Reusable handwarmers that get hot by freezing

Opublikowany 29 sty 2021
These things are so cool they're hot.
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  • Hi! Through this video, we've apparently uncovered another one of those fun continental divides. It seems the reusable kind is quite common across Europe, and the disposable kind is almost unheard of! Wouldn't ya know. Since I assumed the situations were similar, I'll add that the most significant advantage of the oxidation-type is that they last _hours_ and not minutes. During the B-roll shooting, the handwarmer you saw me open was still nearly as hot as a freshly-opened one 4+ hours later! And these were very cheap. It's through that lens that I made the judgment that the reusable kind are pretty meh - I'm simply accustomed to something that will reasonably last an entire workday. My take is that given the sustained heat output and fairly inert materials the disposable ones are likely roughly on-par to the reusable ones with regards to environmental costs, especially when you factor in energy spent to re-activate the reusable ones. But that's just my opinion! I hardly use these things at all, really, so I've got no skin in the game.

    • Why does the heat output seem to drop off with successive uses? That's something I've noticed and never understood about these.

    • 1.1 million views !!.. one of the most successful videos of the channel .. :-D

    • The heat energy used to reactivate the reusable ones isn't really a concern since 9 times out of 10 it will be done in a heated room. So any heat lost to the room from the boiling water will go towards heating the room and thus less load on the heater.

    • You failed to mention that it's one of the primary ingredients used in manufacturing methamphetamine and that's the only reason they're still available to this day.

    • @Jacob Houston cool! Took like 15 minutes but it worked!

  • I bought one of these and its so nice for arthritis. It isn't as warm as the disposables and is a much more manageable heat and lasts about as long as is really needed to help circulation very cool

  • As a chemist, I have a problem with your logic; why does it feel like you're implying that if a solution of sodium acetate is cooled to below the m.p. of sodium acetate, sodium acetate wouldnt be able to remain in solution? The way you talked really implies this imo

  • I do agree that as hand warmers for remaining warm, the oxidation-type are probably better, but I noticed something interesting regarding heating for pain relief - would it be possible to hold the pad in a curved shape - say around a sleeved arm - and get it to solidify in a shape that would fit wonderfully around a sore arm? That then would stay that way and be very effective for that?

  • One time one of these broke in my backpack at school

  • I used to use hot hands at my old job in a frozen food wearhouse worked great just overtime was hard because they cold after 8 hours so I'd have to wait and not use them for the first 2 hours

  • my refrigerator freezes liquids into slush if you put it on high

  • so the non reusable ones are basically on fire

  • Great for bicycle or motorcycle riders once you dismount - great for getting hands back to temperature that can regulate with pockets or indoor conditions

  • This show would fit perfectly on PBS, down to the outro music, I just love it

  • I found this channel on my school Chromebook interesting


  • Of course he mentions refrigeration!! 😂 You are such a beauty!

  • So cool. Sorry, hot.

  • the main benefit to the reusables setting them off is entertaining

  • Would you say that most of the materials for the Hot Hands packs are... "dirt" cheap?

  • Sodium acetate is cool! ... No, it's supercool!

  • The iron-rusty ones reminds me of Flameless Ration Heaters found in MREs.

  • The reusable ones look like the ice packs that are fun to squish before you put them in the freezer.

  • bringing this to school be like: "can I borrow?"

  • In my house I recharge mine whenever I steam vegetables or after I've cooked pasta. On my boat I have a pressure cooker, which lives on the multi fuel wood stove. It heats the reusable pads for free (the wood is collected from the forest floor).

  • "This is one of my favorite objects I've ever encountered" I love your autistic tendencies

  • Time for a haircut my friend.🤠💈

  • The reusable heat pads aren't as energy inefficient as you're making out. The energy lost while boiling the water will go towards heating a room thus reducing the load by that amount on the heater since they will almost certainly be recharged in a house with a heater.

  • I wonder what would happen if you add a little water on the black powder?

  • There are large-scale versions of these packs (or rather, the material inside) that provide heat storage in domestic, commercial, and industrial settings.

  • You could put zeolite molecular sieves in a metal mesh in a zip up bag you fill up with water to get some instant heat. They would be reusable, just take out the metal mesh from the bag, dump out the water, cook the mesh bag with the sieves to boil off the water and store it in the bag to add water later on for reuse. I suppose it's a wonderful product idea for someone, or for a homemade and arguably safer alternative and definitely longer lasting.

  • 1:29 😂 An iron joke! Yes!

  • Anyone else get that reference at 3:30 ? Mostly harmless.

  • His attempts at comedy are, sometimes, cringe worthy! 1:29

  • That part right down the middle of your head us awesone!

  • Our delightful narrator has combed his hair. How interesting.

  • They've been around for decades...and even now that they've been dyed blue, they still suck.

  • Mostly Harmless? So tell me have you seen Arthur Dent lately?

  • I love the zippo catalytic handwarmers but they too suffer from getting much to hot to hold while also not really giving enough heat to keep in a pouch. Basically just nice pocket heaters

  • im kind of concerned about if it can kill you

  • my siblings and I used to put them in the microwave to heat them up again. Worked pretty well ... until it didn't and one of those things popped.

  • Is nobody using the ones you fill with lighter fuel anymore? They glow for hours and they last decades.

  • You can make these at home. The ingredients are *Vinegar* and *Baking Soda*

  • We have those reusable things here and use them in combination with a hot water bottle, since they are quite common in germany. We start our trip by heating the reusable heaters and then use the hot water in the water bottles to apply immediate heat to say a babies stroller. Then when the water bottle cooled down, which by the way can take several hours, we activate the reusable ones to make our way back to the home. This way I think we used them most efficiently by using the heated water anyways and not getting rid of it after heating the things.

  • They may not be good hand warmers, but could be great tool to demonstrate and teach how that works in school and in science class! ☺️😁😉

  • I used to get these much cheaper from the Pound store.

  • PRO TIP: If you need to go out in the cold for a short time, and don't want to waste the 7 of the 8 hours of your disposable hand warmers, just place your "hot hands" in a zip top freezer bag when you come in and squeeze out all the air. I have found that they will last for over a week this way for the next time I need to run out for a few minutes in the cold. Waste not want not!!

  • "I was trying to get an interdimensional portal going, so I got these one's too...."

  • What about using them to warm up food?

  • P O C K E T

  • When cold-weather camping, put one in your boots before you put them on in the morning.

  • Sounds like the spent Hot Hand material would be a perfect soil additive for your house plants.

  • another common example of latent heat that i just learned about is the warming of cold drinks as condensation builds up on the outside of their container. i read a study by a can "coozie" maker that said it is the latent heat due to water condensing on the outside of the container which is the majority contributor to warming the drink as opposed to the simple absorption of heat from the surrounding air. so the coozie's job is actually to keep water from condensing more than it is to stop heat from transferring in, which is why they can be effective even when rather thin. another related concept i rant about sometimes is the fact that drinks with ice in them are cooled the most by the ice melting, not by the ice changing temperatures to become warmer ice. the heat of enthalpy of water is just way higher than its specific heat, meaning it takes a lot more energy to turn some quantity of warm solid ice to cold liquid water than to turn that same quantity of cold liquid water to hot liquid water. you can buy ice molds for big ice cubes that claim to not water down your drink, which is kind of true, except that it means it's just cooling less effectively. if you're ok with that trade-off then we're good, but it's just misleading to claim it's the same cooling with less dilution, because if it isn't melting as much it just isn't cooling as much.

  • "boiling them gets old fast" Me on my twelfth boiling session: *are you sure about that?*

  • Are they shock sensitive?

  • 4:32 so we got empathy and supercalifragilisticexpialidocious

  • MDrives will be the next to hit the cesspit of time becuase the technology behind it is the same as Blu ray and DVD and CDs. It writes to a very expensive disc with a reasonable priced disc writer using the same software the aforementioned disc uses. The only difference is you are writing to a disc with rock base or metal layers so the data is stored for at least 1000 years because the old discs used a inks to write on. Now TDK DVD discs were the most reliable because use a rock basis the same as MDiscs.

  • That is hot ice

  • hot hands are a mild thermite?

  • ice-nine!

  • "Oh wait, it's rust! How ironic!" It's funny because rust is totally ironic ( Iron(III) Oxide ).

  • "it's rust! how iron-ic" lololol

  • Love these things! We used these as hot rocks for taking our bearded dragons to the vet if needed. Ahh, good memories. The ones we used in the late 90's turned rock solid and were a nice pale pink and pretty rounded. They had a good volume to surface area ratio. You continue to make great videos!

  • I put these in my wetsuit when I go scuba diving in the Winter

  • No

  • I here in germany i didnt even know about disposable handwarmers.

  • knock knock is there a reusable cooling pack because I want one

  • 04:37 wait what HhhOOOWWWW ?

  • "it says not to open puncture or tear... Fortunately, I have scissors and a propensity to ignore safety instructions" Best line ever

  • Now I am wondering what happens when you put the reusable ones in the microwave.

  • Hmmm what about putting it in your pocket along with your hand and then when it gets too hot you can take your hand out the pocket and it would still be slightly insulated

  • Hot what

  • Doesnt this break the law of conservation of energy. Hmm.... I'm thinking if a way to make a perpetual motion waterfall out of this in a terrarium setting. One sec

  • Fun fact! Everything releases heat when it freezes. The reason we don't normally notice is that we usually have to cool down the surroundings to pull the heat out of the liquid in order to freeze it. Stuff doesn't get colder because it freezes, it freezes because it gets colder. Another fun fact! This is currently believed to be what keeps the interior of the Earth hot. The inner core is (very) slowly solidifying, which releases enough latent heat of fusion to keep the outer core liquid.

  • TC you are a national treasure.

  • i killed one as a child by using the microwave to recharge it. it works but the metal thing will melt the plastic.

  • Is the concept of non-reusable warmers similar to the heating pouches that are "flame less heater"? As seen in some adventure food packs or meals ready to eat.

  • oh boy icecreamsandwitch twitter fans your wish came true

  • My father introduced me to these things as a child. They may not be energy-efficient but for long expeditions into the woods of the North Country, or for hunters, I'd say these are very useful! It felt so good to stick a pair of these into my gloves after an hour outside in near-blizzard conditions. Happy childhood memories :)

  • That corona isolation hair though... I hope you can get a haircut sometime soon, Shemp. :D

  • Everyone has them in Germany😂 It's popular in winter when students have breaks. I remember we used to switch heat packs with friends and classmates bc there are a variety of colours, shapes and texture so it's cool to try them out.

  • I never boiled these things. They used to just melt at room temperature after a day or two. You could also just put them on a heating surface to melt them.

  • I’m happy with my Samsung galaxy grenade, thank you. It warms up the whole room!

  • Me buying the packs and opening them to find who asked...

  • Very cool. One thing, though - isn't this latent heat of crystallization? As I understand it, this is dissolving and precipitating, not melting and freezing.

  • seems useful for going on hikes in the snow

  • So, thermite-lite?

  • im from finland and have never heard of these. just get proper gloves and clothes if its cold...

  • Where can i get one

  • What about those squeeze bag ice packs?

  • I remember these things when I was 7 OMGGGG

  • the title just made me lose braincells.

  • i dont know why im watching this but for some reason i don't know what a Hand Warmer is

  • This video: *Exists Medieval People: IT'S A WIIIIIIIITCH!!

  • I can see these as being useful for mild to moderately cold weather camping. Just pack a bunch of them with you for you and your companions and just melt them while you go to boil your water for cleaning. Better than using disposables that you may have to carry out with you anyway.

  • Technology Connections doesn't know what Ice-nine is

  • I strongly disagree with denying the usefulness, the bigger ones are great for pets during the winter, better than an electric heating pad as they're quite inconsistent often heating less or even more causing a fire hazard as well as raising the electricity bill. It takes about 10 minutes on high to defrost and last for 3-5 hours (of course depending on the size, I have a medium pad) fully understand for hand warmers though

  • I used to put these in my pockets to warm my hands up before hockey games, only needed about 10-15 minutes of warmth as after that I would be running around and wouldn't be able to use them anyway... they worked great for that purpose which was once a week every week during winter so didn't have to boil them too much (once a fortnight as I had four of them).

  • Me seeing the tumbler: Why the hell shoto is there

  • In Europe there are companies researching to make warm water tanks to work with that principle. Activating the sodium-acetate to make a huge amount of warm water instant. And "recharging" or "regenerating" the substance later when e.g. your solar heat collector reaches operating temperature.

  • Large disposable ones are sold as sleeping bag warmers. They are about 4X6” and fat. They stay warm for about 10 hours. They are too hot to keep against the skin. They’re great for the foot box of a sleeping bag. Two will actually noticeably increase the temperature in a small tent if the vents are closed.

  • Seems like you could cheat a fair bit by in the remelting process if you just take the water you use for cooking something like pasta when you strain it and then use it for the packs. You'd at least skip the boiling process since you'd have water that was already boiling, you'd just have to keep it warm for long enough to do it's job. Though it might come at the cost of having your hands smell like warm spaghetti.

  • Hot Ice! So THIS is what Daniel Stern was talking about in the movie "Rookie of the Year

  • If you were to cool them even further below their freezing point after boiling and cooling via dry ice or liquid nitrogen would they release so much heat energy that they could combust?