A question for the Chemists …

[Michael GilliganParticipant @michaelgilligan61133]

[Michael GilliganParticipant @michaelgilligan61133]

I have a number of the ‘crystallizing” hand-warmer sachets

[ the content turns to liquid when heated, and outputs heat when crystallization is initiated by a metal ‘clicker’ inside the sachet ]

As a practical hand-warming device, they have proved near-useless to me.

Question: What is the chemical inside, and is there anything interesting and/or useful that can be done with it ?

MichaelG.

[BizibilderParticipant @bizibilder]

Explained here: **LINK**

[Brian WoodParticipant @brianwood45127]

Hello Michael,

From the dim past I recall the material within is Sodium Thiosulphate. It was used to yield an exothermic release of heat on recrystalliization, usually initiated by kneading the bag it is contained in. Maybe your 'clicker' doesn't work, I don't remember that as the reaction initiator

As for your supplementary questions, maybe Wikipedia has the answers.

Regards Brian

[Bill Davies 2Participant @billdavies2]

As Bizibuilder's links indicates, it's sodium acetate. Perhaps Brian is remembering some long-ago 'chemical' photography, like me. Sodium thiosulphate was used as 'fixer' after developing the image, at least in black and white photographs.

Bill

[Michael GilliganParticipant @michaelgilligan61133]

Thanks folks

… I will decant all the contents into one container and label it accordingly.

MichaelG.

.

Ref. https://en.wikipedia.org/wiki/Sodium_acetate

Edited By Michael Gilligan on 14/03/2021 13:45:40

[Brian WoodParticipant @brianwood45127]

Hello Bill,

Your memory of sodium thiosulphate's use in photography is as mine, but I do also recall it being used in hand warmers that were activated by kneading the sachet. As usual, the contents of those things was not disclosed to the buying public and that was what I had been told at the time.

Regards Brian

[not done it yetParticipant @notdoneityet]

Thiosulphate is one of many possibilities. Sodium acetate is a safer chemical and more reliable for activation.

**LINK**

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