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What's the benefit of synthetic?
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Brian UL

Locale: New England
Re: Re: Wet Down vs. Wet Synthetics on 09/20/2007 05:39:20 MDT Print View

I think the susceptibility of down in wet conditions is vastly overstated. Down has some natural water resistence, if you get the surface of your bag/clothing wet it will dry without much trouble. Surface meaning not thru-and-thru wet. Also a good water resisitent shell goes a long way.
The only advantage of synthetics besides cost is the abillity to ring and sqeeze the water out.
If your bag is soaked to the core like that than you had to have done something really, really stupid.

Edited by MAYNARD76 on 09/20/2007 05:48:14 MDT.

Brian James
(bjamesd) - F

Locale: South Coast of BC
Re: Wet Down vs. Wet Synthetics on 09/20/2007 10:42:13 MDT Print View

I think it's understated.

Last winter I changed my dry body into dry clothes, laid down in my dry down bag in my dry well-ventilated tent, and drifted off remembering that it was humid so I'd have to wake up and check for condensation.

In the middle of the night, a cloud drifted into my tent. I had proper low-high ventilation arranged and I was ready for humidity. But I could actually see the wisps of cloud/fog moving around the tent and drifting in the vents.

If I'd closed the tent up any more, I would have been in a condensation bubble.

By morning, my down bag was like a sack of wet leaves. Whereas it was previously at its' maximum compression in its' stuff sack, it now took up *half* the stuff sack.

I was camping on 15' of snow, and there was wet snow falling. There was no *way* I could have dried it out. I thanked the deities that I was just on a gear-testing overnighter, strapped on my snowshoes, and got the heck out of there.

As stated, if it had been synthetic I would have at least had a fighting chance. But if your METTT involves humidity that hovers just above or just below freezing, you could reach the failure point of your down despite doing everything right.

Synthetic just has a more extreme failure point in terms of humidity/moisture saturation. Also, it's possible to bring it back from the dead using body heat.

Ross Bleakney
(rossbleakney) - MLife

Locale: Cascades
Advantage of Synthetics in Thin Clothing on 09/20/2007 10:46:43 MDT Print View

I don't know much about making clothes, but it was my understanding that synthetic gear could be made without a "shim", thus making the construction (not counting the fill) lighter. I think the Cocoon gear used to make a claim based on that idea (something like "for this weight, it is actually warmer than down"). Of course, even if you gain a little in construction, you would lose it once you started adding more insulation. In other words, a very thin synthetic might be warmer than a down jacket of the same weight, but once the jacket gets thick, the down is lot warmer. I've noticed that the Cocoon gear is no longer sold with this claim. This makes me wonder if the original claim was unfounded or the jackets are heavier (thus making a down jacket of the same weight warmer).

Ryan Gardner
(splproductions) - F - M

Locale: Salt Lake City, UT
Addition of bivy... on 09/20/2007 10:49:36 MDT Print View


What does the addition of a bivy do for a situation like the one you just described? What about when you are under a tarp?

Johnathan White
(johnatha1) - F

Locale: PNW
Re: Wet Down vs. Wet Synthetics on 09/20/2007 11:28:12 MDT Print View

I too slept on 15' of snow at the base of Mt. St. Helens one winter with my 7 year old. Night time temperatures dropped to 18F with daytime temps peaking around 42. We were in clouds by nightfall. As we were protected by trees, there was not much wind through the night in our 4 season double-walled tent. I had with me a down Marmot Lithium sleeping bag rated at 0F.

I woke up the next morning with puddles on the top of my bag, no visible loss of loft and from the waist down, the top of the bag was covered in ice. I remember feeling cozy, but not hot. There is no doubt I let out a lot of water that night. Mostly from exhaling I am sure.

My 7 year olds bag was a 15F REI Zigzag. It kept her toasty with a synthetic base layer she wore that night. She had no dampness on her bag anywhere.

As far as perspiration goes, I have to agree that one perspires a lot through the night, at least based on how hard they worked to get there. The efforts involved may crank up your metabolism causing more sweating than the next guy with a 15 pound pack.

Just my .02c

P.S. I will say based on that experience alone, I would not trust down for more than a weekend at best with the conditions we were in.

Edited by johnatha1 on 09/20/2007 11:30:36 MDT.

mark henley
(flash582) - F
I think Understated on 09/20/2007 11:37:13 MDT Print View

I was in the Pecos wilderness this June when we had a sudden downpour followed by 3 inches of hail, followed by more rain. The humidity went from low to 100% in an hour.

My nice double walled tent, sans vestibule, with two of us trying to stay dry during the night, turned into a condensation trap.

My Down bag was soaked by 11:00 pm and the temperature dropped to the high 30's. I was in trouble and knew it.

I managed to scrape together enough semi-moist wood, that with my emergency Esbit tab and a cotton tee shirt that I had packed for hot temps (cotton tee shirt strips make GREAT tinder for a fire), I managed to get a fire going in spite of the wet ground. It took amost every trick I knew, however, to keep that fire going until the moist wood managed to dry out enough to burn well.

I stood around the fire, with my poncho on and pulled up in such a way that I could dry my bag while keeping the rain off.

My son, who I shared the tent with, had an old north face 20 degree synth bag and even though that synth bag was in the same exact moisture laden tent, he stayed toasty all night long.

I'm rethinking my sleep system and for one thing, the double walled tent is out once and for all. I'll stick with my tarptent, which, by the way, my other son used in the same conditions without a problem in the world, or my tarp and I'm going to carry my Bivy with me even if I'm in a tent.

Rethinking the whole sleep system, I'm considering a more layered approach such as the one that Backpackinglight sells.

I've used a 40 degree ray way quilt with a bivy down to freezing before without much problem. It's surprising how much warmer you sleep in a breathable bivy and how much moisture you keep off your bag.

Brian UL

Locale: New England
Re: I think Understated on 09/20/2007 17:34:42 MDT Print View

I dont know, I have been in tarptents with crazy condensation which wetted my down bag and I was always just fine and my body heat dried it out eventually.
I am suprised by the difference between your down bag and a synthetic in that situation?
As for winter use of down, I am no real winter hiker but I always thought that a vapour barrier was almost mandatory for any extended use in winter conditions regardless of insulation used?
And just too note Im not saying synthetics dont have an edge in wet conditions, just that down is not quite the cotton of insulations some seem to make it out to be.
I also have a Ray-way quilt and really liked it but for the fact that I made it a bit to short!
But my down quilt stuffs too almost half the volume, has at least an inch more of loft, and wieghts a lot less!
Worth the little extra care in most cases in my opinion.

Brian James
(bjamesd) - F

Locale: South Coast of BC
Re: I think Understated on 09/20/2007 17:59:45 MDT Print View

>I have been in tarptents with crazy condensation which wetted my down bag and I was always just fine and my body heat dried it out eventually.

I think that this discussion highlights the source of a lot of the "conceptual disconnect" sometimes experienced when hikers talk about gear+situation.

I had the fortune of learning to camp in the Rockies and Foothills of Alberta. (North of Montana; probably similar climate.) Spectacularly dry is an understatement: anywhere from freezing to -40 was very safely weatherable by our poorly-equipped scout troop wearing cotton clothes and 80's era jackets in rental sleeping bags and worn-out 70's tents.

Then I moved to the West Coast in my 20's and have been slapped silly by the climate on a few occasions. I weigh 185 and I have a high metabolism and suffice it to say that I never *ever* had a problem keeping warm in Alberta. All the way to -40, even as a skinny teenager, I was never cold. (I was famous for wearing shorts to school in -20C/0F weather.)

Out here, to contrast, I can be bundled up and walking in 5 above zero weather, shopping downtown, and get chilled like a vegan 12-year-old girl with an eating disorder. What the??

If you'd asked me when I lived in Alberta, I would have told you "yeah you have to be more careful with down, but if you get it wet it will always eventually dry with body heat." But my perspective was changed by winter rainforest hiking. In Alberta, the aforementioned statement may generally be true. Out here? Maybe 1/2 the time, if you're smart and careful and have some luck on your side. Some Olympics/Cascades hikers will probably back me up on that.

My point is that our perspectives are often shaped by our "home stomping grounds." As Brett said, it comes down to METTT -- and all broad generalizations should be qualified by location, season, and conditions in which they apply.

Ryan Gardner
(splproductions) - F - M

Locale: Salt Lake City, UT
Loft... on 09/20/2007 18:16:37 MDT Print View

Is a bag with 1" of synthtic loft equally warm when compared to a bag with 1" loft of down?

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Loft... on 09/20/2007 19:13:35 MDT Print View

The short answer is "generally not". A high quality 800 fill down bag provides up to 63% more warmth per inch than the AVERAGE synthetic insulated bag. The BEST synthetic insulation on the market provides approximately 30% less insulation per inch than the best 800 fill down bag.

There are a large number of different synthetic insulations. There is also a broad spectrum of down quality and bag construction quality. There can be many exceptions to the general rule.

Brian James
(bjamesd) - F

Locale: South Coast of BC
Re: Loft... on 09/20/2007 20:24:11 MDT Print View

>Is a bag with 1" of synthtic loft equally warm when compared to a bag with 1" loft of down?

Call it heresy, but I don't place any stock in the standard line that loft=warmth.

The two are strongly correlated, *all things being equal*. But all things are *not* equal.

When it comes to sleep systems, the cut, face fabric, and user's sleeping habits combine with loft measurement to determine the total warmth of a system. I've slept in 2.5" loft bags that were warm for me, and 2.5" loft bags that have just about frozen my balls to the ground a few times. (I have one of each hanging in my bedroom.) The difference has to do with draft control (I move a lot) and cut -- *for me*.

I don't think that you can find two otherwise identical bags or garments that have down/synthetic fill as their only differentiator. Thus, comparing loft directly between synthetic and down-filled garments/bags is necessarily comparing apples to oranges. Or something.

Edited by bjamesd on 09/20/2007 20:24:57 MDT.

(RobertM2S) - M

Locale: Lake Tahoe
Re:Re: Loft on 09/21/2007 17:40:11 MDT Print View

Re: " (I have one of each hanging in my bedroom.)" 2.5" loft bags, or balls?

Scott Jones
(Ultimate2) - F
The "real" benefit of synthetics on 09/21/2007 22:37:47 MDT Print View

I think the real benefit of synthetics is that you don't have to be as careful with them. My primaloft sleeping bag is a snap to wash and it dries (on air dry)in a half hour. My Polarguard bags take a while longer to dry, but still easier to wash then down. The benefit is you don't have to worry about tearing a baffle or ruining the down. They are low maintenance. If you spill something on them, you know you can clean it pretty easily and not get stressed out like you would with a down bag. If you accidentally tear your fabric (not that there is much of a chance this could happen, but always remember Murphy's Law, it is much easier to repair a synthtic and you don't have to worry about insulation floating all over the place.

Sure synthetics might insulate better when wet, but I have never been in a situation where the bag got soaked. I guess you would have to maybe worry about it if you have a Black Diamond tent, but otherwise you should be alright.

Sharon Bingham
(lithandriel) - F - MLife

Locale: Southwest
Prevention? on 09/22/2007 23:07:05 MDT Print View

Wow, now you all have me worried. I'm getting ready to make my first sleep system (similar to the Warmlite system, in that it's a "quilt" that is going to zip onto a casing for a downmat), and I've chosen down for the insulation (already purchased, too late to change my mind).

I'm making the shell (both inner and outer) from momentum90, which is said to have a great DWR on it.

I'll be mostly camping in and around New England. While I currently have no plans to use it in winter, I'd like it to be up to the task, and it HAS to work well in the spring and fall. I've got a Rainshadow 2 by Tarptent (good ventilation).

I've only camped in really cold weather once, and condensation was most DEFINITELY an issue. The bag I had at that time was synthetic, and it certainly kept me toasty enough. But I not having had much experience, I had since come to believe the condensation was due to not enough ventilation in the tent (it was a double-walled).

Having researched it (or so I thought), I now understand that condensation also becomes an issue from INSIDE the bag, not just moisture in the tent, and that condensation could still be an issue, even with a well ventilated tent. But then, I also thought that the Warmlite system addressed that as well, by having the entire inner lining of their systems be a vapor barrier...

Therefore I was under the impression that I could keep my down sleep system perfectly functional by having a vapor barrier lining that I can add to the system in the cold, using a DWR shell (so it's breathable, instead of waterproof, therefore not keeping humidity IN, if it DOES get in), and by making sure I have a shelter with little chance of condensation problems (preventing condensed water from dripping onto the OUTSIDE of my DWR-coated bag). I thought I had all my bases covered.

So, my question is, what other down failure stories are out there? And what do you think could have been done differently to avoid the problem (if anything)? Someone earlier asked how a bivy would have helped in some of these situations.

I guess I'm a just a worrier, but you guys really have me all freaked out now about using down. In situations where there's lots of moisture and not much you can do about it, is a VB lining and keeping the outside of the bag dry usually good enough to avoid disaster?

Edited by lithandriel on 09/22/2007 23:13:07 MDT.

Brian James
(bjamesd) - F

Locale: South Coast of BC
Re: Prevention? on 09/23/2007 02:55:45 MDT Print View

I think that your greatest fear should be situations in which your VBL does *not* apply: that is 20F below freezing or less.

If it's cold enough to break out the VBL, it's probably cold enough that the air will hold very little moisture. Also, at that temperature your perspiration can be very well-controlled and your VBL will keep it *out* of your insulation. Any excess humidity will generally create frost on the shelter walls, which may or may not rain down on you depending on the shelter you're employing.

Down will pose more of a danger at *warmer* than about 15 degrees F. At these temperatures, you won't comfortably be able to deploy your VBL but it is of course still quite chilly out. In the absence of VBL, moisture evaporated from your skin will pass into your sleep system -- and probably freeze before leaving.

That said, how many nights do you plan to spend at these warm-but-not-warm-enough temperatures? Will you be able to dry your sleep system at all during the day? Will you be wearing warm clothes inside your quilt that you'll be able to dry during the day?

Points to consider.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Prevention? on 09/23/2007 04:23:47 MDT Print View


> I think that your greatest fear should be situations in which your VBL does *not* apply: that is 20F below freezing or less.
I think you mean 20 F below freezing or WARMER?

Richard Nelridge
(naturephoto1) - M

Locale: Eastern Pennsylvania
Vapor Barrier Clothing on 09/23/2007 05:07:07 MDT Print View

Vapor Barrier Clothing will be more functional, more effective, and more flexible (in your sleep system) than a Vapor Barrier Liner inside of your down sleeping bag. You will be able to have a tighter fit with the micro climate next to your skin. You can wear less clothing and not have the perspiration enter your clothing or your sleeping bag.

You will need to experiment with the amount of clothing that you wear outside of your vapor barrier clothing though.

In my case I have opted for 2 Feathered Friends eVENT outer 800+ down sleeping bags in addition to a Cocoon UL60 Polarguard Delta synthetic fill.

I will need to experiment with the eVENT (waterproof breathable) outer sleeping bags under different conditions. But these bags should by all rights be less prone to the problems of down collapse due to condensation inside of my Six Moons Lunar Solo enhanced tent or my Integral Designs tent. Hopefully in those cases where I want to dry out my clothing while I sleep they will be breathable enough so as to let the moisture through and not collect in the down.


Edited by naturephoto1 on 09/23/2007 05:10:24 MDT.

Michael Davis
(mad777) - F

Locale: South Florida
Re: Prevention? on 09/23/2007 10:54:45 MDT Print View


I have done a fair amount of winter camping in New England and exclusively used high quaility, fill and shell, down for my sleeping system with no adverse results.

Now, let me qualify that statement with two points.

First, I use a tent, not a tarp, so external wetting like spin-drift is not an issue. The tent I use is a Hex3 tee-pee that has top vents and can be set up off the ground/snow all around the perimeter for ventilation. That tent has a high interior volume which I think helps with speading out the humidity (from my breath, etc.) in the micro-climate of the tent. Lastly, the very steep tent walls drastically reduce the amount of drips of condensation that are more of a concern with tents with flatter roofs.

Second, I am only out for 1 to 3 nights, usually not more than 2 nights. A major long trek or thru-hike is an entirely different animal, (unless perhaps you are in a dessert). I do not, and probably never will, have the credentials to address those conditions.

Edited by mad777 on 09/23/2007 10:56:38 MDT.

Sharon Bingham
(lithandriel) - F - MLife

Locale: Southwest
Planned use: Down Sleep system + VB on 09/23/2007 21:45:16 MDT Print View

Yeah, the planned use of my sleep system is going to be mostly for 2-3 day outings (so, 1-2 nights), and not usually (if at all) for flat out winter camping. Though, obviously, I would like it to be useful for longer/colder trips as well.

I'm mostly concerned about all of that unpredictable weather you hear about people encountering up in the mountains - not so much mountains in New England (though it happens here too), but more so about say, in the Rockies or in the Cascades, since I eventually plan to live out that way again.

My Rainshadow 2, well, I haven't had it long enough to test it, but from what I've read, it's good with condensation. There's not much flat space on the roof, and it pitches fairly tautly, with steep enough sides that I don't anticipate dripping to be an issue, especially if I keep a watch on the tautness of the tent when humidity changes...

And not to get too risque, but with regards to VB clothing, and sleeping in it - well, I tend not to like to sleep in anything (clothing gets all tangled up around my legs and arm-pits, etc), and while I can imagine accepting that I may have to sleep in SOME layers in the cold to stay warm enough (or to avoid having to get dressed from a naked state in the morning), I think it would be much harder to adjust to sleeping in VB clothing (as opposed to say, wool or capilene). So I guess my question is, does VB clothing really offer substantial advantages over a VB liner (which wouldn't get all tangled up around me like clothing will)?

Edit: Ok, gave the VB clothing thing more thought. Seems like it DOES offer lots more flexibility: say for example, I have a sleep system that keeps me comfortable down to 0F, without any clothing used, but freak weather drops the temp down to -10F or -20F. If I had VB CLOTHING, I could safely add insulating layers, like a jacket, over my VB clothing, to increase insulation, without being in danger of soaking the extra insulation (since VB is next to my skin). On the other hand, if I have a VB liner, any insulation I need to add could get soaked because the VB liner is now keeping the humidity in with me AND my extra insulation.

Sorry - didn't mean to be slow to catch on there.

Guess that means one less zipper I need to worry about incorporating :-)

That said - is there any VB fabric/clothing that could vague feel like pajamas? Somehow I doubt it...

Edited by lithandriel on 09/23/2007 22:11:28 MDT.

Michael Febbo
(febbom) - F
Overbag on 09/24/2007 00:26:49 MDT Print View

Wow, there are alot of discussion points in this thread...

I just wanted to add that VB clothing may decrease your prespiration from entering the bags insulation, but that is the least of my worries.

The ability to wear all my clothing in the bag, including my parka, is essential below freezing. It is the moisture in baselyers, shells and parka that concern me... even with VB clothing, that will be pushed into the down.

Also, far and away the biggest problem I have below freezing is my breathe condensing/freezing on the shell around the hood and collar of my bag. This soaks right through Quantum (my experience, every time). A bivy helps this sometimes... but not always.

I honestly think the best system is a down bag and a synthetic overbag- protects from external mositure, yet also places the dew point farther from you, hopefully into the synethtic top. I am seriously considering making a quilt for over my WM Antelope for below zero.

Any experience with this kind of thing?