In article . rogers.com,
Michael Daly wrote:
Heat loss is irrelevant compared to this.

Not so. If the Sleeping Bag is rated for -10C, the Vapor Barrier
lowers the rating to -20C. But because there is no danger of water
condensation, you can use water-proof Bivouac Bag also, which further
lowers the rating to -30C.

In case of emergency it is good to know that couple of heavy duty
garbage bags can turn your 100 euro backyard bag into $400 polar bag.

Timo Noko wrote:

In article . rogers.com,
Michael Daly wrote:

Heat loss is irrelevant compared to this.


Not so. If the Sleeping Bag is rated for -10C, the Vapor Barrier
lowers the rating to -20C. But because there is no danger of water
condensation, you can use water-proof Bivouac Bag also, which further
lowers the rating to -30C.

In case of emergency it is good to know that couple of heavy duty
garbage bags can turn your 100 euro backyard bag into $400 polar bag.

Agreed. I use a lightweight bag that is normally comfortable down to about
30 F. If it'll be colder than that I use a vapor barrier inside and that
way I've been comfortable down to nearly 0 F. It's a very inexpensive and
lightweight way to increase the low-temperature range of the sleeping bag.
Also cuts down on water loss overnight so I'm not as thirsty in the morning.

On 22-Dec-2003, Peter wrote:

Heat loss is irrelevant compared to this.


Not so.[...]

Agreed. [...]

My point is that if there is no vapour barrier, then soaking your
insulation is a serious problem, whereas adding the vapour barrier
only increases the temperature rating a bit. If you want warmer,
buy a heavier bag; if you want dry insulation, get a vapour barrier.
Increased warmth is a byproduct of using a vapour barrier, not a
reason for buying one.

Mike

On 22-Dec-2003, "Rick" wrote:

As you point out, any bag that is wet and then freezes may function as well
as an igloo,

Poor analogy - actually, igloos and quinzees can be nice and warm (well,
compared to a tent or open air).

Your other points are valid - using a vapour barrier at higher temperatures
than ideal may increase your warmth, but decrease your comfort. I wouldn't
use a VB until the temp is cold enough to warrant worrying about wet
insulation from insensible perspiration.

Mike

Michael Daly wrote:

On 22-Dec-2003, Peter wrote:


Heat loss is irrelevant compared to this.


Not so.[...]

Agreed. [...]


My point is that if there is no vapour barrier, then soaking your
insulation is a serious problem, whereas adding the vapour barrier
only increases the temperature rating a bit. If you want warmer,
buy a heavier bag; if you want dry insulation, get a vapour barrier.
Increased warmth is a byproduct of using a vapour barrier, not a
reason for buying one.

It was for me. I didn't have a problem with my insulation getting wet, but
sometimes it was getting a bit cold for the rating of my bag. Your
suggestion would have cost me a couple hundred dollars for another bag and
added another pound to my pack. A vapor barrier cost less than $10 and
added only a few ounces. Also doubles as a useful item to have for
emergencies on dayhikes just in case you need to bivouac somewhere (which
is why I got it initially). I only heard that it was called a vapor
barrier and that it solved the wet insulation problem from condensation a
few years after I started using it for the added warmth.

Timo Noko wrote:

The answer is VAPOR BARRIER. This is an air-proof bag you use inside
the sleeping bag to keep it dry from perspiration. In extreme
coldness the sleeping bag frozes within minutes and any moisture just
cannot get out.

Of course there is slight discomfort sleeping (preferably naked) in
your own sweat. Propably not very good for Brian who seems abhor his
own stench above all.

I have no problems with vapor barriers, I just refuse to stew in my own
sweat in a neoprene suit. One can easily wear light underwear in a vapor
barrier bag and be quite comfortable.

You seem to have a passon for suffering unnecessarily, Timo. But hey, if
that's what floats your boat, more power to ya'.

--
Regards

Brian

In article ,
Brian Nystrom wrote:

You seem to have a passon for suffering unnecessarily, Timo.
But hey, if
that's what floats your boat, more power to ya'.

No, it is them others who are the masochists. I was kicked out of
Yahoo's Bagboater's Club because I could not stop laughing at Jon
Waterman's arctic adventures. One of his complaints was that he
cannot use wetsuit socks because of trench foot. And now from the
abovementioned Vapor Barrier - site I read that one of discoveries of
the US Army was that the wetsuit socks are the bestest way to prevent
and cure this ailment...

"Michael Daly" wrote in message
t.cable.rogers.com...
On 22-Dec-2003, "Rick" wrote:

As you point out, any bag that is wet and then freezes may function as
well
as an igloo,

Poor analogy - actually, igloos and quinzees can be nice and warm (well,
compared to a tent or open air).

....stuff deleted


Mike,

You snipped off the rest of the sentence, which said, essentially, that
igloos, while effective, are difficult to fold into the kayak. I guess
Ididn't make that part clear.

From what I've read, igloos can be very effective, though I've no experience
with same. I have dug snow tunnels, however, and they are downright balmy if
you are dressed appropriately.

Rick

On 23-Dec-2003, "Rick" wrote:

You snipped off the rest of the sentence, which said, essentially, that
igloos, while effective, are difficult to fold into the kayak. I guess
Ididn't make that part clear.

Or I read too fast - sorry. I prefer to use the snow that's there, no
need to carry any around :-)

From what I've read, igloos can be very effective, though I've no experience
with same. I have dug snow tunnels, however, and they are downright balmy if
you are dressed appropriately.

What I love about them is sleeping in absolute darkness with absolute silence.
I have not experienced that in any other environment.

Mike

Timo Noko wrote:
In article ,
Brian Nystrom wrote:

You seem to have a passon for suffering unnecessarily, Timo.
But hey, if
that's what floats your boat, more power to ya'.


No, it is them others who are the masochists. I was kicked out of
Yahoo's Bagboater's Club because I could not stop laughing at Jon
Waterman's arctic adventures. One of his complaints was that he
cannot use wetsuit socks because of trench foot. And now from the
abovementioned Vapor Barrier - site I read that one of discoveries of
the US Army was that the wetsuit socks are the bestest way to prevent
and cure this ailment...

I don't know what site you're referring to, but I still see no reason
for being wet when one can just as easily stay dry and eliminate the
possibility of such ailments.

--
Regards

Brian