[piomar]

Hello everyone,
I'd like to make my own hand warmer, so I bought sodium acetate and made a solution. When I put some solid acetate, it starts solidification. But, I'd like to close it in some kind of container and initiate solidification with fixed trigger located inside. I read some articles about the trigger. It's usually a metal disc or a tiny stick which releases small crystals when is pressed. How does it work in details and how could I make it on my own?
Thank you in advance for any answers. [;

[Grundalizer]

put a little bit in the corner of a sandwich baggy, pull the corner out so it rips off some extra plastic and breaks.  Then twist it into a tiny little tear drop and use a lighter to melt it closed.  People do this a lot to store drugs.

THen put that little piece of plastic containing your seed crystals into another sandwhich baggy which is zip locked shut and contains your saturated Na Acetate solution.  When you rub the small piece rough enough it should rupture and give you crystalization

[Borek]

That would work once only.

You need a piece of metal, slightly folded in such a way that it clicks when bent. That click is usually enough to start crystallization.

[piomar]

I agree with Borek. I need something that is reusable. When I was reading articles about hand warmers, I found an interesting patent: http://www.google.com/patents?id=unU7AAAAEBAJ (4077390). There it's written that the metal trigger should have small fissures or slits to initiate solidification. And it doesn't need to be 'clickable' but flexible only. Do I think properly?

[Grundalizer]

Try going to the local hardware store and buying a piece of tin and then using an old fork or knife, dig a bunch of slits and scratches into it.  The only problem with that is that once you insert it into the solution it might instantly crystallize.