Introduction: The 5 Minute Instant Hand Warmer!

Picture of The 5 Minute Instant Hand Warmer!

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.

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

Step 1: Gather the Materials

Picture of 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

Thats it!

really it is!

Step 2: Fill the Large Bag With Calcium Chloride

Picture of 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 3: Fill the Smaller Bag With Water

Picture of Fill the Smaller Bag With Water

Take the smaller bag and fill it about halfway with water, make sure to squeeze out any excess air as this bag will have to be burst in order to activate the hand warmer. Make sure the bag is sealed well to prevent the warmer from activating prematurely.

Step 4: Combine Bags

Picture of 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!

Step 5: Instructions for Use.

Picture of Instructions for Use.

The hand warmer is now prepped and ready to be activated, in order to activate the hand warmer, squeeze the smaller bag until it breaks, when the water combines with the calcium chloride it it causes a chemical reaction. A byproduct of this reaction is heat and some gas (I don't know what kind)

*keep all the pellets at the bottom
*put the water bag in with the seal facing down towards the pellets
*seal the bags verry well, you could even glue them shut for a better seal

Tell me what you think!
*leave a comment! PM me!

EDIT: 8/7/09 Fockers sugested an easier way to pop the inner bag without breaking the outer bag, quote: To pop the small bag, just rub the seal and it should slide itself open


Jsoa (author)2017-08-30

Which type of hand warmers do you recommend and why? Do you recommend
disposable hand warmers or hand warmers that are filled with lighter
fluid? The latter type is for example from the brand Zippo.

Are handwarmers with liquid fuel hotter or cheaper in use than disposable handwarmers?

And how safe are they?

Check here

and advice to me

1315036647 (author)2017-02-13

I need to find this info. for a project im doing

-the balanced chemical reaction equation that you are using in your design

-the amount of heat given off by the reaction in joules per gram of substance with a cited source
-the specific heat of the human body with a cited source
-how much substance you have decided to use in grams
-a q=mc∆T equation with numbers showing how much the temperature of a human hand would change when given the amount of heat your reaction will produce.

junits15 (author)13150366472017-06-21

Sounds like great stuff for you to find through experimentation and scientific data collection! Its a simple and safe thing to play with so it should be easy to test.

vincenther26 (author)2017-02-15

that was a burst of calcium

jtackkett (author)2016-12-25

There is some incorrect information that has been mentioned in the comments. Calcium chloride and water do not react to form hydrochloric acid. If it did, DOTs (departments of transportations) would not use as pre-treatment on roads before ice and snow storms.

Calcium chloride dissociates with water. The equation would be:

CaCl2 + H2O -> Ca(2+) + 2Cl(-) + H2O

There is no HCl produced.

vincenther26 (author)jtackkett2017-02-15

it's correct to me

someone666 (author)2016-11-09

im in my science class do these hand warmers stay warm long please respond soon as i need the answer soon

jtackkett (author)someone6662016-12-25

The reaction should last 20-30 minutes.

GladerGirl188 (author)2016-10-19

I'm trying this out for a science experiment in my science class, do you know the measurement in grams for the 1 1/2 inches of calcium chloride in the plastic bag?

destiny03 (author)2016-04-15


destiny03 (author)2016-04-15


destiny03 (author)2016-03-22

were can i get calcium chloride ice melter pellets??????

junits15 (author)destiny032016-03-28

hardware store

charlia wright (author)2015-02-28

beehard44 (author)2010-11-18

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.

jasonlfarm (author)beehard442014-12-24

never heard of this. does it work good?

Mr Cheeseo (author)2009-12-01

How hod does it get and for ow long?

junits15 (author)Mr Cheeseo2009-12-03

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!

GramaTuesday (author)junits152013-10-07

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)GramaTuesday2013-10-08

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

GramaTuesday (author)junits152013-10-08

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.

Mr Cheeseo (author)GramaTuesday2013-10-07

Glass is pretty chemically inert so you should be fine there.

Mr Cheeseo (author)junits152009-12-03

A very fine line that deserves some very not so fine experimentation.


GramaTuesday (author)2013-10-06

So is the gas breathable? If it is, perhaps using plastic water bottles instead of baggies????

junits15 (author)GramaTuesday2013-10-08

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.

SIRJAMES09 (author)GramaTuesday2013-10-08

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.

turbonegro (author)2009-08-07

I wouldnt want a needle in my handwarmer

SIRJAMES09 (author)turbonegro2013-10-08

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.

Focker (author)2009-08-07

To pop the small bag, just rub the seal and it should slide itself open.

SIRJAMES09 (author)Focker2013-10-08

I like your sounds like the safest way to combine the water with the pellets

junits15 (author)Focker2009-08-07

oh thats a great idea! i be sure to update it!

SIRJAMES09 (author)2013-10-08

this is a cool instructable!!!
I never had a clue that it could be this easy....
TY for sharing Sir.

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....

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.

shannonlove (author)2011-04-22

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.

Know_CaCl2 (author)shannonlove2012-07-18

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 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.

shannonlove (author)Know_CaCl22012-07-18

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.

heathbar64 (author)2009-10-04

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.

Know_CaCl2 (author)heathbar642012-07-18

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.

Fishpail (author)heathbar642009-11-29

I believe that's SODIUM chloride, friend.

heathbar64 (author)Fishpail2010-07-02

The way I learned it, table salt is sodium chloride and rock salt is calcium chloride. But then, I'm just a hillbilly.

Bert99 (author)Fishpail2010-07-02

ur rite it is

junits15 (author)heathbar642009-10-05

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

Fitwit (author)2012-02-26

ZipLoc bags and the like are NOT water-tight. Plan on leaks.

ariearie (author)2012-02-25

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..

AnaisM (author)2011-11-04

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 (author)AnaisM2012-02-24

its probably so that you can break the inside bag instead of the outside cause the air will cause some cushioning.

junits15 (author)AnaisM2012-02-20

Just so it doesn't break when you open it

NatNoBrains (author)2010-12-17

LOL 5 Minute and instant at the same time!

ducktape.mac (author)2010-12-03

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.mac2010-12-04

its ice melter, get it at like lowes or someplace like that but its not the salt kind of ice melter

ducktape.mac (author)junits152010-12-04

is it cheap?

About This Instructable



Bio: I'm a university student from the good ol' USA! I'm studying Electrical Engineering and loving every second of it! I've always been ... More »
More by junits15:Make your own "audiophile" quality speaker cables!Make a water block out of a heatsink for less than $20!The 5 minute instant hand warmer!
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