space blankets for insulation

[rondog]

So, there's two kinds of "space blankets"? The thin mylar-looking things and a military type? Where can a guy get the military kind? I need to get some to keep in my Jeep.

[StagLefty]

So, there's two kinds of "space blankets"? The thin mylar-looking things and a military type? Where can a guy get the military kind? I need to get some to keep in my Jeep.

I think you can find them at most box stores in camping dept. I carry the thin ones in my bags but have the heavier type in the truck all the time.

[rondog]

Kewl, thanks! I'd resisted buying the mylar kind because they're so flimsy I figured they were worthless, but I didn't know there was a heavier military version. Them's what I need.

[Tim K]

Heat is transferred three different ways. They are:

Radiation - Like when you feel the heat from the sun or a fire

Convection - Moving air across a surface. A cold wind is an example of convection cooling.

Conduction - Contact heat transfer. Sticking your tongue to a flagpole in winter is a pretty good example.

Some combination of the three is at work in almost all situations. In the hammock illustration, heat will be transferred away from the sleeper primarily by radiation and convection. Conduction is not a significant issue because you are not sleeping on the cold ground.

Space blankets work primarily by limiting radiation of heat. They're marginally effective at limiting convection cooling, and totally ineffective with conduction. As a result, adding one will be better than nothing. Determining how much better is the job of a specialized engineer and a super computer.

[StagLefty]

I refuse to put a specialized engineer & a super computer in my BOB

[68Charger]

I refuse to put a specialized engineer & a super computer in my BOB

Technically, I'd have a specialized engineer carrying my BOB

(as long as you don't specify the specialization of the engineer)

[tmckay2]

thanks for the replies. lets try to keep something in mind and help me formulate a good option for what i am looking for. sure, you could use a foam pad or something, even a fleece blanket, and those aren't off the table, but remember that these take up a significant amount of room (although they are fairly light). we want to minimize the weight and size which is why these small space blankets SEEM like a good idea. however, because they are so thin it does make sense that they would do little to stop convection. but, they are about the size of my hand and weight almost nothing. are they supposed to be disposable or is it simply that they are too flimsy to be used again? what are some other options?

i could make something that is super insulating, but large. i could make something thats not insulating but is small. the trick is finding a medium

[Tim K]

Actually, I think they'll do more than I may have led you to believe concerning convection heat transfer. They are wind proof so they should stop any evaporative cooling, and they will probably be much better than nothing. I'd try it before you rule it out.

[rondog]

Oh, this is for a BOB? I thought it was a camping question. Disregard my Reflectix suggestion, although that stuff would be great on the floor of a tent.

[tmckay2]

no its for camping but i rarely car camp, i usually back pack. so in other words, the lighter and smaller the better. thats why i even switched to a hammock. its insanely smaller and half the weight of a normal backpacking tent. probably half the size too.