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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).
http://www.youtube.com/watch?v=SNF2DO6EXcw
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).
http://www.youtube.com/watch?v=SNF2DO6EXcw
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Signing UpStep 1Motivation 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.
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.
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It's the metal clicker that has this effect, and boiling is so much safer and economical …
I would warn to take breaks and knead the hot spots around.....easier to just boil.
What kind of sealers do you use to make the bags? I'm having trouble getting mine to not eventually come loose again.
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.
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.
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.
I have only created one bag this way, but so far the seams have held.
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.
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:
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.
2. Salt is cheap and about as easily available as a material can get.
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.
4. Salt dissolves easily in hot water.
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.
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.
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.
What do you think?
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.
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.
This list of "advantages" & "disadvantages" doesn't make any sense.
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.
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.
Water is cheap & 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.
Unless you live on a space station or the desert planet of Arakis, it is foolish to be that stingy with water.
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.
The main downside is it leaves a ton of salt residue on your bags and you have to wash them off.
I have purchased 6 of the 5" x 3" packs and 10 of the smaller rounds hand warmers of eBay. I use them for localized heat on my shoulder.
I may be able to help you with an answer re the clicker. when I researched these before purchase I found an article that said the crystallization reaction that produces the heat is started in the tiny indentations that are on the disk.
The disks have been pressed to produce the cup shape that makes the thing click, but on closer examination there the lateral indentations on the disk are you can see that the disk is actually perforated along the indentation, these perforations are almost invisible as they are press made. The reaction stats from this point, the reaction is started when the edges of the perforated slot snap past each other and this is where the seed crystal is formed that starts the chain reaction that makes the heat.
I think the disks are made from stainless steel.
All my packs need reactivated or i would post a close up of the clicker.
Rather than have a large vest type warmer that is difficult to reactivate, and also gives you that suicide bomber look ( just one twitchy cop and it could be game over) Have you thought of making smaller warmers and sowing lots of pockets onto a t-shirt or waistcoat ( this will give you the professional shop lifter look if worn without the warmers)
I have a fleece travel pillow that can store 4 of the 5"x 3" packs i put the reactivated packs in while they are still hot and it acts like a hot water bottle for a few hours until they have cooled. This is also useful if i wake in the middle of the night the pack is at hand and this saves me getting out of bed to fumble around trying to find a heat pack.
My view on reactivation is that i find that some of my commercially bought ones need to be boiled vigorously to get all the crystals to dissolve.
.I intend to make some sore of basket that can be placed in a large pot so i can reactivate the packs on the wood stove in the shed and not waste gas I will post an Ible on whatever is come up with.
As for smaller warmers vs larger ones, I have made both, I prefer the mid sized to larger ones. I like the vest idea. If you make one I would love to see it. I think it would be important to make sure the vest has insulation so that it only allows heat to escape toward the body.
Along those lines I have tried other methods of heating them up with varied success. Smaller ones can sometimes be successfully reactivated in the dishwasher. I have also used a crockpot to reactivate them (takes forever but it works).
The problem is that I want faster warm up times and safer methods. Even boiling has its problems. My dad ruined a few of his hand warmers because he forgot about them and boiled all the water out. Fortunately he didn't start a fire.
It seems to me the best way to reactivate the sodium acetate would be to heat it directly. Some sort of heating element in the bag itself that will only heat up to 140-150 F (60-65 C).
The difference between the melting point and water simmering at 70c or boiling at 100c isn't enough to make a difference in infusing energy into the SA.
If you want to put more energy into the pack, then I would suggest using a pressure cooker so that the water temp can go above 100c, but the danger involved would not be worth it.
Puting metal in the bag is a waste of time if all you want is for it to heat up to 60c. Water can be kept at that temp more easily than hotspots created by a heating element.
Simplest thing to do is when you're done with them, take them home and put them in the crockpot. Probably the most energy efficent method and kindest to the vinyl or plastic bag.
I just did a quick search on DuckDuckGo.com for "Empty IV bag"
But there is no reason you couldn't try it. Make one, put it in a ziplock bag with some solution and see if you can get it to work.
I have miked vinegar and baking soda and now have a salty sludge at the bottom of a bottle but don't know what to do with it.
I have found that some of the ones i bought have very sensitive clickers that you barely need to touch and others need clicked several times before the reaction occurs
I will probably make some of these as I like to hunt and it gets really cold outside when you can't move to keep warm. The shorter lifespan kind of worries me, but I could counter that by using more.
The disposable ones take a long time to heat up and without a constant oxygen supply they lose their heat rapidly (such as in your boots).
with the vinyl I was thinking that you could create some really unique pocket designs. For example you could create a little sleeve that you could put on your foot and then slide that into your boot. This would keep the heat where you want it and you could even create "heat channels" going down the sides and bottom.
A *free* source of stainless steel spring steel is from a worn out car or truck windshield wiper blade. They can be found in abundance in the trash cans outside any auto supply, late in the day on the day AFTER it rains. (Guess when people most often replace their blades? :-) On each outing, I typically find between 8-15 discarded blades outside of a single discount auto parts store.
To harvest: Only one end is secured, by squeezing a notch. Find out which end that is, then bend the frame's C-clip open slightly with a pair of needle nose pliers. This allows you to remove the blade from the frame. The stainless steel flat spring "plates" should easily separate from the rubber. Recycle the rest. If harvesting on the spot (which I normally do), one discarded plastic package from the replacement wiper blade sale can hold all of the collected straps. The remaining old wiper materials goes back into the trash can, and you walk away with a package of straps. (It now only takes me a few seconds with my pocket Leatherman tool, to harvest the steel from a found blade.)
Many blades yield a tiny pair of small steel straps, which may be difficult to form into an activator (experimentation is needed here...) But many "winter" and truck wiper blades yield a much larger, single strap. One processed wide strap should yield a number of activators.
If anyone attempts to make an activator from a discarded wiper blade spring steel strap, please add a comment HERE, to let us know if and how well that worked!