How does a hand warmer work? - explained
Hand warmers are compact accessories that provide warmth to users for a set period of time. Their operation is easy and they are useful for anyone who spends time outdoors on cold days. In this article you will learn how a hand warmer works and how to use it depending on the type you choose. We will also give you tips on how to reuse a gel hand warmer.
Hand warmers - working principle
You will find several types on the market hand warmers, and each is based on a slightly different operating principle. Below is information on how the four most popular types of heater work:
Chemical iron-air heaters
The principle of the chemical hand warmer boils down to a simple oxidation process resulting in the release of heat. Inside the hand warmer are powdered iron, water, salt, activated carbon and vermiculite (a mineral with thermal insulating properties).
Heat is generated by the rapid oxidation of iron (rusting), which leads to an increase in the temperature of the powder. The salt speeds up this process and the activated carbon enables the heat to be evenly distributed. The vermiculite increases in volume under the influence of the temperature, allowing the heater to retain heat for longer. This process occurs so quickly that the temperature can reach up to 60-70 °C.
These types of hand warmers are designed for single use and keeps you warm for up to 12 hours.
Chemical gel warmers
This type of hand warmer is designed for repeated use. How does a gel hand warmer work? Inside the sachet is a gel solution (usually sodium acetate), and a sheet which, when bent, triggers a crystallisation reaction of the supersaturated solution. This causes the temperature to rise to 50-60 °C.
The gel heaters can be used repeatedly, as once the pouch is immersed in boiling water, the salt crystals dissolve and the solution is ready to be reactivated. They typically provide heat for about 60 minutes.
Catalytic petrol heaters
These are hand warmers that resemble a large lighter in appearance. They work by oxidising petrol. For activation, it is necessary to heat (e.g. with a lighter) the catalyst inside (usually a piece of platinum).
Petrol heaters are reusable - all you need to do is fill them up with the right fuel, generally lighter petrol. Depending on the amount of fuel poured in, the petrol heater can operate continuously for 12 to 24 hours.
It is worth knowing that these types of heaters can generate an odour, so they are best used in areas where ventilation is provided.
Coal warmers
Carbon hand warmers are usually metal containers that are filled with glass wool on the inside. A briquette made from a compressed mixture of charcoal, sodium silicate and a saturated solution of potassium nitrate is placed inside. The heat in such a heater is generated by slow combustion of the briquette.
The coal heater is characterised by good efficiency and its operating time is up to 8 hours. The heating time and temperature can be adjusted by adjusting the size of the insert and how it is lit - on one or both sides.
Like petrol heaters, these too can generate an odour, so they should be used in ventilated areas, preferably used outdoors.
How to use a hand warmer?
If you don't know how to use a hand warmer, then read the instructions, as the way it activates depends on the type chosen. However, chemical heaters are the most popular, and most of them activate in exactly the same way.
How to use a chemical hand warmer? Simply tear open the packaging and expose the warmer to air. The oxygen will start the reaction. It is a good idea to speed up the process a little by shaking the warmer for about a minute. Then you can slip it into the gloves, socks, under jacket, or even into a sleeping bag.
How to reuse a hand warmer?
As we mentioned earlier, reusable gel warmers are popular on the market. How do you reuse such a hand warmer? Simply follow the instructions below:
- Place the heater in a pot of hot water.
- Cook for approximately 8-10 minutes.
- Remove the heater from the water and wait until it has cooled completely.
- The plate inside the heater is again ready to be activated by bending.
When cooking, be careful not to overheat the heater as this can damage the pouch.
Body warmers offer at Militaria.pl
Looking for a way to keep warm in the field during colder days? At Militaria.pl you can buy chemical, gel, catalytic and charcoal heaters. Whether you're going trekking, camping, survival or just want to warm up while walking, the heaters we offer will keep you warm for hours.
We offer a wide range of body warmers that effectively keep you warm in all conditions. You can put them under your gloves, in your boots, under your jacket or in your sleeping bag when you spend the night in the wild. We offer products from brands such as Artus, Mil-Tec, MFH, Mr. Heather and many others.
