Layering question

Personally I like to layer a light fleece layer under puffy insulation.
Like the patagonia cap 4 hoody. 8oz, warm, wicking, breathable, and good insurance for wet weather.
I've drenched my MB thermawrap a few times in wet weather, even under a waterproof shell, (my own sweat I guess?). While it stayed warm-ish…it was pretty uncomfortable.

It depends on the sizing of your thermawrap. If it's sized as a belay piece (ie a little big) you should be ok. The biggest issue is the UL parka has so little down in it to start that it doesn't take much to fully compress it. On a big puffy with a couple inches of loft, losing a quarter inch isn't a hugely noticeable, but on the UL Parka it will be. Still, regardless it will add warmth just not as much as a heavier overall piece or if the down was on the outside so it could loft fully.

A fleece vest would be my first choice. R1/Power Dry or Power Stretch would be great and have all kinds of uses with wind or rain shells or for sleep. A vest will give you good core warmth, but not bind up in the arms. Just a simple and inexpensive 100w fleece tee would add a lot of warmth. I'm assuming you are wearing a long sleeve base layer tuned to suit your needs, like Capilene 1/2/3 or some light merino wool base layer.

As long as it fits properly under it works fine

In fact this offers superior internal and external moisture management

You can even dry off the thin down sweater this way if it is damp

I use down under synth all the time ;)

Hold that MB UL Down Parka up to the sunlight to see how little down is in it.
I would only put a windshirt over it. Anything more would compress the down insulation.

My preference would be to carry a down or synthetic hood, and a vest for under or over the Thermawrap jacket. Your hooded windshirt or hooded rain gear adds some warmth too.

Hi Dennis,

One thing to note: as has been detailed by Richard Nisley a couple of years ago in the forums, down can be compressed to approximately 250% and retained nearly all of it's clo/oz rating. If you're not familiar with Mr. Nisley, search the forums; he's our resident expert on all matters insulation.

@Misfit, this is a myth that I have repeatedly debunked and Nisley himself never claimed. The claim is that compressed down maintains or increases clo/INCH as it compresses. But thickness is also decreased in compression so you lose overall clo/oz.

The discussion is basically limited to whether overstuffing down baffles is a good thing and the conclusion is, generally, that what you lose in clo/oz you make up in down stabilization, reduced coldspots, and resistance to compression from other garments. This goes back to my previous post in this thread where the MB UL is so thin to start with that any compression is a major factor at the point of contact (it won't be universally compressed, especially around the midsection depending on sizing). However a thicker down jacket resists that compression a little better. The suggestion of a down vest is really good because it will suffer only compression at the shoulder but should be allowed to loft well around the torso, and there are no sleeves to be smashed flat. A MB alpine light vest is the same weight as the UL parka but concentrates all the down where it matters, the core. It's also cheaper and probably

Personally I use thin down under synthetic too but I just go in not expecting the down to provide a 1 to 1 boost in warmth because I make that sacrifice for better moisture protection. I don't own a vest but have been seriously considering one to use with a synth outer for those wet near freezing days that drop colder at night.

My first inclination would be to wear the down on the outside of the synthetic, gaining a bit of VBL. With the down under three outer shells, the moisture will get trapped there. With the synthetic under, you have a bit more resistance to compression and some moisture-hating layers. That leaves the down outside where compression isn't an issue and it can vent. If the weather is wet, it isn't all that cold and I would layer the synthetic stuff with my rain shell with the down packed safely away for sub freezing/dry weather or sleep.

But why would I carry both, unless it is a make-do strategy as that is what I own? Sounds to me that both layers are weak for the conditions. You've got 4 shells stacked up there with some light insulation. That seems inefficient, expensive and not very breathable. Better than being cold for make-do, but wrong in so many ways as a layering system end goal.

If you are getting your insulation wet from perspiration, you are over dressed for the activity level, period. I think the reluctance to stop and adjust layers on the trail leads to a lot of misperceptions about layering and clothing systems. It's better to start off a little cool as you will quickly warm up with your back covered with a pack and all the activity. That's a major reason for full zip shells too.

i own and use a MB EXL under a dead bird atom lt

also a EB downlight vest under a cheap old navy poofay, that im actually wearing as i type this

and other various combos …

the amount of compression really depends on the fit of the garments relative to one another … even with the ultra thin EXL and 900 fill down i have never found this to be an issue in normal use …

it also depends on how YOU fit the particular down sweater … and ill fitting one can have compression spots … and as in the BPL test below, some garments were found to have compression built in anyways …

the other thing to consider is that there is a positive effect on insulation from even a windshirt over down … especially those jackets with a sewn through construction like the MB UL … a synth over down sweater would have the same effect

you can see the test and chart here ….

http://www.backpackinglight.com/cgi-bin/backpackinglight/ultralight_3-season_down_jackets_sotm_2010_part_2.html

remember that many of these down sweaters are designed to be used as MID layers … where there will be some compression regardless … whether under a windshirt, another jacket, etc …

the use of a 2-4 oz fill down sweater under a synth is also ideal for moisture management and drying … to put it simply its much easier to dry a thin damp layer than a thicker one …

;)

My first inclination would be to wear the down on the outside of the synthetic, gaining a bit of VBL. With the down under three outer shells, the moisture will get trapped there. With the synthetic under, you have a bit more resistance to compression and some moisture-hating layers. That leaves the down outside where compression isn't an issue and it can vent. If the weather is wet, it isn't all that cold and I would layer the synthetic stuff with my rain shell with the down packed safely away for sub freezing/dry weather or sleep.

no dale …

unless you are wearing an actual VBP or not very breathable rain jacket …

the moisture will still migrate outwards … remember it travels AWAY from the heat source

http://umanitoba.ca/faculties/kinrec/research/media/Cold_Weather_Clothing.pdf

there are TWO sources of moisture

– external … a layered over synth over down will protect from this … spray, rain, snow, etc ….

– internal … from your own body … body heat will push out the moisture to the last layer … in this case the synth … of the down is on the outside then itll end up there … there have been cases on BPL of people sleeping with down over synth and ended up with wet bags ….

the other benefit of course is that your ultrathin down jacket is protected from the outside by a more durable and probably cheaper synth …. a rip in down means fluffy pillow fight, one in synth does matter as much

;)

Understood that the moisture will condense at the dew point, wherever it lands in the "system."

I would assume standing around in camp or on a rest break, with both layers reasonably dry. If you are active and generating a lot of sweat, you're wearing too much anyway. The down would be stashed!

Why someone would take two light puffy layers is beyond me, other than the fact they they already own them. It gets kinds of academic anyway, as I'll bet that anyone who is wearing a puffy and wants a second layer isn't going to peel off the first layer to get them in the "right" order— whatever was in the pack will be the last layer on.

I'm not in the habit of hugging rocks, so damaging the jacket is academic :)

With sleeping bags, the duration of exposure is so much longer that I wouldn't make direct comparisons to wearing a couple jackets for belay.

standing around "camp" … you still have the issue of moisture … especially if you are wearing layers that are damp from sweat/rain from when active

the key with using 2 layers … is that for quick stops you have your synth puffy which is more moisture resistant … you dont need to whole enchilada for a 5-10 min break … you ONLY take out the down from the dry bag in camp mostly, thus once a day

when yr in camp … you put the down under the synth … this allows an instant boost in warmth, which also allows the drying of base layers damp from moisture … the moisture will migrate towards the outmost layer

remember that in nasty conditions, your synth puffy that you use all day for belays/stops will get damp, as will all your layers … if you put all those under the down jacket … all that moisture will end up in the down

even wearing the down under a rain jacket may not help as we all know that the breathability is cr@p when highly active, and the interior will have moisture … a boundary synth layer keeps the down dry

where this becomes impractical is in very cold temps where people use synth as an ACTIVE layer, and the down as a belay jacket … but thats due to the size of the down poofay which wont fit under the synth

for milder > 20F temps it generally works fine

also when sleeping this is superior as it allows you to spread the insulation on both the upper and lower body with 2 pieces … rather than having it all on the upper body, or bringing things like down pants

i have used this system even in the middle of rain storms and it works …

put a hawt nalgene inside and you can even dry the down sweater if it gets damp

moisture management is an absolutely fundamental skill if you use down IMO should you be in wet environments … one of these days youll screw up and get it damp/wet …

;)