by Todd Walker
Hikers and other outdoorsmen are fond of the ‘cotton kills‘ meme. Search these two words and you’ll wonder how grandpa survived frontier life without polypropylene!
The survival and prepping community should take note. If you’re a lover and wearer of killer cotton, the Bug Out Fashion Police won’t be summoned to whisk you off to polypro prison and re-education camp.
Dirt Road Girl and I repack our 72 hour bags for fall/winter each year. If we ever need to grab and go, we know our kits would contain synthetic, wicking base layers from head to toe. Humidity is high in our state and I sweat a lot with a 30 pound pack strapped to my back. Synthetic material against my skin does a great job at wicking moisture to outer clothing layers.
Do we pack killer cotton in our winter kits? Yes. It has its place and uses.
Killer cotton is not lethal. Choosing the wrong clothing for your situation and environment kills!
So how did this natural, comfy fiber get such a bad rap?
The Science of Staying Warm
Cotton gained the label ‘killer’ by distance hikers for its lack of capillary (wicking) action. To explain, I’ll slip on my lab coat and grab some chalk for a science lesson. I’ll do my best to keep this accessible to our non-geek readers.
Before we begin, here’s your 3 key vocabulary terms for this lesson:
- Conduction – is the transfer of heat when ‘hot’ molecules collide with neighboring cold molecules. Only heat can be conducted because cold is the absence of heat. Ex: I discovered early on that heat travels from the hot end of Mama’s cast iron skillet to the cold handle.
- Insulator – materials that are poor conductors of heat. Air, cloth, wood, and water are poor conductors but make great insulators.
- Heat transfer – thermal energy (heat) can be transferred via conduction, convection, and radiation.
What cotton holds against your skin
When dry, cotton fibers create air pockets to insulate your body. Air is an awesome insulator if it’s trapped in an area. However, cotton earns ‘killer’ status when wet.
Cotton is a stingy absorber of moisture. Once saturated, it holds moisture better than polyester. When you step out of the shower, do you grab a cotton towel or synthetic one? Cotton holds on to what it absorbs.
Cotton soaks up moisture but does a lousy job of moving it away from your skin to outer layers of clothing. Your 100% cotton union suit looses its insulation value when the air pockets in the fiber fill with moisture from perspiration or water. The 50/50 cotton blends only prolong the process a bit. Either of these choices will leave you wet and cold!
The problem with being outside is Mother Nature’s mood swings. She seems to invent ways to make you shiver. If these conditions continue, hypothermia happens without self-directed action to reverse the drop in your body’s core temperature – even when it’s not freezing out.
So to be prepared, plan for the unpredictable.
Layers of Redundancy
Since humans aren’t feathered or fury (up for debate in some cases), the layered clothing strategy creates warm air pockets to slow the heat transfer from your 98.6 degree body to the external frigid temperatures. You’ve seen pictures of Sherpas standing on the top of Mt. Everest wearing a down-filled jacket. It’s not the feathers that insulate, it’s the air space created by the down trapped by the jacket shell.
Remember that heat transfer takes place from hot to cold – not the other way around.
Nature is constantly trying to create equilibrium. Thermal energy (heat) and humidity under your clothing seeks a path to colder, less humid conditions outside your body.
The first step in creating and maintaining that warm pocket of insulating air around your body is to stay dry. Due to its capillary action, I prefer polyester as a base layer against my skin.
On top of that, when conditions are cold but not wet, I wear a long sleeve cotton shirt with a wool sweater. When it’s likely that I’ll be in wet/cold conditions, or some Doing the Stuff training with my B.O.B., I skip the cotton and go with a light merino wool or wool synthetic layer.
Frugal Tip: Never pay full price for expensive wool sweaters. Shop your local thrift stores and stock up on $5 merino wool. Ugly colors won’t matter when you need to stay warm and dry!
Some lovable wool facts:
- Wool fiber absorbs up to 36% of its weight and gradually releases moisture through evaporation.
- Wool has natural antibacterial properties that allow you wear it multiply days without stinking up camp. Not so with synthetics.
- Wool wicks moisture, not as well as synthetics, but better than cotton.
- Wool releases small amounts of heat as it absorbs moisture.
- Wool contains thousands of natural air-trapping pockets for breathable insulation. Just ask any sheep.
Now to add ‘skin’ to your outfit. The outer shell or skin can be anything that repels water. In a pinch, a contractor garbage bag will work to keep you warm and dry. Gore-Tex is pricey. You can pick up USGI poncho cheaply online or at military surplus stores. A poncho in your kit gives you options other than rain protection.
SmartPreppers are prepared for both wet and cold conditions! Does Killer Cotton have a place in your winter bug out ensemble? You bet! Here’s my top 5 reasons pack cotton.
Uses for 100% Killer Cotton
- 600 count bed sheets – just kidding. Wearing cotton inside your sleeping bag makes sense, though.
- Bandanas for making char cloth and many other uses
- Emergency TP. Ever tried cleaning your bottom in the wilderness with polypro?
- Sitting too close to the campfire dressed in synthetic material is not a good idea. Melted polypro on your skin will ruin your day! A flying ember on your flannel/wool shirt won’t melt.
- First aid – cotton and duct tape can be used as a makeshift bandage.
Our ancestors made it through extreme conditions without modern synthetic clothing. Would they have worn polypro underwear and base layers while forging the frontier? Probably.
Should you? Do you? Let us know your strategy and ideas in the comments. Stay safe and warm out there!
Keep Doing the Stuff!
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