I was wondering if I take 2 flannel sheets and sandwiched a space blanket between them and sew around the edges if it would deminish the effects of the space blanket.

It would make the blanket wind/waterproof...

But yor'd still end up with a waterproof barrier that would collect the water vapor your body put off, with the result that the inside flannel sheet would end up wet.

Why not use something like a Thermo-Lite Bivvy sack? Its already soft to the touch and wind/water resistant.
Emergency blanket will most likely rip before you can finish the sewing process.

There is no doubt that the Thermo-Lite Bivvy sack is better (I often carry one of their double sized ones for myself and my wife tro fit in. Misery loves company), but while much tougher, and probably more effecient, it is also much larger than a couple of space blankets. So, while I don't always carry the bivy, I always have a space blanked tucked into my day pack, and usually in a cargo pocket of my pants...

That is interesting, I would have thought that as long as body heat was held in and wind held out a space blanket would work. I had assumed (always a bad thing, I know) that the inner layer of fleece/flanel/wool/whatever, would just absorb some of the sweat you are probably going to generate. Ya learn something new every day...

Or you could just get something like this:
River's west H2P material

On their website, select the hunting gear tab on the upper left, then the accessories, then the blanket. Alternatively read about their product specs while browsing their site.

This stuff can't be beat for foul weather. I've had one of their blankets for almost 4 years now and it is as good as the day I pulled it from the box. I've used it as a shooting pad, as a ground cover, as a wrap at elk camp, but my wife uses it as a throw to snuggle in with the dogs at home in her favorite chair. We call it the pacifier because after 5 minutes in it, she is sound asleep, and so is the pooch.

I've tried to poke holes in it with sticks and wrestled it from the lab's jaws in tug of war sessions on the living room floor. It still doesn't show signs of damage or wear.

I grew up with wool everything; wool army pants, wool pendleton shirts and jackets, wool socks. Growing up at the base of Mt. Rainier in the Pacific Northwest, I just accepted that I could stay reasonably warm but forever wet in wool. I'll take the H2P garments over wool from now on, thank you very much.

"... skin to foil contact ..."

I wonder if that's really true?

I used to have a great Ford panel van that had been insulated by the previous owner. When I got the Dodge window van, I was sleeping in it in the Cascades when the temps dropped and I nearly froze. I opened one of my El Cheapo emergency blankets and pulled it over my bedding. I was much more comfortable in a few minutes.

It crackled like a baby playing with cellophane, though.

Sue

Benjamin what does the blanket weigh?

How heavy is that thing?
I couldn't find it on the site.