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Re: [at-l] question for winter campers

> Phil Romans wrote: I was still kinda cold.  I even had on my lightweight capline undies
> > on.  What is the correct approach to handing this colder question?

Hiya Phil.

This is the way it was explained to me:
Think of you body as a radiator.  The bag is the insullation in the 
walls of your house.  The job of the radiator is to heat the air inside 
the bag.  Ergo mummy bag's popularity because there is less air to heat.

If you insulate the radiator, enclose it in something (like clothes on
the body) you trap much of the heat which prevents it from doing the
job of heating the air inside your bag. Your body will stay warm,
(just as an enclosed radiator will stay warm) but you will not be 
comfortable because the air around you is cold.

If the insulation of your bag is insufficent, just like a poorly 
insulated house, and the radiator can't generate enough heat, if
you wear a_loose_fitting_layer, you can create a extra 
heat trapping area which is easier to heat(kinda like throwing a 
sheet over the radiator and crawling into the smaller space you have
created).  Or you can throw a piece of plastic over the radiator and
be warmer still..  This heat gain is not so much because of extra 
insulation but because it limits infiltration of the colder air
into the area directly near the skin. For more heat gain use a non-porus 
layer which stops infiltration totally... ergo VBL's.

After reading this back I have to say the gear guy explained it better
than I have. But I agree with Felix in that I keep a layer on until
the bag warms up then wriggle out of them to let the radiator do it's
job.  
Also...if you heat up some water and seal it_tightly_and tuck it in the 
bag it will help warm things up before you get there.  Works great if
your boiling water to purify it anyway.
And eat something before you go to bed.  Digestion equals work for the 
body which must burn caloeies which creates more heat then just lying
there.  Exercise will do this too.  Keep warm    YMMV..     Kahley
PS......I always need socks on ...big problem with a rect. bag.
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