how do i made one of these

>>1006366
How, why and does it work like you intended?

Buy a diaper that uses gel, soak in water, extract gel, place in ziploc freezer bag, freeze, done. An it wont leak.

>>1006366
Its just silica gel in a bag really

>>1006417

Do this,but if you soak the diaper gel on rubbing alcohol so it doesn't freeze and you don't end with a hard block of gel.

>>1006417
>>1006420
Or you could just buy a pack of gel for like $5 and make a whole bunch of cool-packs.

>>1006531
Making your own cold packs is not cost effective unless you need them to be a particular size/shape which isn't readily available.

Why not use ice? The phase-change part is what soaks up all the thermal energy.

>>1006675
Icepacks do use ice, they just have additives which make the ice form into smaller crystals rather than one solid block of Ice. Since the smaller crystals have a greater surface area, they can melt faster, providing faster cooling, and freeze faster, since a solid block will take a long time to freeze all the way to the centre.

>>1006675
Because ice expands as it freezes, and water leaks everywhere out the smallest hole.