Cooler Gel

[nivram4491]

Some time ago I bought some cooler gel packs from Daiso. Now I can't find them. Has anyone seen them recently in a Daiso store?

[FolkGuitar]

I haven't seen them, but I've made a few recently. Just an ordinary washcloth inside of two zip-lock bags... Wet the cloth and don't wring it out, then pour on some ordinary rubbing alcohol and put it into a zip-lock bag. Put that one inside another, zip it shut, and freeze. Gets much colder than ice cubes, doesn't drip, can be folded to size before freezing, and made to fit any size container.

[surangw]

I haven't seen them, but I've made a few recently. Just an ordinary washcloth inside of two zip-lock bags... Wet the cloth and don't wring it out, then pour on some ordinary rubbing alcohol and put it into a zip-lock bag. Put that one inside another, zip it shut, and freeze. Gets much colder than ice cubes, doesn't drip, can be folded to size before freezing, and made to fit any size container.

not to doubt you , but doesn't the temp depend on how you freeze it?

[Konini]

Sounds as if that's working the same as vodka in the freezer. It doesn't freeze solid, but after a few days in there it's thicker than cough syrup and nice and cold. I think I've read about Russians dying this way, leaving their voddy outside in the minus whatever it gets in Siberia and drinking it straight. Must be a lot colder than my freezer because it's the voddy being so cold that does something to their innards and kills them.

[FolkGuitar]

I haven't seen them, but I've made a few recently. Just an ordinary washcloth inside of two zip-lock bags... Wet the cloth and don't wring it out, then pour on some ordinary rubbing alcohol and put it into a zip-lock bag. Put that one inside another, zip it shut, and freeze. Gets much colder than ice cubes, doesn't drip, can be folded to size before freezing, and made to fit any size container.

not to doubt you , but doesn't the temp depend on how you freeze it?

Good question! And the answer is : Yes, of course. The colder the freezer temperature, the colder the gel pack will become... up to a point. Amount of alcohol in the mix + freezer temperature = final result.

Water can only freeze to 0°c, but pure Ethanol freezes at -114°C. As more alcohol is added to water it lowers the freezing point of the solution. So the actual temperature of the 'freezer' combined with the amount of alcohol added to the wet cloth will be the determining factor in the final temp of the pack. As most home freezers don't go down to -114°C, the home-made gel pack will probably be slushy rather than solid, BUT.... colder than most commercial gel packs, as they DO freeze solid at home-freezer temperatures!

Edited April 30, 2016 by FolkGuitar