Sorry for this really noobish question but would a few layers of bubblewrap provide any kind of effective under-insulation in a Hammock? At least in terms of spring/summer camping. Just exploring all the options.
My Hammock and Tarp have finally arrived, looking forward to trying them out in the wild very much!
I tried my air mat in my hammock and it had no effect on keeping my backside warm. Think of that mat you used floating at the beach, a camping air mat is the same thing with a bit sturdyer covering. Real good for summer tent camping!!! Bubblewrap is just air, I can't see how it would do anything either.
The concept at work here is, I think, the idea of dead air space. I suspect the insulation value of something is much more complex than that. While dead air space does play a part in the in the insulation equation, I know different people have had different results using simply air mats.
Some folks have very good results using the windshield type reflectors that have a "bubble wrap" type core. Others have found them very unsuccessful. If I were going to try bubble wrap I think I would first do it in a "safe" situation. In other words, some where that I had a good trustworthy escape plan if need be. Then I would porbably want to combine the bubble wrap with a heat sheet or other reflective addition.
Different things work for different people. Give it a try and see what happens. Then let us know.
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Wasn't there a company that offered jackets with the same theory a couple years ago? Basically a wind shell that you would inflat to add more warmth.
None of these or air mats seem to catch on for insulation value. I think there is a reason for that. I remember somewhere either in a post or during a converstion, one of the Jacks talking about experiementing with it. I don't think it turned out to work very well.
Plus I think it wouldn't last more than a day and everyone around me would want to hit me after listening to me pop them the whole time.
Is that too much to ask? Girls with frikkin' lasers on their heads?
The hanger formly known as "hammock engineer".
Interesting. I've never tried it but I have been told bubblewrap can make a quite effective sleeping mat substitute for ground camping, maybe the physics are different for Hammocks somehow. Is it generally believed quilt-type insulation is better than the trapped air insulation?
I have used the mylar/bubble wrap truck window shade with surprising results. There are definitely better options out there but they do work for mild weather. I will probably use a small mylar/bubble torso pad for chilly summer nights. I would think a torso sized piece of this stuff could pack down pretty small.
I'm going for my first Hammock Camp this weekend so will experiment a bit, the weather should be mild enough, obviously I will bring some kind of back-up insulation if it proves useless.
Thanks guys,
Ian
Originally Posted by IanBristol
I get your question but you're actually talking about different varieties of the same thing. And that thing is.... [drum roll] air!"Quilt-type" insulation works by trapping air that is then warmed by your body heat. Generally, the smaller the individual spaces of trapped air, the better the insulation works. That's why a quilt with relatively small spaces of trapped air is warmer than the same thickness of an open-tube air mat. But add some open cell foam (like a Thermarest) or some down (like an Exped Downmat) to the inside of the air mat and the insulation value increases significantly because the air is trapped in small spaces which can be warmed easier than the previously large air space.
Ever notice that a CCF (closed cell foam) mat is thinner per insulating value than a quilt? So a 20* quilt in down might be 3 inches (7.6 cm) thick but a CCF mat good to 20* might be 1/2 to 1 inch (1.3 to 2.5 cm). Why is that? There are two reasons. First, the trapped air spaces in the CCF are a lot smaller than in the quilt - it's easier to heat the individual air pockets. Second, the air can't move through the CCF but in the quilt the air spaces are not necessarily completely closed from each other. Plus, when you move with a quilt, the air pockets and air flow are rearranged even if only slightly. And there is a third factor - the degree to which the CCF and quilt prohibit or inhibit vapor flow. The CCF is effectively a vapor barrier but it usually isn't wrapped tightly to the body. Still, you can get condensation at times, during which you also get a little extra warmth but it is mitigated when you move and expose the dampness (often on your back) to cold air where evaporative cooling kicks in.
Now the air pockets in bubble wrap are pretty large compared to CCF or quilt material. Plus bubble wrap is a single layer. To get better effect, you need muliple layers. And bubble wrap is make of plastic - the ultimate vapor barrier. Add in the fact that bubble wrap is not flat on both sides so one side or the other will have air running around all the bubbles. All in all, bubble wrap should insulate but to have decent results (if you can with bubble wrap), you would need several layers with an outer cover that both traps air to keep air movement down and passes vapor to help with condensation.
Bubble wrap also does not compress well.
By the time you go to the trouble to make what amounts to a bubble wrap quilt (with relatively large trapped air pockets), you would be better off getting some quilt type insulation to throw in instead. It will be warmer and more sturdy. And you won't have to fear others are going to sneak up and pop some bubbles while you are sleeping!
On the other hand, you could use bubble wrap to float your pack across swollen rivers...
Please do report back if you try bubble wrap. My thoughts are empirical, yours will be real-world!
Has anybody ever used the silver thermo emergency blankets under for heat. I know they work well inside a tent in a pinch. Reflect a lot of heat back. Just a thought.
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JayS is on track, but I would explain it a little differently. Insulation needs to prevent the air inside it from convecting (moving around). So insulation with many small pockets is better than large pockets. A normal air mattress is just one large air pocket, which allows the air to move around a lot so the air can carry away your body heat.
Another factor is how the insulative material itself conducts heat. A piece of metal with many small air pockets would still conduct a lot of heat and be a poor insulator.
Radiation is the third factor in insulation. Reflectix insulation is bubble wrap with sandwiched in foil, to limit radiant heat loss.
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