- This is my first post so this may have already been asked. I just
ordered a Hennessy Explorer and I am looking forward to using it.
Since I do most of my backpacking in the Sierras I am concerned about
getting too cold. It commonly gets below freezing anytime of the
year up there. Has anyone ever tried laminating a space blanket to a
thin foam pad. I see David Olsen of Oware sells a pad 40" wide by
60" long by 1/4" thick. This seems an ideal size for a pad because
it would also wrap up around your shoulders. If I laminate a space
blanket to it to get the reflective heat thing going, this seems
ideal and also very lightweight. Any thoughts?
- Hi Todd,
Welcome to the group. I think just about everything has been tried
with every result from dismal failure to excellent results. It seems
that the best idea so far for the really colder climates is the
external hammock wrap. Do a search on this board for Pea Pod or
The biggest problem seems to be the ability to handle condensation.
If you insulate the inside of the hammock enough to protect your
backside from the cooling effect of the air under the hammock, you
trap all the moisture from your body underneath you. The external
insulators seem to eliminate that problem from what I have read.
I'm sure you'll get many positive opinions about space
blankets. However, my personal opinion is that space
blankets have NO heat reflecting properties in our
application. They act as wind barriers only. Since your
closed-cell pad is already windproof, I don't think the
space blanket would add anything.
The foam pad sold by David Olsen is great -- hard to beat
the size. But for lower temps you'll want 3/8 or 1/2 inch of
padding underneath you, whether by combining layers or by
using a single, thick pad.
I've used a single thickness of the Olsen foam to keep my
shoulders warm, down to the high 40s only, and it works fine
for that. It may work at even colder temps, but I just don't
have any personal experience to report.
- Bear, Todd,
My take on reflective coverings:
Experimentally, I found a "Refletix" bubble wrap/reflective pad to
not be as warm as a Target blue 3/8 inch closed cell foam pad.
just like with a thermos bottle,
If you can arrange a reflective layer such that
a) it is not in contact with what you want to keep warm and
b) it is not in a chamber which has convection currents
Then it may add something to warmth.
A practical way to do this might be to put a space blanket in a
hammock, cover that with a closed cell pad, and then sleep on the
pad. The space blanket may add something as a reflector of Infrared
light leaking through the pad back into the pad... To the extent
that the surface touching the space blanket is air filled bubbles and
not heat conductive plastic strands. Get the outside of the pad wet
with condensation (great conductor of heat) and it would cause the
space blanket to lose almost all it's potential effectiveness.
Another practical way to do this would be to use a layer of refletivx
between the hammock and a foam pad... But analysis of that is
complicated by the multiple bubbles etc...
Bear is completely correct as far as a space blanket being useless if
the warm object is actually in contact with the relective layer... in
that case, the heat is simply conducted through the thin layer just
like it conducts directly through the hammock material to begin
with. So sleeping on the space blanket does just about nothing.
Practical conclusion: I believe most will find the utilty of using a
reflective layer rests more in the air it traps than the use of the
--- In firstname.lastname@example.org, "David Chinell"
> I'm sure you'll get many positive opinions about space
> blankets. However, my personal opinion is that space
> blankets have NO heat reflecting properties in our
> application. They act as wind barriers only. Since your
> closed-cell pad is already windproof, I don't think the
> space blanket would add anything.
> The foam pad sold by David Olsen is great -- hard to beat
> the size. But for lower temps you'll want 3/8 or 1/2 inch of
> padding underneath you, whether by combining layers or by
> using a single, thick pad.
> I've used a single thickness of the Olsen foam to keep my
> shoulders warm, down to the high 40s only, and it works fine
> for that. It may work at even colder temps, but I just don't
> have any personal experience to report.