Cuben Lined UQ

**SamuelJD** · 09-30-2011, 19:27

I have thought about using cuben fiber as the liner in the construction of 3 UQ's I am making. I got this idea from Grizz's DIY underquilt ( http://www.hammockforums.net/forum/s...ead.php?t=6466 ). He uses sil nylon as a vapor barrier. I think sil nylon and cuben fiber would have the same effect. Now correct me if wrong if the liner is not breathable what would be the positive and negative effects. I plan to conduct more research on heat conduction but I for now have some common sense questions. If the liner is not breathable vapor and moisture from my body will not penetrate the material. Thus conducting thermal energy to the down. The cooler more dense moisture will obviously condense under myself or in my clothing. Well I reckon I could turn on my side when I am getting a little sweaty. Heat spontaneously flows from areas of higher temperature to areas of lower temperature coming to an equilibrium. Heat conduction moves through mass or matter where in convection transfers in bulk motion of matter. The thought I have is what happens when cool air and hot air interact and form moisture in between the shell and liner. Well Heat rises and cool air falls. The cool moist air would be advected by the cool air's current of movement flow through the breathable shell. The warm hot air rises and would conduct heat energy through the liner. hELP ME OUT ON THIS EVERYONE.

**GrizzlyAdams** · 09-30-2011, 21:00

Originally Posted by SamuelJD

I have thought about using cuben fiber as the liner in the construction of 3 UQ's I am making. I got this idea from Grizz's DIY underquilt ( http://www.hammockforums.net/forum/s...ead.php?t=6466 ). He uses sil nylon as a vapor barrier. I think sil nylon and cuben fiber would have the same effect. Now correct me if wrong if the liner is not breathable what would be the positive and negative effects. I plan to conduct more research on heat conduction but I for now have some common sense questions. If the liner is not breathable vapor and moisture from my body will not penetrate the material. Thus conducting thermal energy to the down. The cooler more dense moisture will obviously condense under myself or in my clothing. Well I reckon I could turn on my side when I am getting a little sweaty. Heat spontaneously flows from areas of higher temperature to areas of lower temperature coming to an equilibrium. Heat conduction moves through mass or matter where in convection transfers in bulk motion of matter. The thought I have is what happens when cool air and hot air interact and form moisture in between the shell and liner. Well Heat rises and cool air falls. The cool moist air would be advected by the cool air's current of movement flow through the breathable shell. The warm hot air rises and would conduct heat energy through the liner. hELP ME OUT ON THIS EVERYONE.

you definitely get warmer, thinking about this stuff so hard. It's a gram-weenie trick, you can carry less bulky quilts that way

My underquilt the last couple of years has been a DIY 3-season job with Cuben inner body. I haven't experience condensation, but suspect this varies from person to person.

I recently made a thicker UQ made almost entirely of Cuben, but have yet to test it in cool temps. Perhaps this weekend....

**Oms** · 10-10-2011, 21:32

I would think cuben a much better choice for colder weather. Would it be much different then laying on a pad? Possibly a little more breathable then a pad due to air infiltration, but then I hated having a sweaty back using a pad. As for the cuben UQ, I think it would stay drier from lack of body moisture. Good question. I've been kicking it around as well.

**traftonm** · 10-11-2011, 08:10

I did my under quilt with 1/2 cuben and 1/2 momentum 50. Each chamber is cuben on one side momentum on the other. With 12oz of down it came in at 19oz. So far I have only had ti to 35*, dut I was very comfortable.

**Oms** · 10-13-2011, 20:27

Anybody with a sweaty back?

**JohnCR** · 10-15-2011, 01:10

I would of thought that trapping vaper ie sweat creating sweaty patches would be dangerous in cold climates? surely damp kit would weigh more also create problems if it freezes! Try using breatheble down filled underblankets as they are lighter than synthetic, if your tarp is any good I doubt it will get wet.

**traftonm** · 10-15-2011, 07:30

Originally Posted by Oms

Anybody with a sweaty back?

The way I made the UQ it is breathable, and I have had no problem with sweating. If you used all Cuben on one side you would have problems with sweating.

**Towellie** · 10-15-2011, 08:10

From what I understand, you only want vapor barriers in very cold conditions. There is a fine line for when a vapor barrier helps and when a vapor barrier has negative effects. For a more detailed analysis on how/why vapor barriers work and when to use them, refer to this thread.

**Dos** · 10-17-2011, 11:14

traftonm-
beautiful UQ! wow.

you are srsly enrolling me in the DYI sector

**Oms** · 10-18-2011, 05:36

Of all the down products I have bought, I have gone with the philosophy that a breathable fabric is better. Your body will pass moisture and if there is a way to prevent build up or allowing it to pass through, then it will help insure the R value. Then along comes cuben. Super light, no leakage of down, but also water proof. It would help keep the underquilt dry, but there may also be a build up of moisture around your body that will be directed up to the top quilt. Possible I'm reading more into this then I should. Think I'll try a vapor barrier between my hammock and UQ before I take the plunge and buy an UQ with cuben. How about some of the other lightweight fabrics, do they leak down?