I know a few members hail from the parts of the UK, where at time of year ,winds get cold and temperatures get lower than ladies of the night skirts. But I've spotted windscreen wash to day in B & M ,that's said not ot freeze till -20 . It's called DEMON FREEZE, AT CIRCA £3 PER BOTTLE.

I've used screen wash that was stored at ~-20C, where it was still liquid, and it still froze on the headlight covers (and the wiper blades too)!

Sometimes whatever is in there to make them liquid at low temps (alcohol?)  can evaporate when it hits the screen and what's left then freezes.

Edited 8 March, 20197 yr by Aspman

You also have to take wind chill into account.

 

I find it can be safer to have a hydrophobic layer on the glass than use either the wipers or apply screenwash in certain conditions. 

Windchill is something felt by human or animal.

Cold / wind speed. 'Feels like'.  Not actually a temperature. There is a sliding scale on the drop of body temperature.

 

Edited 8 March, 20197 yr by Skoffski

1 hour ago, Skoffski said:

Windchill is something felt by human or animal.

Cold / wind speed. 'Feels like'.  Not actually a temperature.

Want to come up here and tell my car that?  

What happens does it get blast frozen?

 

Take a fridge thermometer and take the wire and end out to the front of the wing mirror and tape it there and watch the temperature as you drive along.

I know how cold my exposed skin feels as i go downhill at 35 mph, but that is not the same as the temp metal, glass or plastic feels or actually is.

 

Edited 8 March, 20197 yr by Skoffski

Thermometer probes can't evaporate, screenwash can.  Look up 'latent heat of evaporation'.

Not 'wind chill' though. 

Just working like refrigeration.

Same effect though.

20 minutes ago, Skoffski said:

What happens does it get blast frozen?

Explanation of wind chill from Wikipedia - A surface loses heat through conduction, evaporation, convection, and radiation.[1] The rate of convection depends on both the difference in temperature between the surface and the fluid surrounding it and the velocity of that fluid with respect to the surface. As convection from a warm surface heats the air around it, an insulating boundary layer of warm air forms against the surface. Moving air disrupts this boundary layer, or epiclimate, allowing for cooler air to replace the warm air against the surface. The faster the wind speed, the more readily the surface cools.

 

Is that it then, 

it is -5*oC Ambient Air temp and -8*oC ground temp and the Screen is cold as the cars interior is the temp it has been from the car starting & no heated screen

and you spray the Windscreen wash which is still liquid as you go along at 30 mph.?

& the windscreen wash freezes on the screen even though it is supposedly good for -23*oC?

 

Amazeballs.

Edited 8 March, 20197 yr by Skoffski

Stuff also evaporates more readily if you move the vapour on from the immediate surface surroundings.  The faster you move it, the easier the next bit can evaporate.

As stuff evaporates, it cools what's left behind.  Have you lived your whole life without once blowing across a spoon full of too-hot soup?

Edited 8 March, 20197 yr by Wino

Why in a desert when very hot, not cold & you had Skin Water bottles and pour water on the outside to cool the water.

Its all like in real life.

Or you put a cloth on your head and wet it.

 Latent heat of evaporation is all I have to say.

Everyone has google, and some remembers science class.

Plus your windscreen can be colder than the air temp.

Just now, Skoffski said:

Everyone has google, and some remembers science class.

 

Oh you know how to hit below the belt, ski!

 

18 minutes ago, Aspman said:

Plus your windscreen can be colder than the air temp.

 

Turn the aircon off then! 

 

For the benefit of our Scottish members, this was an attempt at humour.....

Edited 8 March, 20197 yr by xman

Exactly.

But then it is off at the temps we are discussing or not.

12 minutes ago, Skoffski said:

Its all like in real life.

Or you put a cloth on your head and wet it.

Yeah, just like my neighbours.

 

11 minutes ago, Skoffski said:

Exactly.

But then it is off at the temps we are discussing or not.

 

Everyone has google, and some remembers science class. 

 

Some seem to have never even had hot soup.

Plenty have a slush puppy.

Hot soup is not Air, conductivity and all that jazz.  Solids, liquids and gasses. & the transition from solids, to liquid to gas or back.

 

 

Just like spaying H20 by fan into the cold air.

just the washer fluids freezing point is different and you are spraying onto a surface.

 

 

Edited 8 March, 20197 yr by Skoffski

You do talk some sense. But not on this subject.