synthetic vs. treated down….

[SherpaWill]

I've been reading/hearing a lot about treated down sleeping bags lately. I'm going to be replacing my 22 year old Coleman 3 season bag this year and I've been seeing the treated down bags everywhere. I was going to get a TNF Cat's Meow or something equivalent that's synthetic, but would consider treated down if it can stay dry. My primary use will be tent camping in The Whites, with the occasional hut/cabin stay. I'm really skeptical of the down holding up for multiple wet days in a tent. Does anyone have any experience with the new treated down? Thanks.

 

[Guthook]

I've been reading/hearing a lot about treated down sleeping bags lately. I'm going to be replacing my 22 year old Coleman 3 season bag this year and I've been seeing the treated down bags everywhere. I was going to get a TNF Cat's Meow or something equivalent that's synthetic, but would consider treated down if it can stay dry. My primary use will be tent camping in The Whites, with the occasional hut/cabin stay. I'm really skeptical of the down holding up for multiple wet days in a tent. Does anyone have any experience with the new treated down? Thanks.

I don't have first hand experience with treated down, but I do have extensive experience using plain down for long periods in very wet weather, so make of this what you will. I find the marketing claims of synthetic vs down wetting out to be pretty overblown in general— I've gone through days of downpours with my only insulation being down, and I've gone through plenty of nights in drenched synthetic sleeping bags. Soaking your sleeping bag is something that you can avoid with some simple precautions, and it's something that will suck regardless of what kind of insulation you have. The last time I slept in a wet sleeping bag was when I was young and stupid (now I'm just stupid, but more cautious). I have learned my lesson since then-- it's better to keep your things dry than to assume your gear will function fine when drenched.

The more important points of synthetic vs down for me are price (higher for down), longevity (also higher for down), weight (less for down), and quality of craftsmanship (type of insulation is irrelevant here). If treated down makes the wetting issue less relevant, that just puts the focus more on other factors that I think are more important anyway.

 

[Chip]

I'll stick my neck out, respond and say *Read My Disclosure after this post:

I am not a scientist. I have been using down products for winter camping for just about 40 years. I too have no complaints.

"DriDown™ - What it is
Simply put, DriDown™ represents the evolution of down insulation. Regular down is treated with a molecular level polymer to create a hydrophobic finish on each individual down plume.
This finish allows DriDown™ to stay dry longer, loft better, and dry faster than untreated down, keeping you warmer in any environment."

Down, itself, is not what provides warmth: it's the spaces in between. The "molecular level polymer to create a hydrophobic finish on each individual down plume" wouldn't do much, IMHO,
unless it somehow also evacuates the spaces in between the plumes. There's plenty of low grade feathers out there. This sounds like an attempt to get some of it used.

 

[DougPaul]

Down, itself, is not what provides warmth: it's the spaces in between. The "molecular level polymer to create a hydrophobic finish on each individual down plume" wouldn't do much, IMHO, unless it somehow also evacuates the spaces in between the plumes. There's plenty of low grade feathers out there. This sounds like an attempt to get some of it used.

Down absorbs water and wet down clumps eliminating the airspaces. Down is hydrophilic so clumped down will also retain the water. Presumably the hydrophobic coating reduces the amount of water that gets absorbed into the down plumes and repels the water from the spaces, reducing the clumping which increases the air spaces and insulation.

There may be a certain amount of similarity to wool. Wool naturally consists of a hydrophobic coating over a hydrophilic core. Wet wool fibers also retain their resiliency and retain their cushioning and much of their insulation.

Doug

 

[Guthook]

Down absorbs water and wet down clumps eliminating the airspaces. Down is hydrophilic so clumped down will also retain the water. Presumably the hydrophobic coating reduces the amount of water that gets absorbed into the down plumes and repels the water from the spaces, reducing the clumping which increases the air spaces and insulation. There may be a certain amount of similarity to wool. Wool naturally consists of a hydrophobic coating over a hydrophilic core. Wet wool fibers also retain their resiliency and retain their cushioning and much of their insulation. Doug

While very true that wool and synthetic and treated down retain their insulating values when wet, the part that the marketing departments always leave out is that insulation isn't the only part of the equation of keeping you warm. Insulation protects from radiant heat loss, but being wet will suck heat out of you just as fast as being exposed to cold air.

When dry down first came out, I saw a hilarious review on trailspace.com where the reviewer tried sleeping out in his new treated down sleeping bag without a tent in cold rain, and while the loft of the bag remained intact, he ended up going inside after a few hours of freezing in his soaked sleeping bag. He realized how dumb the idea was after the fact, but it made for fun reading.

 

[Chip]

Presumably the hydrophobic coating reduces the amount of water that gets absorbed into the down plumes and repels the water from the spaces, reducing the clumping which increases the air spaces and insulation.

Doug

So yeah, that's the assumption right ? Doesn't it seem relatively unlikely that treated down would have the "energy" to displace water for air ? On a scale that would preserve insulation properties ?
(I'm not arguing. I have no idea. Just talking it through.)

 

[DougPaul]

While very true that wool and synthetic and treated down retain their insulating values when wet, the part that the marketing departments always leave out is that insulation isn't the only part of the equation of keeping you warm. Insulation protects from radiant heat loss, but being wet will suck heat out of you just as fast as being exposed to cold air.

I have seen the figure that wet wool retains ~40% of its dry insulation.

Beginners in white water boating who don't have a wet-suit or a dry-suit sometimes wear raingear over wool. The raingear protects against wind and evaporation and the wool provides the insulation.

Doug

 

[DougPaul]

So yeah, that's the assumption right ? Doesn't it seem relatively unlikely that treated down would have the "energy" to displace water for air ? On a scale that would preserve insulation properties ?
(I'm not arguing. I have no idea. Just talking it through.)

Think of a waxy (hydrophobic) coating on the down. The water will be repelled by the waxy coating.

The traditional oilskins (waterproof garments) worn by sailors were made from canvas sailcloth (ie cotton) coated with linseed oil. Another hydrophilic material waterproofed by a hydrophobic coating/impregnation...

I presume the difficulty with coated down is finding an adequately hydrophobic coating that does not reduce the loft. (The insulation value of the down is proportional to the loft (thickness).)

Doug