Performance characteristics of nylon and spandex when used as base layers

I've worn a supplex nylon MYOG shirt for years

It has fine fibers so it has a cloth like feel

SPF 30+ sun protection

very breathable

Most supplex has DWR

I don't think it's very wicking. If you put a little water on it it'll bead off, but after a while it soaks in sort of like cotton, but it doesn't absorb very much water and quickly dries off. I think this has to do with the fine fibers.

I own a few nylon travel shirts (Mountain Hardwear "Canyon" shirts) and pants (REI Sahara and REI Adventure). I agree with the above that they are not very moisture absorbent, but I find them comfy enough from hot/humid tropics to temperate climes to cold climes. They also dry quickly.

But to me, the most comfy are my blended 80/20 poly/cotton tees. They feel just like cotton, are quite absorbent, but dry quickly as well.

I've also tried 100% Coolmax and I like them the least. I know they shouldn't, but somehow — to me — they seem to share the clammy feel of cotton when wet — meaning like a wet rag draped on me. They do dry faster than cotton though.

Does anyone have non-anecdotal information? When I've used fibers containing nylon and spandex too, my observations are similar to those that have been expressed. I guess I'm looking for "textbook" information about these fibers.

Excusez moi… but didn't you say "raw observation" helpful"? :)

I might be using inaccurate terminology. By "raw" I was thinking data-oriented. For example, how much water can spandex absorb? 20 percent of its weight, 50 percent of its weight? How does the breathability of nylon compare to polyester? Half as good? I have no idea.

In the last post I didn't mean to discount the anecdotal observations. I'm looking for both.

First you say "raw observations helpful"

Now you want textbook information

Geez!!!

SPF 30+ is non-anecdotal

Just kidding : )

Andrew:

I'm more of the "try it and feel it" school. But if it's hard facts and figures, the school of Richard Nisley is what you want. My head spins and my eyes water whenever I see his charts, but they're right up your alley. :)

You're right, Richard's charts are right up my alley, though they're almost too much for me too sometimes. I just sent him a PM; hopefully he will log on.

Great thread. I have nothing to add but I will be following this with interest.

Andrew,

My raw observations are that close fitting (elastane component) and loose knit polyester base layers work best for me in cool/cold weather use.

A tight-weave white loose-fitting nlyon shirt, with side/back flap venting, (like RR Echo Mesh or MH Canyon Shirt) works best for me in warm/hot weather.

Unlike the aforementioned subjective commentary, the following data table is intended to be an unbiased assessment of the base layer technical trade offs:

In conclusion, the use of nylon and elastane in a base layer is a non-optimal solution for both warm/hot and cool/cold environments. The elastane will create an optimal fit for cool/cold weather wicking. Unfortunately the nylon won't provide the dry boundary layer of air required due to its high regain. In warm/hot environments, forced convection can't effectively cool you because the base layer is against your skin.

Regain will increase as the denier goes up. I provided average figures for the deniers commonly used in UL backpacking (5 – 30).

Richard comes through again…

Two questions (for now):

1- Where does this data come from?

2- Can you define "regain". Is this a measure of how much water a fabric can absorb, as a fraction of its weight? So if you have a 100g of wool, 14g of water vapor can be absorbed?

Andrew,

1. The consolidated information that you requested is not available from any single source that I am aware of. It was a relatively easy topic for me to respond to because I had already posted forum responses to most of the sub-topics in your question. Abrasion resistance was the only new piece of information that wasn't previously discussed in the forums.

WARNING – The following 2007 thread goes into more detail than most people are interested in

See http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=9830&skip_to_post=71012

2. Yup

Hi Richard

Not sure about that figure of 14% for wool. Working in Textile Physics, we normally used a figure of 33% by weight. Yeah, wet wool is HEAVY.

Cheers

One of the interesting commentaries in this thread and the thread linked by Richard is the argument that cotton makes a good base layer in dry, hot conditions (i.e. the desert, in the summer). Is this a widespread and substantiated claim, or is this is personal preference/subjective thing?

I've always wondered why Ex Officio put some cotton in their travel shirts — I figured it was because these shirts were not performance-oriented, but perhaps there's a good performance argument for cotton too.

One of the interesting commentaries in this thread and the thread linked by Richard is the argument that cotton makes a good base layer in dry, hot conditions (i.e. the desert, in the summer). Is this a widespread and substantiated claim, or is this is personal preference/subjective thing?

---

Andy, probably a personal/subjective thing. But my experience is that cotton absorbs all the moisture. Synthetics "pass" some through as vapor. In hot weather, if your shirt is soaking wet, the evaporation actually cools your skin. This is how an evaporative house cooling system works. As the water evaporates, it removes heat from the living space. This is an important concept… air conditioners do not cool air, they remove (or transfer) heat.

No hard facts, Andrew, but I've been wearing 80/20 poly/cotton for years now and I LOVE them! My own experience anyway, they provide the best of both worlds: cotton feel and comfort, less synthetic odor after a few days of wear — and yet, wicking and quick drying. Having worn blended apparels for both hiking and traveling, I don't find them falling short in "technical performance" at all.

Adding to what Nick wrote above, cotton's moisture retention does help to cool the wearer (somewhat) in hot, dry climes. But the same property would work against the wearer in hot, humid climes just as no swamp cooler will work well in the humid tropics.

I chuckle when I see people simplistically categorizing different tools into either one or the other extreme. "Cotton Kills" is one such idiocy. Our tools have almost infinite degrees of suitability, advantages and disadvantages — and it's knowledge/experience that help us fine tune our tools to the different tasks at hand.

Andrew,

We all know reasons NOT to wear cotton. However, in dry & hot conditions it is nice since it breathes so well and feels good next to skin. Also it works great for soaking in a creek and putting it back on to facilitate some evaporative cooling.

As for being substantiated – not sure. But I've experienced this and have read others make the same claim.

Todd

In hot places like Death Valley the NPS highly recommends cotton for breathability and just overall comfort. So I think it's pretty common knowledge.

Eh. Cotton might 'kill' when in the wrong hands and worn in less than ideal scenarios. This reminds me of individuals who complain about down collapse in their bags and garments because they didn't take the proper measures to keep themselves and their gear dry. Cotton is a perfectly acceptable material for much of what I do outdoors in late March through September where I live. Trailrunning 5 days in the week after work under <10% humidity, 95F air temp, and a high desert sun calls for cotton, not spandex or nylon or any other techy garment. Capilene 2 is about the only other exception and occasionally a lightweight merino, but if I can, I reach for a threadbare cotton t-shirt for trail running. Backpacking is a whole different thing for me, I always wear a thin merino shirt or a Capilene 2 next to skin, cotton has yet to be the dedicated baselayer for a backpacking trip. This is my preference more than anything and obviously isn't supported by any science.

I'm no expert or anything but

The numbers given are for "vapor moisture retention"

That doesn't seem very useful. When you're wearing a base layer it's going to get damp from sweat. Then you're into liquid moisture retention which varies with fiber and fabric.

I took my nylon supplex shirt and got it wet, wrung out, and then let it drip for an hour or so:
dry weight – 295 g
wrung out wet – 485 g 64% moisture
dripped for about an hour – 415 g 41% moisture

I compared to a polyester "wicking" top (Terramar Body-Sensors – Thermolator II Shirt):
dry weight – 229 g
wrung out weight – 594 g 159% moisture
dripped for about an hour – 405 g 77% moisture

This is why I prefer supplex – it absorbs a lot less water. And it feels more comfortable when it's damp – maybe because it absorbed less water.

Even though most of the "wicking" base layers are polyester, and supplex is advertised as outer wear.

Maybe Polypropylene is better, but that's less commonly available.

Roger,

I am aware that the Australian based publications refer to wool regains in the 33% – 35% range. I used the ANSI/ASTM D 1909 standard for the values I posted. It lists wool (all forms) at 13.6%.

Does Australian wool have a very large denier (regain goes up with denier) or do you use a regain test other than D 1909? Either way we are in agreement that wool absorbs more water vapor than any other common base layer fiber.

Since I have quite a range of conditions where I live I will try to add to this. In hot and dry conditions cotton or a cotton blend is great because you get some modesty coverage and if the shirt happens to get soaked through it dries pretty fast but looses some sun protection. I have found that poly by itself seems to trap some more heat in and have found wool to be worse above 80F. I wear more of a 50/50 blend because of the stink factor I seem to generate and none of the other options come close for that. I was very comfortable in them this summer in both humid and dry conditions while above 90F and would have been even better if I could have found a thinner version. The hiking nylon shirts are great in that they allow some breathablity in addition to sun and bug protection while trapping a minor amount of heat. I have found that they are not great for wicking. I wouldn't wear the cotton shirts when it drops below 60F because of the chance they could get soaked and start a chilling process.

Jerry,

My first post in this forum thread has a table states that "Liquid Moisture Retention" is positively correlated with the fabric thickness rather than the fiber type. My second post in this forum includes a link to a 2007 forum thread. In that thread I provided the test data used to calculate the correlations.

The techniques to accurately measure the thickness of a textile are direct contact measurements ones, with inductive or mechanical sensors, in contact with the textile surface under a known load. A tester measures the fabric thickness under a pressure of 5×10−4 N/cm2. This tester is made of a micrometer head unit and is directly suspended above a zero deflection top pan-balance. In the absence of this test equipment, eye-ball the relative thicknesses of your shirts before you saturate them. You should be able to see that your Thermolator II shirt fabric is thicker than your Supplex nylon shirt.

Hi Richard

> Does Australian wool have a very large denier
Actually, most of the world's FINE Merino wool comes from Australia. I am talking about wool under 20 microns. And the figure of 33% does not depend particularly on the fibre diameter in my experience.

Yes, I have measured the dynamics of water vapour absorption in single fibres. The gear I built to do that is, as far as I know, the only gear to ever manage to do that successfully.

> ANSI/ASTM D 1909 standard for the values I posted. It lists wool (all forms) at 13.6%.
Hum … did they know what they were doing in 1909???? I have my reservations. That sort of metrology is not all that simple.

Cheers