Cuban quilt…it’s gotta be done

Yes, I've got it now. That is why I though a dry bag style closure would be better. I could inflate the quilt and all the air will remain inside the bag even if I compress some parts. It should quickly loft back up when I move. This is something I will need to test in my dummy run!

can you explain what you mean by dry bag style closure?

Husefa,
A dry bag closure is one where the top rolls down, then either buckles together or at the sides.
Some manufacturers include SeaLine, Sea to Summit, Exped, Outdoor Research.
ULA uses this style closure on their packs. Others may also, but offhand, I don't know of any.
Here's a link showing a series of Exped bags:
http://www.tiso.com/store_images/products/RKF102_md.jpg

Chris

This doesnt make sense to me. Allison said he isnt planning to use silk inner bag, so he will have sew all sides completely. Where will be the opening?

He? I thought Allison was a woman's name. I'm not sure I get the design idea either. I was just answering your question about the dry bag closure. I'll go back to lurking and working now.

Hi, Bill-

I got the silk from Thai Silks online, 8mm Habotai. After crushing the samples in my hands several times, I'd end up with 5+ 800FP down clusters wedging their way out…

There is a way around the Cuben sweat factor if you are willing to add just a few ounces.

If you use Momentum for every other 6" of space between baffling you would have a 60% Cube 40% Momentum quilt with no condensation problems.

For you 6" spacing, lets say you have a 2" baffle.
So each section of Cuben would be the width of the quilt by 16". You would then sew the cross 6" of the Momentum in on to the increments of the Cuben.
So each piece of Cuben also forms the baffles.

The 1st piece of Momentum would be sewn 6" down then 8" down, the 3rd 14" down and the 4th with the ends of the Cuben.
When you sew Cuben edges together, it makes for a horrible seam, but with this you will always have a piece of Momentum with it, greatly increasing the tear strength of the sewn pieces.

I would also make the width of the quilt the same all the way through as the same width the foot-box is going to be.
Then you can sew additional side pieces however wide you need and just add 1/2 of the down in the areas because they will be under you anyway.

I am going to make one over the winter, as a summer bag with a footbox of 38" and the top at 42" that is about 78" long with an additional 6" side piece.

With 11 ounces of fill this will give me 2.6 ounces of Momentum and 1.6 ounces of Cuben, (.35 ounce weight).
Plus 11 ounces and you get a 14.6 ounce bag with 2.5" of single layer loft.

Aaron, your quilt idea sounds like a really nice one, but I want to make the LIGHTEST and totally WATERPROOF sleeping insulation/possible shelter/possible serape that I can. Momentum just doesn't fit with my goal, nor does having seams where the baffles join ( points of water entry and extra weight) or at the edges where extra bits might be added. It all adds weight and potential for water penetration.

I have decided to go with a 46" wide quilt-come-top bag design. The width is based on starting with 48" wide fabric while allowing for seams. The true finished width will be a little less due to lofting, so maybe 42-44 inch width? My WM POD top bag is 35" of insulation, so I'm pretty certain 42" will be ample. The quilt/top bag will have 'wings' to make it wide enough to use as a shelter, or wrap and join to my pad underneath to form a top bag.

As far as the dry-bag style closure, I envision having the foot end of the bag with a final silk baffle plus a bit of cuben overhang (this seam will be left open instead of sewing shut as you would normally do). This will allow me to roll the foot end several turns and secure the closure both at the sides and maybe one or two velcro points in the middle of the closure. I wouldn't expect to be able to use this as a flotation device, but for all intents and purposes it would be 'waterproof' and 'windproof'.

Note that I have abandoned the idea of making this a two-person quilt. That could be an add-on for the future depending on how THIS project goes. It's great to be able to brain-storm with all of you. I hope Bill F makes another appearance as he probably has the most experience working with these materials.

Hi Allison.

sorry, I didnt realise Allison was a woman's name. I even read your 'Essentials' article but I guess I didnt observe the pic carefully :)

>42-44 inch width?
Perfect. Two suggestions 1>use 2-3 shock cords instead of usual fabric loops to hold the topbag around you. This will also prevent drafts.
2> For footbox if you like sleeping on your stomach with your legs up in the air -say while reading a book or chatting, omni tabe and a knot (see jackrbetter) would be best as it comepletely eliminates any drafts.

>As far as the dry-bag style closure, I envision having the foot end of the bag with a final silk baffle plus a bit of cuben overhang (this seam will be left open instead of sewing shut as you would normally do). This will allow me to roll the foot end several turns and secure the closure both at the sides and maybe one or two velcro points in the middle of the closure.

I can see several possible problems with the idea.

1> Are you planning to use cuben for baffle walls? Cuben is NOT air permeable so if you have a opening only in the bottom baffle then rest of the baffles wont loft.

> If you plan on using silk for baffles walls then say the bottom baflle loft fully. Now some air may pass to the second baffle. Once the second baffle fully lofts -meaning it traps air- it wont allow movement of air through it. So rest of the baffles wont loft. But I may be wrong about this.

I would love to see if someone come up with a solution around this but I for now I think there is no alternative to an air permable top.

>1>use 2-3 shock cords instead of usual fabric loops to hold the topbag around you. This will also prevent drafts.

I think this idea requires more explanation.

Some people join quilt to sleeping pad using loops under the pad. My idea is to use shock cord above the pad. The advantage of this is that quilt conforms better to your body contour.

But the idea is to use shock cords while the quilt is still connected to the pad like a top bag. This will give you Montbell Super Stretch Bag like effect. :)

Its a little complicated to explain without a picture how the shock cord attaches to the top of the sleeping pad. Basically the plan is that if you are say using 2 shock cords, what you do is glue two 12"x 1" pieces of fabric on the top of your sleeping pad and feed the shock cord through it.

I have a 3/4 length underquilt. took the foot box off my nanatuk down quilt sewed the lightest wgt cuben on the bottom.So the bottom of the UQ is completely covered with cuben. it fits under my cuben hammock.(6.3 OZ)Lovely, warm and protects from wind and spindrift. and adds maybe an OZ. the UQ weighs 11.5 OZ., my over quilt has a footbox (also nanatuk), weighs 16.1 Oz, three season I suppose.

Allison, have you checked Rockywoods for cuben?

http://www.rockywoods.com/cuben_fiber.htm

This cuben is 0.253 oz/sq yd! lighter then then the cuben sold by questoutfitters.

Hi,

Buy one yard and weigh it and I believe you will find it is heavier than they say it is.

I've decided to use a dry-bag style opening, but have it roll/unroll along a side edge of the quilt. This will allow me to use cuben baffles and cuben tape throughout, yet allow quicker lofting of the down when unrolled (I Hope). The closure won't be waterproof in the submersible sense of the word, but good enough for my purposes (the closure will be backed by a silk retainer). Now I just have to do a meaure up and order some cuben and down! Hooray

Good idea. Having the opening along the side will probably solve the problems that I mentioned.

As you said previously, you would have 42"-44" width. I am not sure if you will have extra fabric to roll.

The rolled fabric will be added on to the 48" fabric. If I join it with tape then it won't compromise the waterproof design, but I'm not sure if cuben tape will stick to silk. If not, I'll have to sew that join and then tape over it. Now I'm off to make a mock-up :)

why not just use some WPB instead of silk? By attaching extra cuben, I think you are unneccessarily complicating the design.

"why not just use some WPB instead of silk? By attaching extra cuben, I think you are unneccessarily complicating the design."

Do you mean ditch the roll-up closure and just have an outer side baffle of something like Propore? I haven't found a WPB that is anywhere near as breathable as silk. I want quick lofting and packing, but your idea does have some merit. I will cogitate a bit more!

Hi Allison, any updates?

I am having a hard time picturing how you will tape the sides with the baffle walls. Only possible thing I can imagine is that you sew the long sides.

have your read Bill's 'Cuben / PrimaLoft One – Sleeping Bag' thread?
http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/5855/index.html

He says "I have rolled it tight 3 times so far. It just puffs back up."

From this I conclude that unsealed seams are very much air permeable. You may not need any silk/propore baffles. Think about it.

I have made a small sealed cuben pouch with one end made of DriDucks fabric. I put a down filled 'pillow' inside it. It was very hard to push the air out of the pillow, I can't imagine how much harder it would be to compress a whole quilt. On top of that it is very sluggish to reloft. On the strength of that I think I will stick with the dry-bag style of closure. Keep in mind that since I'm taping rather than sewing the seams, the seams are essentially airtight.

The other thing that will be really tricky is taping the fabric. I've tried both the double-sided cuben tape and the single-sided mylar tape. The mylar is more aesthetically pleasing (clear instead of white), but with both tapes you only get one chance, and if the tape folds back on itself, you have to toss it. If it accidentally touches your cuben before you are ready, you run the risk of ruining the cuben. It's scary to think about baffling many yards of the stuff this way! The fabric is too thin for me to consider sewing it (0.36oz/yd). I guess I'm getting cold feet, even though it would be the unquestionably lightest weight:warmth creation on the planet if I could pull it off.

Just thinking out loud here, have you thought about putting in an air valve like on a thermarest? that way you could compress and reloft with the twist of a thumb.

I haven't read this thread in a while so apologies if this has been discussed.

>have you thought about putting in an air valve like on a thermarest?

I would have to have a valve on the end of every baffle…not really very practical.

So the baffles are cuben too? How about takin the cuben for the baffles and perforating it, run it through the sewing machine without any thread or something so that it becomes vapor permeable?

> How about takin the cuben for the baffles and perforating it

I dunno. I think it might take a lot of perforation to make the quilt useable, and the cuben is already soooo fragile that I'm afraid to weaken it more. Think of a fabric that has the feel of a supermarket plastic bag. But I can try a test sample and see how it goes.

Hi Lynn,

I am glad to see you are still working on this.

I only sew my Cuben, no tape. I got some tape once and weighed it, it adds to much weight to the Cuben. I wasn't going to spend the money for the lightest material and then add weight to it with a lot of tape. I have never had a problem with my sewn seams. Most of the Cuben I use is the lightest sold at – 0.32 – 0.33 ounce per sq yard.

I am still playing with my all Cuben Sleeping Bag. I wish I had used a different insulation but I am not having any problems with the Primaloft One. Using the pre-quilted 1.8 ounce Primaloft One just added 1 ounce per sq yard to the weight of my insulation. If you reread my thread about the Cuben Sleeping you should read that I gave myself some extra material. This give me a bit of extra space for the insulation. It has room to loft and float a bit. I also used a wider stitch when I sewed the insulation to the inner panel of Cuben. Air can push out that seam line and suck air back in when the sleeping bag is rolled up or unrolled.