Instructables
Everybody has seen them, the instant hand warmers sold during the winter months for insane prices. However In this instructable Im going to show you an easy way to make an instant handwarmer with things that you proably have liying around your house!

Its a little odd for me to be posting this in the middle of summer, but in hopes of another stay warm contest I would like to see your feed back to help improve this instructable.

EDIT: BE SAFE
please avoid direct skin contact with the solution! I am by no means a chemist, I do not know how safe this reaction actually is.  I've heard several people say several different things.  Some people claim this produces hydrochloric acid, but I never got burned from touching it.  Whatever is actually happening doesn't matter, please be safe and do not touch the solution or inhale the fumes! Thank you!
EDIT: Published in Popular Science! :D 
http://www.popsci.com/diy/article/2012-02/5-minute-project-hand-warmers


Step 1: Gather the materials

There are only 4 things needed to make the handwarmer, all of them are very easy to aquire, if you dont already have them.
*one large ziploc bag
*one smaller ziploc bag
*some calcium chloride ice melter pellets
*Water

Thats it!


really it is!

Step 2: Fill the large bag with calcium chloride

Simply, fill the larger bag with calcium chloride until there is about 1 1/2 inches of it from the bottom. Try not to overfill the bag because it actually could melt through the bottom.

Step 4: Combine bags

Put the smaller bag full of water into the larger bag full of calcium chloride, squeeze out the excess air, and there you have it a cheap and verry useful instant hand warmer!
 
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Mr Cheeseo4 years ago
How hod does it get and for ow long?
junits15 (author)  Mr Cheeseo4 years ago
The heat output and time is determined by the ammount of CaCl2, simply the mor CaCl2 the more heat and the more time, just becareful not to put too much or you could melt the bag!
What about using a glass snapple bottle with lid? Is the gas toxic? When this stuff is no longer heating, what do you do with it?
junits15 (author)  GramaTuesday1 year ago
You could do that, but that defeats the purpose, the idea is it's something you can stick in your pocket. A glass bottle is almost chemically inert (HF etches glass) but it;s glass, so one slip and now you have a mess of broken glass. Not fun haha
I live in my rv in Washington and it gets so cold here in the winter months. I heat water in a snapple bottle in microwave and set on my lap to warm my hands and legs. My thought was using this idea so I don't have to use microwave.

I have plastic liter bottles and looks like using the baggies that are thin plastic there isn't any chemical reaction that would compromise the integrity of plastic...a liter bottle would work also.
Glass is pretty chemically inert so you should be fine there.
A very fine line that deserves some very not so fine experimentation.






























END TRANDMISSION
So is the gas breathable? If it is, perhaps using plastic water bottles instead of baggies????
junits15 (author)  GramaTuesday1 year ago
true the gas is something you could inhale, but like leaded solder and fireworks, be safe around it, don't tease it and it wont bite you.
no the gas is NOT breathable...that is to say, that if you should breathe it in, it COULD, burn your lungs...I say COULD, not would. it depends on how much of the gas gets into your system.
turbonegro5 years ago
I wouldnt want a needle in my handwarmer
now this is just my personal opinion, so take it as such...

I would not want a needle within a country mile of any homemade hand warmer.
That would be like an accident waiting for a place to happen.
Focker5 years ago
To pop the small bag, just rub the seal and it should slide itself open.
I like your idea...it sounds like the safest way to combine the water with the pellets
junits15 (author)  Focker5 years ago
oh thats a great idea! i be sure to update it!
SIRJAMES091 year ago
this is a cool instructable!!!
I never had a clue that it could be this easy....
TY for sharing Sir.

Toxicology:
Calcium chloride can act as an irritant by desiccating moist skin. Solid calcium chloride dissolves exothermically, and burns can result in the mouth and esophagus if it is ingested. Ingestion of concentrated solutions or solid products may cause gastrointestinal irritation or ulceration.
(copied from: Wikipedia - Calcium Chloride....
http://en.wikipedia.org/wiki/Calcium_chloride)

So in short, IF, if you keep this off your skin, it is no more dangerous than a stuffed Teddy Bear..but if you DO get it on your skin, rinse it off ASAP with plain water & a wee bit of soap. after washing it off, there is no long term hazards.
shannonlove3 years ago
The reaction of Calcium Chloride and water is CaCl2 + H2O--> Ca(HO)2 + 2HCl. Which is calcium hydrate and hydrochloric acid.

I am pretty sure they mix some type of base with the Calcium Chloride to react with the hydrochloric acid to turn it into a common table salt (NaCl) and carbon dioxide (CO2). The CO2 is the gas produced.
Please note, this is not correct chemistry. An acid and a base cannot co-exist in the same solution. The CaCl2 reacts with the water and releases heat...an exothermic reaction. Calcium Chloride pellets can be purchased under the trademark brand Presone Driveway Heat or Qik Joe at hardware stores, home improvement/big box stores and the like during pre-season and winter months.
It's actually fairly common to find dry combinations of acids and bases. The most commonly known would be baking powder which is a combination of sodium bicarbonate (base) with tartaric acid (acid). They do not react until mixed with water. Then they react and produce CO2 used in lea

In this case, however, I was wrong because I neglected that CaCl2 is an ionic compound. When dissolved it goes CaCls-->Ca(2+)aq + 2Cl(1+)aq. The ionic dissolution creates the heat from the energy stored in the bond. 

My chemistry is apparently a bit rusty. Not a lot of call for it in the programming biz.
heathbar645 years ago
I think I remember that regular old rock salt is calcium chloride. Have you tried using it? I never checked what the little Ice melting pellets are made of, but I know they are way more expensive than regular rock salt.
Rock Salt is sodium chloride NaCl2. Calcium chloride is CaCl2. They are two different chemicals. Calcium chloride pellets are exothermic which provides the heat releasing action when exposed to moisture (ice, water, etc.) Rock salt is not exothermic and will not work in this application.
I believe that's SODIUM chloride, friend.
The way I learned it, table salt is sodium chloride and rock salt is calcium chloride. But then, I'm just a hillbilly.
Bert99 Fishpail4 years ago
ur rite it is
junits15 (author)  heathbar645 years ago
I'm not sure about regulat rock salt, and I havent tested it because I dont have any on hand, but when I get some I might give it a shot
Fitwit2 years ago
ZipLoc bags and the like are NOT water-tight. Plan on leaks.
ariearie2 years ago
Don't leave those bags in the car, hoping you could use it when your get onto a frozen car... when it is freezing outside, the water in the inner zip bag will be ice and it will not work..
AnaisM2 years ago
Is there are specific reason why we should squeeze out the excess of air, or it is just to make it more compact and less likely to burst?
nintwala AnaisM2 years ago
its probably so that you can break the inside bag instead of the outside cause the air will cause some cushioning.
junits15 (author)  AnaisM2 years ago
Just so it doesn't break when you open it
NatNoBrains3 years ago
LOL 5 Minute and instant at the same time!
i like the idea, but the chlorine stuff, where can you get that? if you can tell me where to get it, i plan on making it!
junits15 (author)  ducktape.mac3 years ago
its ice melter, get it at like lowes or someplace like that but its not the salt kind of ice melter
is it cheap?
junits15 (author)  ducktape.mac3 years ago
kinda, if you get a little jug
okay, thanks.
beehard443 years ago
finally! i am searching ideas for my MRE warmers (i was able to preserve them) and originally thought about 0000 steel wool ground into filings and vinegar.
kariswg15 years ago
WOW, my wife buys the ready made hand warmers during our cold Michigan winters. I just tried this out and I am going to make some up for her to carry in the car. I will check out thicker bags, because they really get very warm. Thanks again.
pyroal kariswg14 years ago
i live in michigan to and this will help when i go hunting
junits15 (author)  kariswg15 years ago
Glad you like it! Try some glad freezer bags they seem to work very well.
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