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(This might be a bit long. Please read to the end before drawing conclusions.)
The Shocking Blue arrived Friday. The first thing that strikes one is that this is not a bag made to hang in a gear shop and look plumply seductive. The fabric holds creases, more than any other I've seen used in sleeping bags, and, laid out with no one in it, the anatomically shaped baffles collapse slightly and form miniature canyons that run the length of the bag.
The color, as people have noted, is no longer shocking (or Lego) blue, but a reserved grayish-blue. Of course this has nothing to do with the bag's function, but may reflect an evolution in the designer's sensibility.
There's a degree of intricacy to the bag's construction that's unusual. The hood, the collar, the long (and, by BPL standards, probably a bit weight-expensive) zipper storm flap, all seem thought-through and chosen to create a product that will work in an extreme environment. By contrast, most other bags have a more unified look, but don't look nearly as "tough" or "functional". The wrinkly fabric choice is consistent with this--it looks like it will loft better than 1.1 oz nylon, maybe not quite as well as 1 oz Pertex Quantum, but be tougher than either. Breathability seems between the two, but of course I can't tell how it works with water vapor.
The hood is superb. It adjusts easily and precisely. In the "locked down" position, the down of the hood is, as far as I can tell, completely uncompressed, and the lower portion of the opening moves naturally to below ones mouth so that one isn't breathing moisture into the down.
When one is in the bag, it does collapse around ones body, removing excess air, much more than I remember of the first generation fabric bags, and more than the "bottle-shaped" WM Antelope or FF SnowBunting (rated by their manufacturers at 5 and 0 degrees, respectively), not quite as much as the Nunatak Arc expedition (rated 5 degrees), which is of course a quilt.
The down tubes from the foot box to the knee are quite plumply filled, as are the tubes of the hood. Baffle height in the first few tubes of the foot box seems to be 3 or 3+, dropping to 2 or 2+ in the knee region, then rising again as one goes up the bag. Baffle spacing is about 5.5", with the two of the three chest baffles being 6" and the third 6 1/4". These wider-spaced baffle areas above the chest give the impression of being less fully filled, (and explain some of my early reservations) but perhaps that's just because the down has more room to move around. In contrast, the FF Snow Bunting, Nunatak Arc Expedition, and WM Antelope use, in the bags I have access to, spacing of 5" and height more consistently around 3"-3.5" (Nunatak). (The baffle height numbers are very tentative, and could be dead wrong; one definitely has the sense that the baffle height is greater with the American bags, though, with the Nunatak's being the tallest.) (Less baffle material, all other things being equal, means smaller stuffed size.)
The down feels quite different--when one gently collapses a tube, between the palms of ones hand, in feels gossamer and unspringy. (The Nunatak down feels very similar, maybe a bit springier). The WM and FF down are much springier, resisting compression, pushing back against ones palms.
And here we're getting, I think, to the crux of the issue. In order for the Valandre to be a significantly warmer bag than, for example, the WM Antelope, it must rely on its collar and its down quality. Its draft tubes are no deeper, nor is its down weight/cubic inch greater, and may be less. Its total down load is very similar--28 oz in the Antelope, 27.5 in the SB, size large. But the SB is significantly wider in the chest region, so the down there is necessarily, and perceptibly, less dense than in the chest region of the Antelope.
Valandre claims their fill power is 850 plus. (In fact, judging by its feel, it may be significantly plus.) There's an extraordinarily useful, but occasionally quite technical forum thread here: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=16189&disable_pagination=1
(In particular, read the contributions of Richard Nisley.)
from which I take away the following: First, for a given quality of down, the density with which it is stuffed, within the normal densities of stuffed and overstuffed bags, does not affect the down's insulating quality per unit weight. In other words, the same volume of bag, stuffed 10% fuller, will be 10% warmer. A given weight of down will not be made much warmer by letting it loft higher.
Second, the effectiveness of down as an insulating material, relative to its weight, is a function of its "fractal" quality, the number of ends each piece of down has. At one end of the spectrum, a strand of synthetic has two ends; at the other end, very very fine down might have way more ends than very fine down. In the middle, feathers, or feather-like down, "spend" too much of their weight in their quills, which don't grab the air. Down works, after all, not as a magic "heat shield", but as a damper of the moving-air cells that would carry heat away from the body.
Third (and this is purely my contribution, so if it's wrong, blame me): we know that down is adaptive. When warmed, for example, down uncoils--put your bag in the sun to dry out, and it plumps up. After drying, put it in the shade, and it collapses slightly.
And here's the speculative part. Maybe down is even more adaptive than that. Maybe down can "sense" heat differential, and become better-insulating as the temperature differential between the goose's body and and the environment decreases. There would definitely be an evolutionary advantage to down that was so "designed." When the goose is flying, or running around, it doesn't want to over-heat. Some of this regulation is, of course, supplied by the cover feathers, which can be made more open or closed by changes in the gooses skin. (Think of "goose bumps.")
And maybe, the higher the quality of the down, the more adaptive. I do know that in a 16 oz Nunatak quilt (like the current Arc Specialist), sleeping on a 3 oz Gossamer Gear pad, I was OK--not warm, but OK--down to an in-tent temperature of 14 degrees. But with that same quilt, I'm not boiling at 40 degrees. Similarly, one can be in the SB or the Arc Expedition at 60 degrees, with everything but the SB's hood cinched down, without boiling--just barely too warm, but OK, at least for 20 to 30 minutes. In contrast, I quickly start to feel too hot in other Mfgs low temp bags, at 60 degrees.
So the upshot of all this is that I'm inclined to trust the reports of the other posters here who've used Valandre bags in extreme conditions, but won't know for sure until I try the SB myself. To that end I'm going to try to find a -15 degree walk-in commercial food freezer, and will let you know. If things go horribly wrong, you may find me ground up in some supermarket as sausage.
Another note--one retailer I spoke with suggested that, as European consumption patterns are different from ours, there's an incentive to make items with a wider range of application. The SB, and Mirage, have greater torso volume so that one can layer, and, by the logic of Valandre's primary markets, it doesn't make sense to make "non-layering", more mummy-like bags as well. In another thread this same explanation is given to account for the preference among Europeans for double-walled tents . We think nothing of owning two or three tents, for different conditions; they only own one.
Edited by swimjay on 11/24/2008 10:22:59 MST.
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