TLB,
Admittedly I don't know much if anything about tuning JC/Wintress type reeds.
The reeds I installed in most of the calls I've made, have been unaltered, as are ALL reeds coming from a commercial source.
But Bernoulli's principle explains the cause, the venturi created by forcing air at a higher pressure through a tiny slit, then out into the open air at much lower pressure... is a refrigerator pump, in it's crudest form.
Add moisture, and you'll make ice... add more moisture make even more ice.
As others mentioned, there's freeze up, and there's lock up.
I suffer from both.
Each of us "transpires" moisture out with our breath, at different rates, for this reason you can never blame a brand or even a reed type (brass, steel, mylar).
Though for the most part it only relates to enclosed reed calls.
My own list of calls that will not work, due to lock and/or freeze up, is too long to go into here.
I have to regulate how I use some calls, because, in general, higher pressure "wrings" more moisture
from your breath, as does longer notes.
Staccato sounds, short and choppy, mostly driven with a "puff" of the mouth and cheeks, can run for a while.
Whereas a long wailing bleat will lock the best of the best right up, for me.
But, to a large degree, it isn't just the way I use a call, but where the reed is in that call... how far from my mouth... set in wood, metal or plastic... and whether it's a high or low pitched reed... and even how thirsty I am... have a marked effect on how that particular call will "cool" (and heat back up).
In extreme cold, I'll even go to a single reed open reed, because like AWS says freezing when it's not in my mouth can be a problem (freezing the petals, together or apart).
I will "bite onto" a call between series, to keep it in my mouth and warm, as Rainshadow mentions, but I can't always do that, sometimes I need to catch my breath (or warm up my shooting finger, sticking out of my glove).
When I can, I tuck the call inside my jacket, or in my scarf and under my beard.
The colder it is, the denser the air, and the better that air will carry sound. But in cold times, it's usually very quite outside, with everyone with any sense warm indoors.
I rely much more heavily, on the below handcalling volume of my e-caller, at times like that.
Rainshadow,
It's not just because JC/Wintress reeds are tiny... look at the Dan Thompson Pup Squaller, or a two piece closed reed that can be used in the same "tiny open reed" way the squaller type calls can.
Because it's kept warmer than the refrigerant effect can cool it, it will continue to operate.
I believe the closer a truly enclosed reed is, to one's "warmth" (be it your breath or your body), the less it will suffer from the venturi effect, regardless of size.
*The tiny open reed, actually makes a sixth type of call I regularly use.
Krusty
