Oct 10, 2013 at 1:43 pm #1308578
Max DiltheyBPL Member
Ok, so I'm going back out on tour (again, again, again) and I'm looking at the space blanket on my floor, thinking "What the hell do I use this for?"
I've got synthetic insulation, and the good sense not to get soaked. So will I really need this thing? It's like four ounces. I understand the science (sort of…) but I see a lot of companies putting reflective layers in stuff. Both my thermarest pads have it. It's starting to look like a gimmick to me. Am I wrong?
Does it really make a big enough difference to warrant the weight, or can I ditch it if i'm within my sleeping bag's "Extreme" range the entire trip?Oct 10, 2013 at 1:45 pm #2032832
Justin BakerBPL Member
@justin_bakerLocale: Santa Rosa, CA
Space blankets are pretty useless for keeping you warm, the bivy space blankets are much better.
I sometimes tape a space blanket to my tarp to reflect heat from a fire. It works amazing for that.Oct 10, 2013 at 1:51 pm #2032833
@b-g-2-2Locale: Silicon Valley
A space blanket can be effective in blocking radiated heat loss, but that is less than 10% of your total heat loss. It is as effective as a good sheet of plastic for blocking convected heat loss, so it is not worthless. It is a good rain cover in a storm.
I've used one as a ground sheet when I didn't have a better piece.
–B.G.–Oct 10, 2013 at 2:14 pm #2032842
Brett PeughBPL Member
I use one above 60F for warmth and at lower temps as a VBL with my quilt.Oct 10, 2013 at 2:16 pm #2032844
I've carried one for years and never used it, wonder if it wouldn't be better to leave at home.
It provides a little warmth. It provides more warmth for the weight and volume than anything else.
If you have a tent and sleeping bag it's probably not important to take. In a survival situation just use those.
If you're day hiking it could save your life in a survival situation.Oct 10, 2013 at 2:35 pm #2032852
@rosyfinchLocale: the mountains
I spent a night out once down in the low 20's clothed in shorts and T-shirt.
Wished I had a space blanket or bivy back then. :)
Bill D.Oct 10, 2013 at 2:37 pm #2032853
John MyersBPL Member
@dallasLocale: North Texas
"If you're day hiking it could save your life in a survival situation."
What Jerry said.
I've stopped carrying them when backpacking.Oct 10, 2013 at 2:40 pm #2032855
Dena KelleyBPL Member
@eagleriverdeeLocale: Eagle River, Alaska
In most instances, yes I have a space blanket. They are in my vehicle, in my PSK, and even hanging on the backside of my greenhouse (increases the internal temperature of my greenhouse). When backpacking with all my camping gear, I consider the space blanket to be redundant and don't carry it but in the winter I do carry it as a ground cloth (I use snow shelters in the winter, not tents).Oct 10, 2013 at 2:49 pm #2032857
Justin BakerBPL Member
@justin_bakerLocale: Santa Rosa, CA
The blanket is difficult to use. It's so light that you can't wrap it around your body well, especially not if you are putting it over your bag. The bivy version is so much better.Oct 10, 2013 at 3:00 pm #2032863
Max DiltheyBPL Member
Cool. Confirms what I was thinking. Definitely useful to have in a dayhike bag, but redundant when backpacking and camping.Oct 10, 2013 at 3:32 pm #2032869
Justin had some good suggestions, but I think where a reflective sheet is really going to shine (pun intended) would be as a partial VBL under a quilt and directly over the body during cold temps to boost ones sleep system. Think Michael L's earlier thread with using Cuben and it helping a lot, but instead using the reflective stuff. I've experimented with S.B.'s before but not quite in that way yet. But it seems clear that would be of the most efficient ways to use it besides reflecting fire heat.Oct 10, 2013 at 4:03 pm #2032879
"but I think where a reflective sheet is really going to shine (pun intended) would be as a partial VBL under a quilt"
This may be controversial, but I think there needs to be an air space next to the space blanket to be effective.
If there's something against the reflective layer, it will just conduct heat and reflective layer won't make any difference
If the space blanket is on the outside that works. There's an air space on the outside.
If you could have an air space and then space blanket, that would work, but how could you suspend the space blanket? The Blizzard Survival Suit accomplishes this by having an accordian fold with elastic, but that's sort of heavy.Oct 10, 2013 at 5:51 pm #2032917
+1 with Dena
Usually you'll have a fly or ground cloth or tarp for wind and rain protection.
I carry them in my day packs. Colorado is known for 40 to 50 degree temperature swings at elevation. Mix that with a little August snow fall and you might catch a chill.Oct 10, 2013 at 6:06 pm #2032926
That's interesting Jerry, i didn't know that. I would still like to test it out.
Guess Columibia is scamming folks then with their reflective liners and claims of enhanced warmth?Oct 10, 2013 at 6:25 pm #2032934
Like I said, the air space to make reflective layer effective theory seems to be controversial for some reasonOct 10, 2013 at 6:29 pm #2032937
I tend to prefer the bivvy configuration. I use the old space blankets I have lying around for ground sheetsOct 10, 2013 at 6:32 pm #2032940
How does the concept work? Does it matter at all how the reflective layer is made besides the accordion part? What i mean more specifically, is i just got some SOL emergency blankets, they are reflective on one side and solid color on the other side, as opposed to the regular mylar space blankets. Would that make any difference at all, or do you just need some kind of air space?
I'm trying to figure out how this works, and my brain is just not working very well so far doing it.Oct 10, 2013 at 7:11 pm #2032954
@m-lLocale: W-Never Eat Soggy (W)affles
I prefer a blanket type vbl, less sweaty.Oct 10, 2013 at 8:19 pm #2032976
What's important is reflectiveness in the IR spectrum. It may be a solid color in visible wavelength, but reflective in IR, I don't know.
You want an air space next to a reflective surface for it to work.
I would put the solid color surface against me (my clothing) and the reflective surface facing out.
If you look on the web, you can frequently see photos of people with space blankets with a colored surface on the outside. If that colored surface is not reflective in IR, I think that won't work, they should have the shiny side out, not the colored side. Radiant heat loss is sort of obscure, so maybe they're just making a mistake in usage, which is funny since they're selling it. They should show how to use it properly.
If there's a shiny side facing you, there is some air gap because of wrinkles and such so that works some.
And, like I said, I may get some disenting opinion about this : )Oct 10, 2013 at 8:43 pm #2032983
Ok, i think i see what you mean a little better, especially as far as the air gap. Like an air gap between you and the S.B. That part makes sense, i thought you were saying you had to have a clear air space behind the S.B. to work.
Well there are ways to create some air gaps i suppose, rolling up some clothes into a tight roll placed over your body, but then you got to sleep like the dead, so not very practical i suppose.
Why does nature hate us so, why, whhhhyyyyy..???? Can't things be easy, light, effective, and cheap?
Why are we such wimpy creatures, with so little natural adaptation? Wolves don't have to hang around gear forums figuring out, "Gggrr arff arrff ruff ruff ruff Ah oooooh(translates) "Well Bob, let me tell you, i got these new down booties, and they are dah bomb, super light, super warm, and it only cost 3 rabbits. Can you believe it?"Oct 10, 2013 at 9:12 pm #2032991
clothes don't create air space. As soon as IR hits the surface of the clothing it gets absorbed. You need an air space that consists of air.
A blizard suit has several layers of reflective material, then they're accordianed up using elastic. So you have reflective material, air, reflective material, etc.
A neo air mattress has internal reflective layers inside, suspended so there's air space between.
In the ceiling of a house, you can suspend the reflective material between joists so there's air spaceOct 10, 2013 at 9:50 pm #2032997
Got you, got you before too, but i guess i wasn't explaining myself well. In any case, what i was saying wouldn't really be practical anyways.
Probably also not practical; I guess one could put guy outs on a S.B. (one of the stronger SOL ones) and raise it up an inch or so from your body, but what a pain in the butt.Oct 10, 2013 at 10:18 pm #2033004
My great idea is to make a tent out of reflective material
Theoretically this should workOct 10, 2013 at 10:24 pm #2033007
Sounds interesting, i'm guessing there's no current suitable material?
Funny enough, i have been thinking of making a reflective liner for my Tipi tent, but i don't know how to do it with the stove being set up inside same. I don't think putting it any where near the pipe would be a good idea.
But maybe i can just sort of hang some from the top sides and reflect it down. Probably don't really need it to begin with the stove in there. Get's plenty hot, but more interested in conserving the heat a little longer.Oct 10, 2013 at 10:51 pm #2033018
The outside of a clothed or sleeping bagged body is only slightly warmer than ambient so heat loss from radiant heat loss is small – what did someone say, 20% of total heat loss?
A stove is hot. Radiant heat reflected would be a lot more.
You can buy space blankets.
Go to a store that sells stuff for growing (marijuana) plants indoors. They sell reflective material.
You must be logged in to reply to this topic.