Reusable Hand (or Anything) Warmers

If you get cold hands in winter, you want a nice warm pillow to lay on, or if you just like warmth, try these reusable hand (or other) warmers! Based off of the commercial ones, it is essentially just a bag of sodium acetate with a metal thing inside of it. Sodium acetate is a chemical that heats up when crystallized. That's what the metal thing is for--when you press on it and let go, it acts as a place for the sodium acetate to start crystalizing. You ca scale it up or down to make it any size you want. But the best part is, once it's all crystalized and eventually stops being warm, you can submerge the bag in hot water, and it will melt back into a liquid and you can use it again and again.

If you choose to make a smaller hand-warmer sized one, you can actually make sodium acetate yourself using regular white vinegar and baking soda. However, it will have to be boiled down a lot and will take some time, so if you're choosing to make a larger one I would recommend you use commercially available (and relatively cheap) sodium acetate. Another thing to note is that making your own can be quite stinky so if you decide to do it you might want to do it outside or under an exhaust hood.

if making the sodium acetate, you will need:

1. white vinegar (amount depends on how big, it boils down a lot. 2-3 liters will probably make enough for one small hand warmer)
2. baking soda
3. a stove or hot plate (preferably a hotplate with a magnetic stirrer)
4. if not using a magnetic stirrer, something to stir with

if not making sodium acetate, you will need:

1. anhydrous sodium acetate
2. water

either way you will also need:

1. an alligator clip
2. some relatively thick, durable vinyl sheeting, preferably clear. Or a durable, waterproof, and heatproof bag that can be sealed.
3. a large pot or beaker
4. parchment paper (if making the bag)
5. food coloring (optional)

Take your vinyl sheeting and cut it into two pieces of the same shape and size to turn into a bag. Cut a piece of parchment paper of the same shape but a bit smaller, so that when it's placed inside the bag there is around 1/2 inch seam around the edge. Put it in a 350*f oven for 3-4 minutes, and then let it cool. The vinyl around the parchment paper should have melted together and formed a water tight seal. Cut out a corner big enough to take out the parchment paper and pour in the sodium acetate later on. Take out the parchment paper from between the sheets. Alternatively, you could seal around the edges with a curling iron or clothes iron.

This method is not much cheaper than using commercially available sodium acetate, but if you want to use what you have at home, this is how to do it. Take as much vinegar as you're using, it will boil down about 90%, and add it into a pot or container. Use a container a good bit larger than the amount you're using, as when you add the baking soda, it will fizz a lot. Next, add baking soda in small amounts, and stir. Keep adding more until it doesn't fizz anymore. Start boiling it down. It might smell a little strong, so you might want to either do it outside or under an exhaust fan. If you have a stirrer, turn it on, if you don't, stir occasionally. If the solution starts turning cloudy, add a splash more vinegar. . This process will take a very long time, and the more you make the longer it will take. After a long time, there should start to be a film of crystals on top. Take it off the heat here, or if you go a bit longer the product will be a bit thicker, which isn't really a problem. If you want to change the color, add a few drops of food coloring.

If you are making a bigger one, it would probably be a better idea to use store bought sodium acetate, as it will take a very long time to make your own. You can play around with the amounts, but it seems to work to use 1 cup of water for 1 1/4 cups of sodium acetate. Put the water in a pot and bring it to a boil. Add in the sodium acetate and dissolve any lumps. Once it is all dissolved, there should be a thin crusty layer on top. If there isn't, either boil it until there is or dissolve in a little more sodium acetate. If you want to change the color, add a few drops of food coloring.

Before you cool down your solution, add a little bit into a thick sealable bag--enough that you can pool it in a corner and drop in the alligator clip. Cool it down in ice water until it is around room temperature or below. Pinch and let go of the alligator clip and it should start a reaction. If it doesn't, your solution probably isn't concentrated enough. Add it back into the rest and add some more sodium acetate to the solution (make sure the solution is still hot!), and dissolve it in and try again. Make sure to melt it all back down afterwards.

Now, pour the sodium acetate solution into the bag along with the alligator clip. Make sure to leave enough room in the bag to squeeze the clip without the bag popping. Squeeze the alligator clip and let go to crystalize the solution. Using a big of paper towel or rag, make sure the hole you're going to be sealing is clean. If you are using a homemade bag, seal it with a curling iron, or something that could melt the vinyl and form a seal. If you're using a different bag, seal it as appropriate. To use the warmer, open the clip and then let it snap back down. To reuse, submerge it into hot water until all the crystals are melted and you're good to go again and again. The crystals should melt around 136 degrees fahrenheit.

If you have any comments or ways to improve please comment below!