Each pad contains a a solution of Sodium Acetate (form of salt) and a stainless steel disc in a sealed plastic bag. Flexing the metal disc in the bag causes a single molecule of the solution to crystallize which in turn causes the entire solution to solidify. This change causes the hand warmers to heat up to 129F / 54C. Depending on the size they will stay hot for 15 - 120 mins (depending on size) then gradually cool down. The warmers can be used over an over again by recharging (boiling) them.
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How to Activate
1. Flex the metal disc back and forth until you see crystals form and the pad begins to warm up.
2. Knead pad to soften.
How to RechargeTime: approx. 5 - 15 minutes.
1. Boil a pot of water.
2. Place a cloth or small plate at the bottom of the pot.
3. Place the pad on the cloth inside the pot and continue to boil the water until all crystals are dissolved and the pad is completely clear.
4. When the pad is completely clear, (only liquid remains), take it out of the water using silicone tipped tongs, and place it on a cloth or counter area to cool down.
5. If crystals start to form while the pad is cooling,
repeat steps 1, 2 and 3.
6. Let cool and then Re-use!
Issue: After cooling, heat pad reactivates and becomes hard.
Cause: This issue may occur when crystals remain because the heat pad has not been boiled for an adequate length of time.
Solution: Re-boil pad for a longer amount of time ensuring that all crystals have disappeared before allowing to cool