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Colored down for cuben items
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Colin Krusor
(ckrusor) - M

Locale: Northwest US
Colored down for cuben items on 02/06/2010 14:06:47 MST Print View

I have been reluctant to make (or commission from Tim) insulated cuben gear like a quilt or a vest because I'm not fond of the bright white color. The colored cuben styles, like the breen, are an improvement but in the lighter products (like the 0.33 oz/yd CT03k.08) the color is very subtle, especially over white down.

I experimented with dyeing the cuben itself, but found that the necessary solvents and swelling agents weaken the film. I tried a dozen different formulas and found that a more chemically gentle dyebath didn't give much of a color.

So, I looked into dyeing the down. Down, like silk, is made of beta-keratin (a protein), and like silk it cannot be boiled (unlike hair and wool, which are alpha-keratin). Mercaptans and ammonia, common in hair dyes, are also likely to damage down. So I obtained five different kinds of dye for protein fibers and set about sacrificing some 800 fill down from thru-hiker.

I used Sebraset/Lanaset azo dye, washfast acid dye, fiber-reactive dye, ammonia-and-mercaptan-free hair dye, and Rit. All of these were dark brown. In each case I added about 2/3 oz (20 grams) of down to a warm dyebath and let it sit for exactly two hours. I then rinsed the down until the water ran clear and dried it in a pillowcase in a tumble dryer on low heat. I also tried leaving the down in a bath of Rit dye overnight. The results are below.

color results

Pictured above are (clockwise starting at the top)fiber reactive, washfast acid, overnight Rit, two-hour Rit, hair dye, and Sebraset. The white sample in the middle is the undyed down. Most of them turned out some shade of pink. The trusty standby, Rit, gave by far the best color. I then decided to try creating a breen color with the Rit (below).

breen, brown, white

I then wanted to see how the dark brown and breen Rit samples looked under a layer of cuben. In the photo below is the brown under 0.33 oz CT03k.08 (left) and breen under 0.68 oz CT1k.08 (right).

brown and green under cuben

The colors turned out well, I think, and it seems to me that almost any hue, including bright reds or blues, is possible. Colored down isn't worth anything if it compromises loft or durability, though.

The procedure for testing down fill power is complex (a 68.4 gram weight moving downward at a precise rate, etc.) and requires a vessel of particular dimensions. But I assume that the nominal fill power of the thru hiker down is accurate, so I just needed to compare it to the colored down. The set-up is shown below.

loft test

I added three grams of dry, fluffed down to a polycarbonate tube 10 cm in diameter and 30 cm in height. I then allowed a 14 gram disk to come to rest on top of the down, and recorded the volume of down in the tube. I performed thirty trials each of the Rit brown, the Rit breen, and the undyed white down. The mean volumes were:

white: 1570.7 cubic cm
brown: 1596.3 cubic cm
breen: 1601.4 cubic cm

The greater loft of the dyed down could be attributable to greater cleanliness due to the post-dyebath rinsing cycles, but it is probably not significant. A t-test for a difference in means showed no statistically significant difference at the 95% confidence level (in case anyone is interested).

I was also concerned that embrittlement or other minor damage from the dye process might not be revealed by the loft test (but might affect the down after many compression cycles). So I examined the down under the microscope. Below are the white, brown, and breen down at 100x:




There is no visible crimping or breakage of barbules. The dyed and undyed down are indistinguishable under the microscope.

I think the colored down under standard cuben gives a cosmetically better result than white down under colored cuben. Deeper and darker colors are possible, more color options are available, and the dyeing process is gentle. Any ideas and feedback are welcome.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Colored down for cuben items on 02/06/2010 14:34:48 MST Print View


Bravo!!!! You created an extremely well researched and documented forum post.

I would like to add to your body of work the fact that colored down would also be visible under low denier nylon. I have a Patagonia Down Sweater vest with a 10 denier nylon shell. It is filled with a combination of grey down and white down and you can clearly see the down colors through the fabric.

Down Vest

Edited by richard295 on 02/06/2010 14:51:06 MST.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Colored down for cuben items on 02/06/2010 14:47:48 MST Print View

Hi Colin

Most excellent! Compliments.


Thom Darrah
(thomdarrah) - MLife

Locale: Southern Oregon
colored down for cuben items on 02/06/2010 14:52:00 MST Print View

Very cool! Who said BPL members/guest's failed to think outside the box. :)

Edited by thomdarrah on 02/06/2010 14:53:16 MST.

Willie Evenstop
(redmonk) - F

Locale: Greater Yellowstone Ecosystem
Colored down for cuben items on 02/06/2010 14:56:13 MST Print View

Nice post !

How warm was the dye solution ?

John Whynot

Locale: Southeast Texas
Re: Colored down for cuben items on 02/06/2010 15:00:34 MST Print View

Very well done -- and the use of a t-test for statistical significance was icing on the cake...

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
coloring down on 02/06/2010 15:13:11 MST Print View

Why don't you see about getting the dyes and chemicals fed to the geese, and then you can get the colored down _in situ_?


David Olsen

Locale: Steptoe Butte
Re: Colored down for cuben items on 02/06/2010 16:16:28 MST Print View

My wife thinks they are beautiful.

She has excellent taste.

Colin Krusor
(ckrusor) - M

Locale: Northwest US
Thanks on 02/06/2010 16:45:34 MST Print View

Thanks for the feedback, everyone.

Cameron, I didn't measure the dyebath temperatures. In all cases I used very warm water (but not too hot to touch) from the tap and I made no effort to monitor the temperature as the bath cooled. The overnight Rit dyebath was still fairly warm in the morning.

Tim Marshall
(MarshLaw303) - MLife

Locale: Minnesota
Re: Colored down for cuben items on 02/08/2010 10:27:56 MST Print View

Wanna test this on some climashield for me too? Discount on Cuben Quilt possible!


Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: Colored down for cuben items on 02/09/2010 10:07:04 MST Print View

Colin- Brilliant, thoughtful, inspired thought process. Not many people would go about the problem from the inside out like that!

My one thought is that I've frequently heard that the longevity of down is in part related to the natural oils on the down. Your images show no physical alteration to the structure of the down, but I wonder if the dye process strips the oils off the down, much as would happen in the dry cleaning process? I have no idea, just thinkin' out loud...

Colin Krusor
(ckrusor) - M

Locale: Northwest US
oils on 02/09/2010 11:33:11 MST Print View


That is a very good point. I'm concerned about this, too. The Sebraset, washfast acid, and fiber reactive dyes are usually used as part of a kit, with separate containers of lye or citric acid, salt, surfactants, etc. I used only the dye powder because I didn't want to strip the oils from the down. The Rit dye, however, already contains salt and surfactants (and who knows what else), and I worry that it may have given a better color because it stripped away the oils.

I can't think of a reliable method to examine the condition of the surface of the down fibers. I'm not sure that microscopy would be the right tool. I may try to test water absorbtion of the dyed and undyed down. I also might try experimentally compressing the down a few hundred times and retesting loft.

Any suggestions?

Morgan Rucks
(rucksmtr) - F
... on 02/12/2010 13:27:16 MST Print View

just hike a thru hike, then you'll have brown down

Juston Taul

Locale: Atlanta, GA
Nice read. on 02/19/2010 15:01:40 MST Print View

Good work Colin. That was very interesting and detailed work. Best thread i've read in a while.

Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: oils on 02/19/2010 15:12:22 MST Print View

My thought, admittedly based on little science, is that the surfactants would strip oil, and that oils left on the down would block at least a degree of dye absorption. I have no idea how you could test it, really. My first thought would be to somehow automate a plunger on a French press and let it cycle a few thousand times...

James D Buch
(rocketman) - F

Locale: Midwest
colored down on 02/20/2010 07:30:14 MST Print View

You might be able to get some sort of help from the International Down and Feather Laboratory.

I'd begin by looking through their site for any descriptions of tests for loft and lifetime. Then I would consider calling them or sending them an email describing that you have been doing research on coloring down and have reached the point where you are interested in possible effects on lifetime or durability of colored down. I wouldn't blurt out that RIT dye was your proprietary secret, just that you are currently regarding the process used as proprietary.

Then, see what you can learn about lifetime tests and/or has anyone done this before because you don't want to just reinvent the slicing of bread.

I think that if they expressed curiosity, it would be great to describe your improvised loft study and particularly the statistical conclusion. Being in the testing business, that information exhcange may prompt a little more disclosure than they would give to "just plain old curious joe".

Nice work!