giving cotton another chance

[shannon stoney]

I did a test of how fast various fabrics dry when washed out in a bucket and hung up to drip dry. The results were a bit surprising.

I tested a lightwt woven silk shirt, a cotton woven sarong, nylon pants, a coolmax knit shirt, a power dry synthetic knit top, a cashmere knit top, some cotton pants (not jeans), and a regular cotton t shirt.

The air is very humid here in TN right now and all the clothes were slow to dry. It has been almost 24 hours since I washed them. The only thing that is really dry is the woven silk shirt. The cotton sarong is almost dry, as are the nylon pants. The coolmax knit shirt is still damp, as is the power dry long sleeve knit top. The T shirt and cotton pants are still soaked. The cashmere top is pretty wet too.

OK, so the T shirt and cotton pants don’t make the cut for backpacking or world travel.

The cashmere top may still be wet, but presumably since it is wool, it would still be warm. But it would be more pleasant, I would think, to put on the power dry top on a cold morning. I wonder if merino tops equally slow to dry, compared to synthetic long johns?

I was surprised that the cotton sarong dried almost as quickly as the silk shirt. Both are going in my pack to Peru. I was also surprised that the coolmax knit shirt took so long to dry.

So, if woven cotton dries more quickly than a high-tech fabric like Coolmax knit, why do we say “cotton kills”? (Or maybe WE don’t say that; the manufacturers of synthetic fibers say that.) Maybe the drying speed is not so much the issue as is the fact that cotton is allegedly less warm than synthetic fibers when wet.

As a practical matter, though, when one is camping in areas that are not likely to become very cold, it would seem that being able to wash your clothing and dry it quickly would be more important than its insulating value when wet. That is to say, a normal inexpensive homemade woven cotton shirt might be as good or better than a store bought Coolmax knit top (which must be worn with a bra in public, necessitating another purchase), for certain conditions.

Wonder what y’all think about that. It’s certainly cheaper to buy some inexpensive thin woven cotton fabric and make some shirts, sarongs, and pants than it is to buy or make coolmax or other hightech fabric tops and pants. (The nylon pants seem like a good idea though.)

–shannon

[Michael Schurr]

Good test. Maybe that is why I like cheep Walmart rayon shirts.

[Richard Nelridge]

Don’t forget that your body heat will contribute to the drying of the clothing. You will probably find that the different fabrics will dry differently from your body heat and activity level. Nylons like those used by Rail Riders are known to dry quickly.

Rich

[Neil Bender]

Besides drying time you might want to look at water absorption by weight. Natural fibers, and nylon absorb a greater percentage of their weight in water than most synthetics. To dry that water out with your body heat takes a lot of energy, owing to the latent heat of vaporization of water. Wet garments also conduct heat away much faster.

Your test at higher humidities might be relevant to jungle wear, but in dry mountainous conditions at higher elevations, cotton will take many times longer to dry and will produce much more pronounced evaporative cooling effects. Wet goose down behaves the same way.

I once witnessed a wet hypothermic person being pulled from a wet down bag. The bag was steaming and he felt warm to the touch, but the victim was cold and shivering uncontrollably. All the energy was going into evaporating the moisture laden bag. It’s better to think “wet kills” than “cotton kills”. My motto is ration sweat, not water. I try at all times to dress at a level were perperation doesn’t get trapped in clothing.

In actual use, polyester (and even better polypropylene) dry out with much less of a chilling effect than nylon, cotton, and silk. Wool seems to be an exception, but can still take a long time to dry and wool holds alot of mositure. The weave and the surface treatments of synthetic fibers can greatly effect their moisture absorption and surface “wicking” properties.

For environmental drying in camp I’ve found the single biggest benefit comes from dark colors in the sun. Polypropylene can be made almost dry by wringing and flinging around in the air, but most fabrics made with it have poor texture, drape, and pick up body odors fast.

I like cotton for desert hikes where I stay wet with a water bottle. A wet t-shirt is the only way to hike for long at 110 degrees.

[Scott Downard]

I just ordered one of the RailRiders Long sleeve Speed T’s. I’ve heard good things about cool and dry and that they really last.

[shannon stoney]

Hi Neil, Not sure what you meant about cotton taking longer to dry in the mountains than in the jungle? I would think it would be the opposite. I think the air is pretty dry in the Andes in August. It would seem that that would cause cotton or anything to dry faster. And, at that point, it might be appropriate to worry about getting chilled if you are wearing a wet cotton shirt, as you point out.

I think you are right that it is the wet clothes that kill, not cotton per se, although supposedly wool is still relatively warm when wet.

About avoiding wet clothes: I “test drove” some briefs yesterday that were nylon, thinking that they would be a good substitute for cotton briefs on my trip. Usually when it is hot and humid, my briefs are soaked with sweat at the end of a long walk. But the nylon briefs were dry. I couldn’t figure this out. It didn’t seem as if they were conducting moisture to my pants, because my pants were dry too. What was going on here?

[Adam McFarren]

Shannon,

Just an FYI, but don’t go down to the Andes expecting 100% dry conditions. They are a mountain chain, and can see rain or snow any time of the year. I was in the Cordillera Blanca of Peru last June (also supposed to be part of the dry season) and we had some rain or snow every day we were trekking. Clouds settling in the valleys each evening also made for humid camps.

-adam

[Bruce Warren]

All the ‘cotton kills’ stuff is based on hiking in cold weather. 98% of hiking miles are done in warm weather.

I use 50/50 nylon/cotton clothes with long pants and long sleeve shirts for hot weather hiking. They get wet from my sweat (or pouring water all over me) and the water evaporates and cools the air between the fabric and my skin. Much like a personal ‘evaporative cooler’ as used in desert houses.

When I stop hiking (and sweating), even in humid Texas, my clothes are dry in less than an hour.

Cotton seems to resist getting stinky where synthetics can get real rank real fast. I did a 10 day hike in the same clothes, never washed them. I asked a person back in camp what I smelled like… they said ‘wet grass’.

[shannon stoney]

I have noticed this too about cotton in texas. Even in humid Houston, my clothes dry out amazingly fast, even cotton t shirts. When I do the laundry it is often dry in less than an hour in summer, on the clothesline. Such is not often the case in Tennessee, where they take all day sometimes, and sometimes are not dry after 24 hours.

Lightweight woven cotton shirts dry as fast or faster than coolmax shirts!

[Neil Bender]

In moist air the rate limiting step is evaporation into the air, which is slow because the air can’t take much more moisture. Thus both a cotton and a polyester fabric will dry slowly in still air. A breeze should speed up both as long as you aren’t near 100% humidity. As to your specific case, perhaps you were comparing a bulky poyester garment to a thin cotton garment. The only fair comparison is based on weight, using similar dry fabric weights to get like surface areas. Without that one might find a cotton garment that seems to perform as well as a synthetic one, but the comparison may not be about the fiber as much as other factors.

In dry air, the slower rate limiting step is moisture moving to the surface of the fabric prior to evaporating into the air. Cotton as a fiber holds moisture well through capillary action deep in the fiber. Because of this it holds more water on a weight basis. A pound of cotton can soak up much more water and hold it than a pound of polyester can. Polyester can only hold water on its surface as the fiber itself doesn’t attract water.

So in dry conditions the cotton garment takes longer to move water to the surface where it evaporates almost immediately. The polyester fiber having moisture held mainly by surface tension on the exterior of the fiber does not have the slow step of water moving to the surface to evaporate. This is why I say that polyester will dry faster than cotton in dry conditions, everything else being equal.

Drying clothes on a line won’t predict how the garment will feel if you wear it wet. The extra moisture that a cotton garment holds requires more calories to dry, sucking away body heat.

As for your nylon briefs, nylon isn’t as moisture absorptive as cotton, but is more so than polyester, at least as far as raw fibers go. It’s possible that particuler nylon was treated to “wick” moisture over its surface, or perhaps the weave was such that water vapor passed through. You might find they don’t work as well after many washings if a surface treatment is there to be washed out. But your observation about cotton normally holding onto water and having soaked briefs is expected.

In harsh conditions where I need my clothes to dry from body heat, or in brief moments of sunshine, or in the net pocket of my pack, cotton doesn’t make the grade. Sitting here at my desk in climate controlled comfort I’m happy to stay 100% natural.

[shannon stoney]

Thanks, Neil. That was an interesting post that clarified things considerably.

Today I made some polyester/lycra bike shorts to test drive in the intense heat and humidity this afternoon.

[Robert Ebel]

it is my opinion that the water holding qualities of cotton are good when it is really hot out. I think synthetics can suck your body dry prematurely.

[paul johnson]

this is the first summer i’ve been using synthetic wicking fabrics – top & bottom.

in hot and hot & humid summer weather, i find them cooler (i wear loose fitting T’s – better air circulation???), and definitely less clammy, than the absorbent cotton i’ve worn previously.

in prev. yrs, cotton T-shirts would get so wet that they would be very uncomfortable. they were literally soaked with sweat – even at the lower hem which was not in contact with any skin. the shirts almost looked like they were soaked in water. and then taken out and put on (not quite, but close). you could literally wring the sweat right out of them. cotton boxers were even worse. for as long as i can remember this was one of my least favorite aspects of summer backpacking – sweat soaked cotton in 95 deg heat and 70+% RH. shirt & boxers never seemed to dry out. you just put up w/it & didn’t complain about it. i didn’t know that there was, IMHO, a better way. now, wearing wicking synthetics, i’ve experienced the difference.

also, in the spring when i first started using them, they were great. in the eve, when the temps dropped to mid-to-upper 40’s fr/the 50’s of the day, i would not get as chilled/cold as when wearing cotton since there was less evaporative cooling effect.

[Joshua Mitchell]

To piggy back on neil’s statement. Most sarongs I’ve seen are made out of extremely thin material. Here, the weave / thinness of the material have more to do than the fact that it was cotton.

In warm weather the thinner material will typically keep you cooler. Any meshed material will keep you even cooler still as now you have increased the surface area and decreased the mass of fibers.

[shannon stoney]

What is the difference between regular nylon and poly fabrics at Walmart and higher priced clothes made out of stuff like Coolmax? the manufacturer of Coolmax claims that it is treated in some special way to “increase wicking.” But I wonder: are Coolmax briefs, for example, that much better than $4 nylon briefs from Walmart? Are they worth the extra price?

My favorite cheap Walmart briefs so far are the ones made by Danskin. I don’t know if they have them for men, but the women’s briefs seem great.

[Neil Bender]

Nylon and polyester are similar but different animals. Nylon is hydrophillic (water-loving) and absorbs more moisture than polyester. Nylon is stronger and stretchier as a fiber, but a given weave style can change the way a fabric feels. Polyester holds up to ultraviolet better than nylon, an important consideration for mountaineering tent flys and fixed ropes, but not much of a factor for clothing.

The fineness of the yarn and the density of the weave are hallmarks of better and more expensive fabrics, not usually the type found at bargain fabric stores, but sometimes you get lucky. But for breathable clothing such as a windshirt, a loose nylon can feel more comfortable than a tight weave polyester microfiber, and be lighter. But the poly will shed water better if treated and will dry faster once it does wet out.

Cheaper non-coolmax polyester shirts (Wickers is one brand and Sierra Trading Post carries their seconds at very low prices), seem to work as well as the branded Coolmax stuff in my experience. Nylon in briefs works well because it does absorb some moisture and still breaths well enough.

Generally speaking the refinements of the expensive name brand stuff is hard to justify sometimes. Something that costs 3 times as much might only perform 10% better. If you don’t notice the difference, or if your gear is delivering the performance you need, then that’s a good place to be. I make much of my own gear because I find the commercial stuff over-built and either feature laden, or lacking something I consider critical.

[Linda Alvarez]

What an interesting thread! I’ve actually been curious about this topic. When I’m hiking in the heat, cotton/poly blend “feels” more comfortable than a 100% poly. Polyester shirts just seem hotter for some reason, while a light cotton shirt feels more comfortable. Now, as soon as I add layers and a pack and have to worry about a wet sweaty t-shirt next to my skin after it gets colder, I fall into the poly camp, but on a hot day where I’m just going out to walk for an hour, I tend to grab the lighter cotton t’s. I have been giving thought to reintroducing cotton to my packlist under certain circumstances.

[Robert Ebel]

Someone that aggrees with me! For experienced people cotton has it’s place – just have to know where that is. I remember when I was a young teenager in California I would walk home from church with my sister. Many times I wore this brown synthetic shirt and I hated it! It’s hot down there and the combination of the shirt being brown and synthetic was so uncomfortable. I know now that even if it was brown but cotton I would have been better off. I learned alot from that short sleeve shirt! When I backpack in summer I always keep a cotton shirt along for the hot part of the day or just for variety. I always make sure they are light in color also. Of course I use synthetics also for the right times of the day.

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