Primus "heating pads"?

[OldStormcrow]

I was wondering if any of you were familiar with the heating pads that Primus used to make for their canister stoves. They were clear things that looked kinda like a breast implant with some sort of liquid and a metalic disk inside. When you flexed the disk inside the pouch there was some sort of chemical reaction and the liquid would crystalize as it got fairly hot. I can only guess that these were intended to be placed under the gas canister to make it work in very cold weather, but I used to carry one inside my storm coat for emergencies. I kept it in one of those flat plastic containers that electrical tape comes in to avoid accidentally activating it while hiking. In really extreme weather I would flex the disk and drop it in my left shirt pocket, thus creating a nice warm thing inside my coat for the next four hours or so. They could be "re-liquidfy-ed" by boiling them for about 10-15 minutes....a rather wasteful use of fuel, but nice to have in an emergency. I used mine for a few years before it finally gave out and now I can't find them anywhere. They used to be about $4.50 and I gave a few of them as stocking-stuffers to my hiking buddies at Christmas.

[peakbagger]

Here is a similiar product at REI. http://www.rei.com/product/608751

Just search for sodium acetate as that is the active ingredient.

[berninbush]

I'm curious, do those get hot enough to warm up a meal in a pinch? Not boil water necessarily, just get your food warm if you don't want to fire up a stove.

[partinj]

You can get heating pad for your sleeping and hands and feets at kmart or walmar
cheap to. Found new use for them to help heat of my canister for my snow peak stove up in the cold weather they really good had no trouble down to 0deg. petty good for a canister stove.Boil water in a cover pot in 3 1/2 min.

[peakbagger]

My experience is that they wouldnt work well to heat up a meal. They get warm but not hot (although there is usually a standard warning about people with circulation issues not to use them).

[mudhead]

http://www.howstuffworks.com/question290.htm

Cool explanation of that heat pad.

Anyone ever seen them at EMS or Beans?

[Froggy]

They've been around for a while. I used to use them once in a while until I decided that the liklihood of them self-triggering was too high. When I wanted to use them they'd have been through a cycle and were ready for resetting.

Also, they are one-use until boiling, and just as heavy after use as before.

[mudhead]

I tried some of those hand/foot warmers, air activated jobs. Pretty limited.

I could use a couple of these fancy jobs in the truck. Winter kit. I would want to eyeball them tho, just me.

[Manwich]

Dicks or Sports Authority used to sell a "Hiking Kit in a Nalgene" thing... In it were two of the Sodium Acetate Filled Discs in the Plastic Baggy, Those were literally the best heating pads I ever used. One of them actually got relatively hot...

As for cooking with them... I doubt it'd make anything cold warm enough to be palatable.

[OldStormcrow]

Thanks Peakbagger,
That thing from REI is exactly like the ones that Primus used to make, except Primus' were round. I never used them for heating a fuel tank. I just kept one inside my storm coat for winter emergencies. The fact that you have to boil them for at least 10 minutes is enough to keep me from wussing out and using it on a whim....and the plastic tape case that I mentioned in my original post keeps it from being activated accidentally. I'll check out the new REI in NC for these.