In article <
[email protected]>,
"Budstaff" <budstaffdotusegroup@btinternetdotcom> writes:
|> "John Everett"
|> >
|> > Cotton is NOT a wicking fabric. I just went and grabbed a couple of my
|> > wicking shirts, one from REI (a US outdoor store) and one a North Face
|> > brand. Both are 100% polyester.
|> >
|> In my experience the sun protection is more important than whether the
|> fabric is 'wicking' or not. The humidity is _so_ low that the only
|> indication that you've been sweating at all is the crust of salt!
That is partially true, but not entirely. It is CRITICAL that the top
layer is (a) VERY vapour permeable and (b) loose - if you think about
the physics, you will see why! Under a strong sun, you can avoid a
LOT of heat gain by allowing the surface material to get hot (and it
can get 100+ Celcius) and reradiate the heat - this is why all medium
sized savanna mammals have hair.
The other thing that people often miss is that sweat that comes off
as liquid is water wasted. As long as it evaporates, you 'gain the
coolth', and it doesn't matter too much whether it soaks into your
clothing first. That is why people who need to take SERIOUSLY hot
conditions (60 degrees Celcius and up) favour tight short-staple
cotton underwear (to prevent sweat dripping off and let it evaporate)
and loose cotton overclothes.
God alone knows why the Lycra fetishists believe the propaganda that
cotton isn't a wicking fabric - it is THE original wicking fabric!
What are candle wicks made from? More seriously, all of the
traditional practice, pre air conditioning tropical guidelines and
modern military desert clothing favour it or a close imitation. I
have carried a pack, comfortably, at 49 Celcius (shade temperature)
under a hot sun by doing that.
The best synthetic alternatives are NOW probably as good as cotton,
but they weren't even a couple of decades back when that propaganda
campaign started. Most synthetics are a good way to get prickly
heat in humid conditions or when sweating vigorously.
Regards,
Nick Maclaren.