Walmart Pad Questions?

[HappyHiker]

I wonder why a pad causes a condensation problem in a hammock when it doesn't when used on the ground.

I think it's because you have a lot more contact area using it in a hammock- it wraps the back, shoulders/arms and legs. On the ground it touches only contact points on the back, arms and legs.

Also, less movement while sleeping. I either find myself in the same position I fell asleep in, or at most wake once or twice to shift positions. When sleeping on the ground I move around quite a bit more allowing any condensation to dry that may have accumulated.

[mrmike65]

@ HappyHiker: sounds logical. Thanks for the input.

I wonder if the fact that most hammock setups are near-enclosed environments doesn't have something to do with it as well. I've never used a bivy sack. Does anyone here have experience with sleeping on a pad in a bivy sack that they could speak on the issue of condensation in that environment?

[HappyHiker]

I wonder if the fact that most hammock setups are near-enclosed environments doesn't have something to do with it as well. I've never used a bivy sack. Does anyone here have experience with sleeping on a pad in a bivy sack that they could speak on the issue of condensation in that environment?

Personally I find hammocks to be very open enviornments - lots of air movement through the tarp area (dependent on doors, materials, height of sidewalls from the ground etc.). Most of the condensation I see in a hammock is on the pad, bag/quilt where I breathed on it all night and occasionally on the tarp (but Colorado is generally a very dry area). The worst being on the pad, where it's trapped and has little/no air circulation.

As for a bivy, IME they do increase condensation everywhere (especially when closed due to weather). Far worse than a hammock. Of course my bivy is a 15+ year old gore tex model. There are quite a few fabrics that are newer and more breathable that are able to reduce condensation in theory - but I haven't tried them.

[mrmike65]

Thanks for your response. Perhaps, I'm seeing a more closed environment because I may be setting my hammock too close to my tarp. That the difference in condensation between using a pad on the ground vs. in a hammock is that the pad in a hammock has more contact with your body doesn't seem to add up. The bottom of a hammock is subject to more airflow, is it not?

Ahh... the missing factor could be because the bottom of the hammock is exposed to cooler air and there is a heat bank just on the other side of the pad. Condensation being the result of cooler air meeting warmer air.

I wonder if there is a way to "break" the cool air/warm air condensation cycle by using thin layers of insulation alternated with layers of non-conductive or reflective layers. Say... three layers of Insultex, alternated with two layers of Mylar, in a shell of 1.1oz RSN. I would guess that a 3/4 pad would be < 1/2" thick and weigh about 8oz. Fashioned correctly, a pad 30" by 48" could be worn as a vest.

[Randy]

There is absolutely nothing wrong with those Walmart ccf pads. The green GI pads are a little wider and about $15.00 more.

[mrmike65]

Do you find there is no issue with condesation with your pad?

[Randy]

I get some condensation sometimes.. but the cost of a pad versus an underquilt,I am just fine with using a ccf pad.
I am sure that the underquilts are great, but so is a rolex........

[HappyHiker]

Thanks for your response. Perhaps, I'm seeing a more closed environment because I may be setting my hammock too close to my tarp. That the difference in condensation between using a pad on the ground vs. in a hammock is that the pad in a hammock has more contact with your body doesn't seem to add up. The bottom of a hammock is subject to more airflow, is it not?

Ahh... the missing factor could be because the bottom of the hammock is exposed to cooler air and there is a heat bank just on the other side of the pad. Condensation being the result of cooler air meeting warmer air.

I wonder if there is a way to "break" the cool air/warm air condensation cycle by using thin layers of insulation alternated with layers of non-conductive or reflective layers. Say... three layers of Insultex, alternated with two layers of Mylar, in a shell of 1.1oz RSN. I would guess that a 3/4 pad would be < 1/2" thick and weigh about 8oz. Fashioned correctly, a pad 30" by 48" could be worn as a vest.

Even with the tarp riding my RL, theres still much better airflow than in a tent (unless the tarp is so tight against the hammock it's creating an OC (over cover).

Condensation can occur from several different sources - either from moisture in the atmosphere (cold glass of liquid on a hot day for example), or from you (warm hand on a cold window or mirror). In the situation of a pad, it's the latter. The pad is a VB which will not allow water through - the moisture is being generated by you and with no avenue to escape, it collects. The temp differential has some effect, but it's not the predominant factor. Wear a trashbag as a shirt on a warm day - guaranteed you'll generate moisture even with a lack of temp differential. That's one reason UQ's are so highly regarded - they breathe well.

Insultex and space blankets are VB's as well. You may move the collection point further from you, but it will still collect.

HTH

[hangNyak]

I cut my WW pad to 3/4 length and made an SPE. The cut off portion of the pad I used to make the "wings" for shoulder and hip areas. It works well. I have had no moisture issues, but I have only had it to 60*. Here is a pic.

[mrmike65]

Thanks for the clarifcation, HappyHiker, and for sharing your pic, hangNyak. I have plenty to think about now. Much appreciated!