I've been waiting to test this out for a while now. 3 nights, temps in the upper 30's and lower 40's. I slipped a mylar space blanket in between my Phoenix 3/4 summer weight down quilt and my hammock. No condensation and I noticed a significant warmth difference when I would shift my sleeping position and not shift the mylar.
Last edited by CrankyOldGuy; 10-15-2012 at 10:57.
"A bore is a man who deprives you of solitude without providing you with company." Gian Vincenzo Gravina (1664 - 1718)
Had a friend out with some Cub Scouts (his son's troop) and he was the only father hanging. Had an triple layer IX UQ he needed to supplement with a few things since nights here were getting to below 30 degrees. With a few add-ons - he used a thin pad, lowered the tarp etc he was toasty warm.
The key to immortality is first living a life worth remembering. - St. Augustine
Some people feel the rain. Others just get wet.
- Bob Marley
At this point someone is supposed to post about warmth being subjective, aren't they?
"A bore is a man who deprives you of solitude without providing you with company." Gian Vincenzo Gravina (1664 - 1718)
I made my own underquilt out of an old sleeping bag. It's a really cheap bag. I don't expect to keep me warm much under 40*. I was testing it out in the backyard and threw a space blanket between my hammock and my quilt. It was amazing the heat I insatantly felt radiating back at me. I am concerned about waking up clammy after a nights sleep. I'm gonna give it a test run tomorrow night. The lows will be around or below freezing. I am consider the combination of my thermarest and my UQ.
"Education is the ability to listen to almost anything without losing your temper or your self-confidence."-Robert Frost
That has been working for me for six years in the HHSS and the Pea Pod. Now I see that it also works with the Phoenix, and on the theory basis I can't see any reason why it would not. Very interesting that you had no condensation ( as theory would predict ) on a warm side SB just as I have never have using an SB in either my pod or HHSS. But some folks do get some in their HHSS, which though I believe them, continues to baffle me.Originally Posted by CrankyOldGuy
I'd say your results are not subjective at all, as you are comparing you to yourself when you get off of the SB and it feels significantly colder. Sounds like pretty straight forward results, A/B comparison to me. Remove the SB, it feels colder.At this point someone is supposed to post about warmth being subjective, aren't they?
What I always ponder is: is it the reflective barrier of the SB + it's VB qualities, or is it all just rally VB? After all, there have been folks who claimed 15 to 20* warmer using just VBs, and I don't think that even counts the deterioration or insulation which is gaining weight from condensing vapor on a longer, cold trip. I have always guessed that the SB added to my HHSS adds about 15-20 additional warmth, not much dif than what would be expected with a plain VB. But that is just my rough estimate, I guess it could add even more.
Wonder how low you can take that UQ adding the SB/VB?
Some time when you have really pushed the UQ ( by itself) to it's limit for several nights, weigh it. Then on another experiment adding the SB, weigh it again. If their is an oz or two more weight, that is water that is in your quilt, obviously. This is more likely to show up ( I suppose ) at temps colder than you might use that 3 season quilt, but it might even show up in the 30s or 40s. Some one here, at a deep winter below zero hang, did such an experiment, but can't remember who it was at the moment. But I thought the differences were significant, even more so since he attempted to dry the non VB quilt in the cold sun, but not the VB quilt. I think there was several oz less weight in the VB test, even though no attempt was made to dry it and even though it was a short trip.
I'd say your biggest risk is over heating and actually sweating. Then, if you are inside a sleeping bag or wearing a parka, the insulation will soak up the sweat. So, try not to over heat your back!Or if you do, don't have much insulation between you and the sp.blanket. That is one reason why I am a fan of VB clothing, which is the closest thing to my skin except maybe for the thinnest possible long john layer. If I do sweat, none of it will get into my main insulation.
Let us know how it goes! Weigh your quilt on two cold nights, one with and one without a SB.
Last edited by BillyBob58; 11-01-2012 at 13:01.
Hmm, Interesting experiment! Weighing how much sweat soakes into my UQ. I'm curious what you wear to sleep as a VB? Rain Gear?
"Education is the ability to listen to almost anything without losing your temper or your self-confidence."-Robert Frost
, and the degree to which it acts like that depends on the wicking properties of the fabric, how much of the hammock bottom is exposed to air flow, and the balance of what your body puts out in perspiration against the fabric performance. This has come up in the design and production of hundreds of millions of mattresses, pads, and bottom sheets.
I'm glad BB58 (gently) included this alternative, vapor barrier (VB) explanation of reflective space-blanket effectiveness. Yes, I'm suggesting a black trash bag will be as effective or MORE effective as a space blanket in an emergency.
Hey Demostix, you got out of NJ in the nick of time!
Keep movin', keep believing and enjoy the journey!
i used a sb/vb on my last hang, and it made my last night out warm an toasty.
Glory to the Fallen, Honor to the Lost. Faith to the Missing. Carry on Forever.
Not sure I understand the concept of weighing the UQ. If the Mylar SB is between the hammock and the UQ, how would your sweat get into the UQ? Wouldn't that be condensation being created on the bottom side of the SB and is that where most people are seeing condensation with VB. I thought it occurred inside closer to the body and the insulating layers? I am completely confused now.
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