[friendzis]

Gloves are not inherently bad, but the risks they do not protect from are not obvious. For the sake of this comment room temperature is 0 heat, cold is negative heat (offset scale).

Gloves are not a perfect insulator, therefore they absorb heat and cold. It takes time for the cold to permeate the gloves - i.e. you observe significant temperature gradient over thickness of the glove. By the time your hand feels the cold, the whole width of the glove is bloody cold. In order to remove the cold from the glove you need to heat it. The only heat source is your hand inside of the glove, therefore the heat is taken from your hand. You need as much heat from your hand as much cold you have taken from LN to bring the gloves to 0. Unless you remove the gloves when the cold starts to permeate - hello frostbite.

While Leidenfrost effect allows one to splash LN on their hands without any or at least significant damage, gloves simply allow more splashes, not full immersion. Handling LN with gloves is a delaying technique, gloves do not magically protect from cold.

[dreamcompiler]

It's sort of similar with very hot things. I'm a blacksmith, and I rarely wear gloves. Steel is a poor conductor of heat, so if you grab it just a few inches away from the red-hot end you're fine. If you hold it too close, you realize it instantly and let go before any serious damage happens. But if you wear cotton gloves for a while, you'll grab the steel closer to the heat without realizing how hot it is, and then the accumulated sweat inside the glove suddenly vaporizes, and you get a nasty steam burn before you can get the glove off.

[samfriedman]

Similar thing working in a kitchen: always grab things out of the oven with a dry towel. Use a wet towel once and you'll never make that mistake again: the steam exploding against your skin will hurt you a lot more than the metal on your bare skin would have.

[jonhendry18]

Similar with calfskin welding gloves. They'll protect you, but if you grab something really hot, after a moment you end up with a really hot piece of calfskin against your skin. And when you let go of the hot metal object, you still have the hot calfskin against your skin.

[Retric]

This depends on how insulated they are. You could make gloves that allowed you to stick your hand in -200C all day long. It's the same reason winter coats work, slow heat loss below the body's heat protection and you get unlimited duration.

The problem is most gloves are designed for vastly warmer temperatures and you don't notice frostbite if your hand cools down slowly.

[semi-extrinsic]

> You could make gloves that allow you to put your hands in -200C all day long

I don't think so. The only way you could make an object like a glove for continuous LN2 exposure, and not have it be 2 feet thick, is multilayer vacuum insulation (like LN2 dewars use). But that would not let you move your hands or fingers at all.

[Retric]

Check out polyimide aerogels, it's flexible and has ridiculous insulating properties. On top of that your hands are providing heat which makes a big difference.

Though I suspect mittens are probably far easier to manufacture as that's what current designs for -60c use. Either way you are not going to have much flexibility, but could grab something.

[tjoff]

I don't doubt that you are right. But that whole description could, to my inexperienced ears, just as well be an argument as to why you really really should be wearing gloves at all times.

If the gloves slow down the process enough so that when you feel cold you have time to put down the container and remove the gloves (less than five seconds?). I mean, to me I'd imagine that is the sole purpose to wear them in the first place?

It would, I imagine, also help from panic. If you notice that you got LN on your gloves there is less panic than getting it on your skin - less chance of a reflex reaction that just makes things worse.

[friendzis]

You are correct, one of the main purposes for wearing gloves when handling really cold/hot materials is to provide that time cushion to handle the thing or contain accident safely. The question was why gloves are not necessarily a good preventative measure.

For example if you are arc welding and some nasty blob of molten metal drops on your hand, gloves will provide "heat through" time cushion to remove the gloves more or less safely (easily removable layer also helps avoid hot/cold blob sticking to your body), but keeping the gloves on will most likely still result in a burn. There is a hidden danger with cold that cold does not radiate like heat and we have much less intuitive understanding of how cold affects the skin. Sometimes people get frostbitten during winter activities without them noticing that something was too cold for too long.

[jonhendry18]

What if your hands have sweated, and your skin freezes to the glove material? Removing the gloves might be difficult to do quickly.

[brusch64]

Thank you - this makes perfect sense !