I’ve tried many kinds of handwarmer during my 13.5 years doing SOTA. Some are definitely better than others. But none are anything like as effective or convenient as simply putting my big gloves back on for a few minutes.
Mere insulation can only lead to an increase in temperature if there is a heat source. If you have the kind of blood circulation that seems to do a U-turn at the wrists and ankles, gloves are less effective than you might wish.
Same here! That’s one of the reasons I like walking poles - they give your arms and hands a work out as you walk away from the summit, and get the circulation going again. Not much use during the activation, though (in that regard)
A couple of other suggestions from someone in the same boat (who also likes to fly fish - try dealing with COLD & WET hands!) in addition to handwarmers
I got into the habit of taking a baby aspirin before going out. No proof this works, but I figure thinner blood can only help get to the extremities.
Purchase a pair of ‘powerstretch liner gloves’. While they don’t offer the insulation of your regular gloves, they are thin enough to allow good dexterity while keeping the wind and chill off. Again, they are a supplement to regular gloves in the bitter cold, but can often be more than enough in 4C+ weather.
Who needs to go out activating to get cold fingers that go off into shut down mode? My Raynaud’s needs little to set it off - a cold steering wheel is a typical prime mover which will have my fingers losing their colour within seconds. The problem when I am out on the hills is that I have usually forgotten to pack the hand warmers so have to resort hot breath to keep some circulation going. Thank goodness I use a straight key!
BTW, I use chemical type hand warmers as I just can’t get my head around the type with a flame… knowing my good fortune (not), I’d probably have a red hot activation if I used one of those.
I can only comment on the Zippo at the moment.
Generally I fill and light before I leave home. If going to GW/SW, it will be the best part of 3 to 4 hours before I’m on a summit. With about 15 ml of lighter fuel, they will still be hot 12 hours later.
Initially when I first got them, I took the fuel along and filled and lit them in the car before setting off.
This was to save money (yes us northerners know a thing or two - poundshop fuel is 1p/ml), but I found I just used the same amount of fuel and it’s easier to fill and ignite in the comfort of your kitchen.
Not sure about filling before hand and subsequent rate of evaporation.
I’m doing a timed experiment now. I’ve put exactly 5ml in one of the new warmers. It’s now stored in a zip lock plastic bag. I’ll fill the other one with the same amount of fuel in the morning , light both together and see how long they last.
Results later tomorrow…
Both handwarmers were fueled with 5 ml of Poundland lighter fuel (other makes are available).
Unit A was filled last night at approx 2100z and placed in a ziplock bag.
Unit B received its 5ml this morning, 5 minutes prior to lighting it and its partner.
Unit A gave up the ghost after 3 hours.
Unit B expired after 2:55 mins.
The conclusion - fill up the night before and keep in a plastic bag
I expect, in truth, it makes no difference. Obviously, if the unit had not been stored in an airtight enclosure, evaporation would have been an issue, but I wouldn’t recommend storing like so, as everything will reek of lighter fuel.
You can also extrapolate that consumption is about 1ml per 36 minutes, or 1.7ml/hour.
I stuck my temperature probe inside the pouch with the following result.
It was 47C when I got back into the car today, that’s what the LED display indicated so no need for hand warmers over here. Outside got to 39 C today, no wonder I was tired when I got back to the car and tomorrow is forecast for over 40 C .
I am using this dc-to-dc converter from time to time to warm my hands (no joke). I use a 4S 5100 mAh LiPo battery, which will charge up to 16.8V. My Elecraft will shut off if power detected is more than 15V. So using this handy (pun intended) little unit, which warms up a bit, as the heat sinks on each regulator start doing some work. It’s not that much heat, especially if running at lower watt output, but it works for me.
OK, if I was in a colder area, with blowing wind and lots of wet weather, then I’d be looking for something else.