were to sell them, I'd love to match the price of my current CR Bivy, but I'm a long way off getting this thing nailed down for production. The intricate cutting and bonding of the the bathtub floor is MUCH slower than just sewing. I have to work out some glitches.

And just for the record…it's always possible to go lighter!

Hi Steve,

You said you “always use a thin CCF pad underneath the Cuben Fiber”………. When I was designing my double skin TFD SOLO tent (where the footprint of the inner tent is no bigger than the footprint of your bivy), I also had in mind using a very thin Evazote mat under the Cuben, until I thought about substituting the Cuben Fiber with this CCF pad. Why would one want a “double” protection (CCF + Cuben Fiber) if the closed-cell foam pad won’t absorb any water? I know Cuben is very light, but still…. Can’t you glue the Cuben to the CCF? Or am I something missing here? If this would work, it would make a bivy with a CCF floor, Cuben walls + Momentum cover. Even lighter than your bivy + pad combo :)

As you said: “it's always possible to go lighter!”

Just my 2 cents.

BTW. My TFD SOLO tent is still on the design-table – therefore I don’t know if it would work out well. Another question: I originally wanted to make the inner with Nanoseeum, but if Momentum50 would be lighter I might want to go with that.

I suggested something similar to Steve some months ago and his response to me was that the CCF pads wear out too quickly to make this viable.

Henk,
First off, good thinking. This is how we end up going lighter and lighter :)

But Chris has it right. I don't think it would be wise to permanently attach the CCF to the upper portion of the bivy. I'm not saying it can't be done, just not sure how well it would hold up. The CCF rips MUCH easier than even the lightest cuben fiber. I've never tried, but I am sure sewing it would not work as the stitches would rip out, and although Momentum 90 can be bonded to some extent, the new M50 will not hold to any adhesive I tried. It literally peels off with next to no force. I'd would think you would damage the bivy rather quickly.

Of course, I have never made one so I could be wrong. I have thought about it in the past, and I've had Chris aswell as many others ask about something of this nature, so there is potential. My gut feeling is that it wouldn't work out well, but there is only one way to find out ;)

Onto the M50 vs Nanoseeum…don't they weigh the same? About 0.7 oz/yd^2? That's what I though anyway.

We all assume it weighs 0.70 but there is a big difference between 0.7 and 0.70!

I mean is it the same as 1.5 oz/yd² cuben which is really 1.43 or 1.2 oz cuben which is actually 1.26? I have a yard of noseeum from Quest Outfitters that weighs 1.01 oz/yd² according to my instruments at home. A quick error propagation shows that the most precise I can get at home with my instruments (tape measure and gram scale) is ±0.05 oz/yd² so honestly I should report the weight of my noseeum as (1.01±0.05) oz/yd². I wonder if anyone that has some nanoseeum can do the same because I don't know that I've ever seen this number questioned/.

there is a big difference between 0.7 and 0.70!

You're not one of those gram weenies are you? ;)

That's ultralight.

Hi Steve,

You’re probably right in it not being wise to permanently attach the CCF to the upper part of the bivy. Anyway, my idea was not attaching the CCF to the M50 (or Nanoseeum). I wanted to stick with the idea of having a bath tube floor and therefore I was thinking of gluing/bonding/sewing (whatever would work out better) the CCF floor to Cuben walls (of about 4 or 5 inch) and this to the Momentum (again, glued or bonded or sewn).

Since I haven't experimented yet, I don’t know which method would be better, but, as far as I can see it, if the CCF floor would tear in the field I would repair it with duct tape (maybe holding it together with a few stitches) and upon arrival at home, I’d just take the whole thing out and attach a new one to the CF walls, using the same method again. No big deal.

> “My gut feeling is that it wouldn't work out well, but there is only one way to find out ;)”
About sewing CCF: I made myself a small sit mat of some 4 mm Plastazote I had laying around and I did sew this. See picture.

As a matter of fact, this mat is multiple-use. I first made it as a part of my TFD pack (to avoid this rubbing against of my back). Since my pack doesn’t have a lid or long, narrow pockets, I need a place to hold my maps and when I decided to make my mat from 4 mm Plastazote I folded this in such a way that I can keep my maps in its interior – it even holds my TFD Wood Stove (similar design to a Nimblewill Nomad). So now we’ve got (1) padding for my back, (2) sit mat, (3) map&stove case and the last use (4) this little jewel brings to me is…… it’s part of my pillow. I used to bring a Therm-a-Rest Travel Pillow Case (34 gr), which I would stuff with spare clothing (belay jacket, pants, vest or whatever). After deciding I wouldn’t bother bringing this anymore, I tried using the Buff -I carry anyhow- as cover but I was waking up at night with just the Buff under my head – the rest would creep out through the side openings. After making the sit mat / padding / case, I found out I could use this same item for stiffening my pillow and that was enough to avoid the cloths creeping out of it. :)

And…… what’s even better: it has the same weight as the Pillow Case it substitutes – well, actually it is 1 gram LESS. The weight is 33 gr. (1.164 oz) and the dimensions: 32 x 24 cms (approx. 12.6" x 9.45”). Perfect for the padding of my back and stiffening of my pillow, more than ample for my map&stove case and, although it could have been a wee bit larger for my but, it does keep this warm even when sitting in the snow :).

Great post Henk! You've given me a lot of new ideas to think about.

"We all assume it weighs 0.70 but there is a big difference between 0.7 and 0.70!

I mean is it the same as 1.5 oz/yd² cuben which is really 1.43 or 1.2 oz cuben which is actually 1.26? I have a yard of noseeum from Quest Outfitters that weighs 1.01 oz/yd² according to my instruments at home. A quick error propagation shows that the most precise I can get at home with my instruments (tape measure and gram scale) is ±0.05 oz/yd² so honestly I should report the weight of my noseeum as (1.01±0.05) oz/yd². I wonder if anyone that has some nanoseeum can do the same because I don't know that I've ever seen this number questioned/."

There are small variations in specs between lots, on the order of 5%, but here are some current weights to the hundreds of an ounce spot rather than the 0.7 oz/yd2 listed on my site.

2 yd by 50.5" piece nanoseeum: 0.71 oz/yd2. (this is from the current 48" wide roll)

2 yd by 64" piece nanoseeum (different lot) came in at .73 oz/yd2. (this is from the current 60" wide roll)

Scale used: myweigh mx-200

Independent verification welcomed.

Paul is the man! Good to know that nanoseeum is (0.72±0.01) g/yd².

Paul,

That's consistent with the results I saw from the 55" wide stuff you had. Tested on two digitals, accurate to 1/10th gram. Came in right at .73