many of the BPL drying tests on down are done assuming one has proper "drying conditions" … ie the sun
ive not seen a BPL test yet done on trying to dry down without the sun or a decent breeze … id would love to see one …
and of course, most of these BPL tests are on THINNER garments with a few OZ of down, not big thicker puffies or sleeping bags …
also just because a WM flash dries quickly doesnt mean some other jacket will …
The wet performance we observed in the MontBell Down Inner jacket supports the assertion that higher volumes of down and a less breathable shell will reduce the wet weather performance of a down garment. The Down Inner jacket has a higher volume of down than the Flash and lofts to 2.8 inches of double layer loft. Its shell material is MontBell's Ballistic nylon. Ballistic nylon threads are calendared. They are heated, then flattened and widened. This improves abrasion resistance and reduces down leakage, but also reduces breathability and slows the drying rate of the Down Inner jacket. (The calendared fabric is closer to a non-breathable/waterproof fabric). The Flash vest with non-calendared fabric reached 1.3 inches of double layer loft after 30 minutes, exceeding the loft of the synthetic Micropuff. But the MontBell Down Inner Jacket with calendared fabric took approximately 100 minutes to recover to 1.3 inches of loft.
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Synthetic insulation is far superior to down when both are fully saturated.
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Most other down-filled products will not recover from becoming wet as quickly as the Flash vest due to more down mass in relation to surface drying area..
http://www.backpackinglight.com/cgi-bin/backpackinglight/wet_weather_performance_down_vs_synth_vests.html
here is a real life BPL description of the effects of internal condensation on down when you CANT dry it due to lack of sun even in mild conditions ….
The next several days were no better. After a half-day in the town of Packwood, we were back on the trail with dense clouds and no views. Our tents were soaked every morning from condensation, and it became harder and harder to dry our things out every day. My sleeping bag’s loft started to weaken little by little as humidity collapsed the down, and I was forced to sleep in layers even on relatively warm nights. Those warm nights, however, began to vanish soon after Packwood. With 100% humidity and temperatures dipping into the high thirties each night, my main motivation became the next stop in town.
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In the morning, we had the now all too familiar experience of packing tents that were soaked with rain on the outside and condensation on the inside. Then, as we walked up the trail, our clothes became saturated by what Tangent began to refer to as the “car wash effect.” Even with only small amounts of rain in the night, the water collected on leaves of bushes and shrubs, which leaned into the trail and sprayed us as we pushed through the mess. Every morning started with drenched feet and pants, depending on how much rain gear we felt like wearing.
http://www.backpackinglight.com/cgi-bin/backpackinglight/hiking_through_hyperbole_part4_walk_in_the_clouds.html
from another BPL article ….
On a multi-day trip, critical attention must be paid to minimize the moisture that accumulates in your sleep system as each night passes. Weather permitting, you should take the opportunity to air-dry your sleeping bag and bivy sack every morning. This technique is important even in sub-freezing winter conditions – but only in the presence of bright sunlight. Solar radiation will provide the heat energy required to drive the evaporation of moisture from your gear
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But alas, as weather is notoriously uncooperative, you should consider your clothing and sleeping bag loft as a consumable but renewable resource and take steps to actively manage it like you would, say, your drinking water. Be opportunistic and dry gear whenever you can on an extended trek!
http://www.backpackinglight.com/cgi-bin/backpackinglight/bivy_sack_techniques.html
again what i would love to know is short of having a synthetic overbag and an excess of heat (fire, hawt nalgene) how do you dry down without the sun when your sleep/clothing system is already at the limit of its temperature rating
now that would be an AMAZING BPL article
;)