Have you ever gone to a football game and frozen your butt off?   While at the game you happen to have brought those little charcoal throw away handwarmers.   You pull it out, open it up, and shake the daylights out of it trying to get it to produce some heat.   Normally the amount of heat you get by shaking the bag warms you up more than the little bag ever will.    The last football game I went to was 30 F so I took one of my body warmer along and it produced 5+ hours of heat!  If your looking for a better solution to help keep you warm during those freezing football games (or other cold outdoor activities) then this is the instructable for you. 

Uses I have found for the body warmer.
1.  Cold football games.
2.  Cold campouts.
3.  My wife takes them to bed with her.
4.  Long lasting localized heat for injuries or sore muscles
5.  Cold car rides to and from work
6. ect.

I have quite a few reasons for making this instructable (explained in later steps), but my main reason is I can't find any instructions anywhere else on how to make a sodium acetate hand warmer from beginning to end.  I want others to share my passion and help me come up with ways to make these body warmers better.   Ultimately I feel the best way to get more ideas flowing on the subject is to put an instructable together that described how to make a decent sodium acetate body warmer.

If you would rather watch how to make it than read it, then go to this youtube video.  (Note: I doesn't include instructions on how to make the insulated bag).

Step 1: Motivation For making this instructable

I have a few reasons for making this instructable. 

1.   I think that Sodium Acetate hand warmers are AWESOME and that everyone should have one.  Unfortunately there are quite a few places that show you how to make sodium acetate, but all of them fall short in showing you how to make a decent hand warmer out of the sodium acetate solution.   Those instructions are missing how to make the clicker / activator,  the proper constancy for the solution, and materials that work well for a sturdy durable bag. 

2.   I want to better understand how the clicker / activator works so that maybe I could make a better one.   I have heard vague suggestions on how it works but have not yet as of yet read a good article about how exactly it works.

3.  I want others making these hand warmers and giving me suggestions on how to improve on this design.   For example, I use vinyl for my bags, but vinyl becomes brittle in cold temperatures.   I went camping with scouts in February one year and it was below 0 F.  After we were done using the bags in the morning I was collecting all of the warmers and putting them in my duffel bag.   I happened to throw one of the warmers into the duffel bag and it shattered the plastic on three of the warmers.

4.   Ideas and examples for better accessories.   I have made a few accessories for the hand warmers over the last few years.  One I have included in this instructable is the insulated bag.   I would like a way to keep the insulated bag close to my chest without having to hug it.   I would like a way to easily put the hand warmers into my gloves.

5.  The biggest drawback to sodium acetate hand warmers (ESPECIALLY the large Body Warmers) is how long they take to boil in order to recharge them.   I would like new ideas on how to reheat / recharge the bags.   I have tried heating the bags in 300 degree oil  (that worked until the bag split a seam),  I have tried putting a metal plate in the bag and heating it with an induction cooker.  I had some small success with the cooker, but ultimately it proved difficult and painful (I melted through lots of bags,  rusted out metal plates, and fought with an induction cooker until I gave up).   Another idea I have yet to try is to integrate an internal heating element.
<p>I see a lot of people trying to make their own sodium acetate with less than stellar results. Why would you bother? You can't make it any way near as pure as a chemical company can and purity is absolutely mandatory for this use. Impurities will interfere with the crystallization process. You can buy 4 oz. of 99% pure food grade <a href="http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=sodium%20acetate&_sop=15" rel="nofollow">sodium acetate on eBay </a>for $8.95.</p>
I agree that it is much easier to buy it, though i disagree that it has to be absolutely pure for the reaction to work. The ratio of water to sodium acetate is main factor in how well it works. <br><br>Also I would recommend you buy it in crystal form (trihydrate) so that you arent paying for water that is very easy to add. Also, that is a really crappy price. I saw 2 lbs (32 oz) on ebay for $14.
<p>The more impurities, the greater the chance of them precipitating the reaction. FYI, it is the <a href="http://www.sigmaaldrich.com/catalog/product/sial/s8625?lang=en&region=US" style="font-size: 15.0px;">trihydrate</a> (3 water molecules) form that has 3 water molecules added to the <a href="http://www.sigmaaldrich.com/catalog/product/sial/s2889?lang=en&region=US" style="font-size: 15.0px;">anhydrous</a> (0 water molecules) form, which is the one you want. If you go to the eBay link, you will see that the $14 for 2lbs that you mention is the TRIHYDRATE form. It is probably still cheaper per lb in that form if you want a lot. The water content is around 40% by weight. Both these forms are crystalline forms.</p>
You are right, i meant anhydrous.
Without the preheating, how long do the warmer bags extend the &quot;life&quot; of the heaters?
I don't understand your question. The &quot;life&quot; of the heater is as long as your bag lasts (since it is reusable). Temperature of the bag doesnt affect tge bag's life. Temperature of the bag does affect how long the bag stays warm during a single use.
<p>I am playing around with sodium acetate and would like to make something like this. There are some good ideas here. Thanks.</p>
<p>Have you tried the vacuum sealer bags for preserving food? The bags we use seem to be pretty tough. It definitely holds up in the freezer and I'm pretty sure the material can stand hot temperatures too.</p>
I have used them. They work for a little while. Eventually they stop working because tiny little holes form and cause tge solution to crystalize when cool.<br><br>If you have sodium acetate its worth trying those bags if you have them.
I see. I suppose those aren't engineered to stand up to repeatedly being heated and cooled and squished around.
<p>Have you tried the vacuum sealer bags for preserving food? The bags we use seem to be pretty tough. It definitely holds up in the freezer and I'm pretty sure the material can stand hot temperatures too.</p>
<p>Have you tried the vacuum sealer bags for preserving food? The bags we use seem to be pretty tough. It definitely holds up in the freezer and I'm pretty sure the material can stand hot temperatures too.</p>
<p>Hi again.</p><p>I have made several attempts to make handwarmer bags, but all of them seemed to have problems. Firstly, I did come up with a way so that you don't need to cut off a corner. When you're sealing the bag, simply make sure there's an extra tab of parchment paper on one of the short edges. It needs to be just big enough to accommodate the end of the funnel. </p><p>I have tried both using the oven, and using a hair straightened. The oven seemed to work better, as I didn't need to unstick the vinyl and therefore risk making small holes. </p><p>However, having made homemade solution, my discs <em>have</em> rusted, and every single one has ended up snapping into pieces. I have thought about spray-painting the discs before I put them in, but I figured that the slits would just rust anyway, and that paint would just slow down the disc from being destroyed.</p><p>Any ideas? I would really like to try making several of these without using a heat sealer or buying solution. (Another possible idea for sealing I need to try- A heat gun and wooden board (similar to oven idea.)</p>
<p>One other thought. I have recently started playing with nichrome wire to melt foam. It might be possible to make your own sealer using the wire. Using the right gauge wire and volt input you could cause the wire to heat up to the exact temperature you want.</p><p>http://www.jacobs-online.biz/nichrome/NichromeCalc.html</p>
<p>When I made my first bag of sodium acetate I had the same problem with my clicker. For mine over the process of a year it rusted away. Ever since then I have made the solution by buying sodium acetate pre-made and haven't had this problem. I don't really know what is wrong, but here is my best guess.</p><p>I was talking with my neighbor about the problem (he teaches Chemistry at my local high school) and we both think that there is probably left over vinegar in the solution and that that is what is causing the clicker to rust. Question is how to remove that extra vinegar? I found this video that shows the guy cleaning the sodium acetate crystals using isopropyl alcohol. I would suggest you try that and see if it fixes your rusting clicker problem.</p><p>https://www.youtube.com/watch?v=AedL_NCv1Pw </p>
<p>How about the reusable ice packs, they seem to hold up pretty well and you could put parchment paper between the iron and plastic which would at least protect the iron....I'll say SHOULD protect the iron</p>
<p>Thanks so much for this instructable. I used to have a cheap promotional reusable handwarmer, but eventually it no longer would stay in liquid form. It wasn't until recently that I learned that you could make the solution at home with baking soda and vinegar.</p><p>And closely following the youtube video made by NerdRage, I was able to make two batches (2.5 cups) of sodium acetate trihydrate on the first try (I have another gallon of vinegar solution evaporating in the garage.) Like said by Creak, my solution was an apple-juice color, but I don't care too much, as it still works just as good. I really liked your instructions as they helped the solution become portable and usable with the vinyl and slap-bracelet discs.</p><p>The slap-bracelet was a pain in the butt. Mine had a rubber coating on it, and it took forever to get off. I now have the materials, but I was wondering if you had any tips for sealing the vinyl with a hair straightener.</p><p>I too, am LDS, and mine will most likely have a BYU logo on it. Once it's done, my Biology teacher is letting me bring it in to show to the class. Thanks for the useful winter DIY.</p>
<p>My first hand warmer I made my own sodium acetate with vinegar and baking soda. It also looked like apple juice. It worked great but I did notice that it caused the metal disc to rust whereas buying sodium acetate my disks never rusted.</p><p>For sealing bags -- </p><p>A few years ago I played around with making the vinyl bags by trying to seal them in the oven. I cut out two square pieces of vinyl (both sides of the bag) then I cut out a square piece of paper that was smaller than the vinyl squares. Next I put the first piece of vinyl down, then the paper then the second piece of vinyl. The paper prevents the vinyl in that area from sticking together. I then tried to remove all air bubbles from the edges where vinyl was touching vinyl. Last I heated up the oven to 300 degrees and put the vinyl on a cooking sheet in the oven for a few minutes. (watch it to make sure it doesn't smoke or melt or burn). From there I would cut the corner off the bag and remove the paper. This will make it so you only have to seal one corner with a flat iron.</p><p>When you pull it out of the oven (while it is still really hot) it might be a good idea to press the edges together with something (pizza cutter?) to try and form a better seal.</p><p>If you decide to try this, fill it with water for your first bag and pressure test it to make sure it works. If you try it I would love to know how it goes for you.</p><p>One other idea, you might check with your ward or stake food storage specialists. They often have access to heavy duty sealers used for sealing mylar bags. You might be able to borrow one of them to make your bags.</p>
<p>I first tried sealing the vinyl with a hair straightener, but it was too hard to keep the solution out f the final seam. Otherwise it was watertight. I had some better success by melting the vinyl your way, in the oven. I actually had to heat the oven to 345 degrees to melt it to the point I wanted. I've only made a small one for now, but hope to create a 6 x 4 one before long. However, last night my handwarmer activated accidentally when it was jostled in the car. I wonder if the metal actually clicked, or if you actually need to let it cool undisturbed. I hope there isn't an air leak.</p>
<p>I live in Provo and was wondering if there was anywhere closer I could go to get some sodium acetate? Also, how many pounds or grams do I need to make 2 or 3 small bags? I have been able to find decent prices online, but the shipping is more than the chemical! I would make it myself from vinegar and baking soda but my wife can't stand the smell of it so I will have to get some sodium diacetate premade. </p>
<p>Hi valley chemical up in centerville has it. That is the closest place I know of. You wont need very much if all you want to do is make a couple small bags. 1 or 2 pounds would probably be plenty. If you just want a sodium acetate hand warmer just buy some on ebay or amazon. You wont save a ton of money by making them yourself.</p>
<p>PS I've also heard you can use an alligator clip to create a nucleation site. I haven't confirmed this yet, but another reference said it works! </p>
<p>I began making one before I found this instructable. An unfortunate mistake as I made the sodium acetate from scratch rather than purchasing it. The solution turned the color of apple juice after heating (even though I used white vinegar).</p><p>Regarding a container: I successfully used a small sprite bottle as my hand warmer. Although it is not flexible, I believe it will be very durable. To create a nucleation site I simply added two ball bearings. When shaken they strike each other they create a nucleation site and cause the solute to precipitate. Super easy!</p><p>Problems I experienced: bottle warped when placed in boiling water, lid stripped when tightened hot, layer of crystals formed even when in boiling bath (too much air space?)</p>
<p>Thanks for the tip with the ball bearings. I had no idea that would work.</p><p>As for crystals forming even when in the boiling bath, is the bottle sealed when this is happening? How full is the bottle? I have found you have to have the liquid in a sealed container for it to work. If the bottle is sealed and everything is melted but a fine layer on the surface then I would try taking the bottle out of the water and shaking it up and down. (Be careful when doing this, I don't know if it will cause the lid to pop off). I find I have to do this with my bags to make sure super fine crystals in the corners of the bags are melted. By shaking the bag it helps to heat up all parts of the bag evenly so that absolutely all crystals are melted.</p><p>Thanks for your comments.</p>
Wow it only gets that cold i Utah.
Idk if this has been mentioned , I seen the comment regarding iv bags but what about new bladder bags ? like the kind that hook up to caths . I used to work in healthcare abit and can contest to the new ones being very strong . Don't know how expensive they are but I would assume they are readily available at any local medical store ... and thanks for the great write up :)
I did some quick searching on bladder bags and cant find any very cheap. I did recently get some IV bags and am hoping to try them out. I am not sure how to get a metal disc through the small opening though. <br> <br>If you try a bladder bag I would love to hear how it works out.
Help I can't get past the mushy stage. What am I doing wrong. I didn't do the carbon stage, do you think that is the reason?
I am not sure what you mean by mushy stage or carbon stage. Can you give me more details on what you are trying to do? Are you trying to make sodium acetate from scratch?
Just as a precaution can I warn anyone who is wondering whether to try a microwave to heat one of these - NOT TO TRY IT! All you get is an incredibly expensive Aurora Borealis effect in the cooker for about 10 seconds, then, that's it. No more cooker.<br>It's the metal clicker that has this effect, and boiling is so much safer and economical &hellip;
some microwaves can have metal in them. i can microwave things in a metal bowl with no problems.
One may have better microwave results by turning the power down. My family uses the adjustable level to allow thawing of semi-metallic cans, as well as better cooking for things such as broccoli. Thawing is usually just a level 2 or 3, plenty safe for juice concentrate. 4-6 will generally work for foods that like to sputter and pop, eliminating mess inside the cabinet.<br>I would warn to take breaks and knead the hot spots around.....easier to just boil.
If you want to get the mix more precise, use a thermometer as you're boiling it. The more concentrated the salt is, the higher the boiling point will be. My experimentation hasn't figured out the optimum yet, but if you have, you might take a reading and post it for reference.<br><br><br>What kind of sealers do you use to make the bags? I'm having trouble getting mine to not eventually come loose again.
I haven't used a thermometer, the thin layers of crystals on the surface is usually good enough for me. If you want exact results I think you would have better results using a hydrometer than a thermometer. I haven't tried either though.<br><br>As for the bags, I am using a heavy duty sealer that has a heat element both on top and bottom. Unfortunately even with this I have troubles like you have -- the seams blow out randomly.<br><br>I do have a different idea for making a bag that I have been meaning to post but haven't gotten the time. Basically you use your oven. First cut the vinyl for your bag. Second cut out a piece of thin fabric that is the same dimensions of the bag. With that fabric now cut 1/2 inch off all edges. Then place the fabric between the pieces of vinyl. This should make it so that the vinyl is touching the other piece of vinyl on all edges, but the center of the bag is vinyl fabric vinyl. <br><br>Now heat your oven to 350, place some aluminum foil on a cookie sheet and your bag on the foil. Then place it in the oven for 3 minutes (longer and the vinyl will begin to smoke). Pull it out. While still hot I have gone over the outside edges with a pizza cutter. Once cool, cut off a corner and remove the fabric. You will still have to use a different method to seal the final seam.<br><br>I have only created one bag this way, but so far the seams have held.
I have been wondering if a solvent-based vinyl glue would work well, but I haven't had time to find any.
now...will this get as hot as an mre heater? and if not....can you hack your idea to *get* it that hot?
No, it won't get as hot as that, and no you can't hack it to get it that hot. This isn't really a chemical reaction so much as a phase change reaction. You are getting heat when the chemical changes from liquid to solid. This change occurs around 150 F. So it really can't get any hotter than that.
Very interesting instructable. Has anyone tried the IV bag route? How do you seal it?
this is cool! I mean hot! <br>I'll share what we use around the house. We make a cloth bag or use the sleeve off an old sweatshirt and fill it with about 4 pounds of popcorn. when you microwave this for about 3-5 minutes, it will warm your bed for several hours.
Hey Kevin...how cool...I have been playing with this technology all day yesterday at a Christmas Fair I was working at...in South Jordan at the equestrian center there...anyways...I came home and youtube searched to see if I could make it myself...(they were so expensive to buy) Saw your video..(realized you were a Utah brat too- Cougs! ) ....then I spent five hours trying to find pre-made metal clickers...thinking this would be awesome Christmas Gifts...(My family reunion is this Christmas and over 80 people will be there)....So I get the whole slap braclet deal...but I still would really like to buy a bunch premade...since I have to make almost one hundred for this party....and I am stoked that you said...you found them online for in mass quantities... do you remember where???...because I haven't seen any yet....Thanks! <br>
What about a click style barrette? would those work?
I wish I could remember where I saw them. It was a couple years ago when I was searching for them and I only came across them once. It seems like it was on some Chinese website. I have searched since and never found them again. Sorry.
Have you tried the &quot;food saver bags&quot;? They might work and if you have a food saver unit you can make the size you want and the unit will seal it too. They're made for the freezer.
I've been wondering how to do this for something like 20 years! Thanks for helping to satisfy my curiosity.<br> <br> I have a simple idea for heating--so simple I thought someone would have mentioned it...but I haven't seen it here. My idea is to add some table salt to the water you boil it in to reactivate. This should have a lot of benefits/advantages:<br> <br> &nbsp;1. You've already chosen materials that are compatible with sodium acetate. Most likely, sodium chloride is also perfectly compatible with everything you're using.<br> &nbsp;2. Salt is cheap and about as easily available as a material can get.<br> &nbsp;3. Salt is easy to measure, so it'll be easy to do some trial and error and come up with the ideal ratio of salt to water.<br> &nbsp;4. Salt dissolves easily in hot water.<br> &nbsp;5. Salt is a good preservative. If the salt is concentrated enough, your boiling solution can be re-used many times without turning slimy or green.<br> <br> All you have to do (if I'm right) is to keep using saltier water until the pack reactivates as fast as possible, stopping short of damaging your warmer. The water's boiling point is proportional to the salt concentration. When you find the right ratio, make a note of it, then make up a pot's worth of it. Find a jar or something to store it in between uses. When you're ready to reactivate, pour it back into your pot and boil as usual.<br> <br> Remember that as the water boils, the salt will be left behind, so you will need to add more water to keep your salt concentration from creeping up. Maybe mark the inside of the pot you will use, then when you're done reactivating your hot pack, you can just refill the water to the pre-boiling level with cold tap water. Pour it back into your jar, close the lid and store it.&nbsp;<br> <br> What do you think?
Interesting thought. I will have to give it a try and see how much it raises the boiling point. <br><br> I was also wondering what effect it would have in the solution. In water it lowers the freezing point, I wonder if it would have that effect in sodium acetate solution as well.
&quot;I was also wondering what effect it would have in the solution. In water it lowers the freezing point, I wonder if it would have that effect in sodium acetate solution as well.&quot; <br> <br>I was thinking about this. Adding salt to the SA solution itself would probably interfere with the crystallization process, preventing the packs from working at all. My reasoning is that the Na+ and Cl- ions would disrupt the structure of crystals as they try to form, keeping them from releasing any heat.
I added sugar once to see if I could make the crystals softer in the bag when cool (like it is when it is hot). The solution still crystalized but it took a lot of heat out of the reaction. Ultimately it was still hard when cold. I don't know how salt would change things.
Well let me know when you find out!
Lose the salt ( and chose another team ).<br> <br> This list of &quot;advantages&quot; &amp; &quot;disadvantages&quot;&nbsp;doesn't make any sense.<br> <br> You would have to add 58 grams of salt just to raise the boiling point of a liter of water by one half of a degre Celsius. But the boiling point of water is already 100C / 212F. This is 42C more than enough to melt the stuff.<br> <br> Boiling will simply evaporate your water faster, not transfer heat to the bag faster. The needless use of salt will wear out your metal pans faster, and empty your wallet.<br> <br> Water is cheap &amp; plentiful, why on earth would try to keep the small amount of water you boiled vinyl bags of sodium acetate with? You definitely don't want any animals ( children ) or plants or yourself to have access to such dirty water.<br> <br> Unless you live on a space station or the desert planet of Arakis, it is foolish to be that stingy with water.
You might need lots of salt to make a difference, but so what? That's the real reason to keep the salt water on hand--to save time and the right amount of salt, not to save water. <br> <br>My suggestion was just for the purpose of quicker re-activation. Would it work? I don't know. Nothing wrong with a little trial and error, though. Practice makes perfect.

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