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>Have you tried using a pressure cooker?</p>
Just a couple thoughts on your bag. You can buy those Space Age silver heating blankets at the dollar store which would work for the boil bag. Have you tried lining the inside of your padded bag with the foil so it reflects the heat back to the middle? Then you wouldn't have to cut the large hole and lose heat faster. Or if you wanted holes could you use a hole punch and put several smaller holes?<br><br>For reheating the bag I would think that a steamer pot (you know the ones for veggies, 2 part pot, the lower is filled with water and then you put on the upper pot that has holes in the bottom of it). The steam would reheat faster and the bag shouldn't melt touching the bottom. Great write-up!
Thanks for the suggestion on the steamer. I have a rice cooker I could try that with.<br><br>For the padded bag I was using a mylar bag outer bag to reflect the heat back. The hole in the middle was to direct the heat toward my body. If I fully enclosed it then I didn't feel the heat at all.<br><br>My biggest problem these days is the vinyl bag. Vinyl is cheap and available but their seams usually fail after a few months.
<p>I think you would get better heat if you had the vinyl bag in the reflective foil bag and then put that in a cloth bag (denim) of some sort for padding that isn't to thick. The heat can't pass through the padded envelope. Kinda like the rice bags that are used in homes if you know what they are. I do upholstery (part time) and I would think that you could use some of the clear window covering that is used in Jeep soft tops and in tent trailers. It does get a lil stiffer in the cold but with the bag being warm it shouldn't break. It can withstand over 100 deg and well below freezing. The only thing you would have to do is make sure you had a good seal on it. There are different thicknesses you can get, the thicker one would work better for your bags. It can be purchased at any upholstery shop. I get ours from Silver State Supply in SLC if you can't find another. I am going to have to make some of these for work. I have a co worker that has one that he purchased and it is pretty cool. I can't have the &quot;Y&quot; at my work though. I could put an &quot;A&quot; on it though. :) </p><p>Lots of suggestions to consider. For the person that wants to do one with what they have at home your design looks spot on.</p>
Some ideas for warming it:<br>Could you use a kettle, you would have to modify it slightly to make sure you protect the bag from the actual heating element.<br>Cars give off a lot of heat, could you make a safe little compartment under (or even on, if you want) your bonnet so when you've arrive at your cold destination you have a useable warmer.<br>I dont know how long these things take to warm but I imagine the keetle might need more than one go.<br>Also just out of curiousity would a pen clicker set off the reaction?
<p>Pen clickers are generally plastic so they probably wouldn't work.</p>
<p>Your instructable was great. Lots of good info. I started looking up sodium acetate for a totally different reason, but landed here and after a few days made myself a warmer after having some real science fun with my kids. Ran into a few challenges after getting it close, so I thought I would add what I learned. I used baking soda and vinegar to get my SA, so it was helpful to filter it and rinse it with isopropyl alcohol to get rid of particles that were causing it to solidify prematurely. Next, I didn't have a slap bracelet around and wasn't willing to wait for one, so I made a snap disc out of a can lid and a ball pein hammer. It worked but not reliably, so my end fix was just to throw two pennies in the bag and rub them together to start the reaction. Works perfectly. I used an old curtain bag for the vinyl. And our food saver vacuum thing to make the seals (putting a small strip of cardboard in on side for the funnel to fit through then sealing it again after filling). May not last long, but for now it's great fun. Thanks so much for putting this up. </p>
Hey, thanks for the info. I will try the alcohol method for cleaning the next time I try it from scratch.
<p>I love this idea - has anyone tried to 3D print with PLA (flexible) or Silicon and then inject the sodium acetate into it? or better yet, print it like a pillow form with a stopper or resealable tab/screw through which the activator and the liquid could be inserted? The plastic could be printed to be very thin but would probably hold up better than plastic bags or plastic wrap. Just a thought, I know 3D printing with silicon is still fairly limited but when I read everyone's comments I thought it might be a good application for this particular challenge.</p>
<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?

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