DJC wrote:
On 22/12/17 14:34, ARW wrote:
De-icer these days only seems to work when it's above minus 1 deg
regardless of what it says on the tin.
During the recent cold spell I spayed de-icer on the windscreen, which
promptly froze making things worse. I wasn't below -2C.

The air temperature may be above -2 but how cold was the windscreen?

The problem with windscreens is that they face the sky. On a clear
night heat radiates from the glass into space, and that coming back is
minimal as space is about -270C. The screen can't get too cold as it
will absorb heat from the air, but it can be well below the air
temperature.

Was it an aerosol or spray bottle? I find the aerosol de-icers useless -
the aerosol cools the de-icer (which cools the windscreen) so much that
it adds ice to the windscreen rather than removing it. The spray
bottles don't have this issue as there's no propellant to cool the
spray.

Mike

On Friday, 22 December 2017 20:05:03 UTC, newshound wrote:
On 22/12/2017 14:09, Caecilius wrote:
On Fri, 22 Dec 2017 13:16:31 +0000, Max Demian
wrote:

On 22/12/2017 13:03, Caecilius wrote:
On Fri, 22 Dec 2017 12:17:07 +0000, Vortex13
wrote:

Used undiluted it claims protection to -20C

50% dilution claims protection to -7.5C

How does that work then?

It's probably a mixture of alcohol and water. The alcohol is probably
methanol, as that's the cheapest alcohol available.

I would have thought that methylated spirit is cheaper (ethanol with
around 7.5% methanol). (I used to add meths to my washer bottle, which
coloured the plastic purple.)

I think methanol is the cheapest at the industrial level, but I might
be wrong.

I wouldn't use meths myself, as I don't like the pyridine smell, and I
suspect that it would rot the windscreen wiper blades.

That's only in the purple "domestic" stuff, proper "Industrial Meths"
doesn't have it.

The purple colour is caused by stuff added to it to give it a bad taste and also not be mistaken for water. Discourages people from drinking it.

On 31/12/2017 09:28, harry wrote:
On Friday, 22 December 2017 20:05:03 UTC, newshound wrote:
On 22/12/2017 14:09, Caecilius wrote:
On Fri, 22 Dec 2017 13:16:31 +0000, Max Demian
wrote:

On 22/12/2017 13:03, Caecilius wrote:
On Fri, 22 Dec 2017 12:17:07 +0000, Vortex13
wrote:

Used undiluted it claims protection to -20C

50% dilution claims protection to -7.5C

How does that work then?

It's probably a mixture of alcohol and water. The alcohol is probably
methanol, as that's the cheapest alcohol available.

I would have thought that methylated spirit is cheaper (ethanol with
around 7.5% methanol). (I used to add meths to my washer bottle, which
coloured the plastic purple.)

I think methanol is the cheapest at the industrial level, but I might
be wrong.

I wouldn't use meths myself, as I don't like the pyridine smell, and I
suspect that it would rot the windscreen wiper blades.

That's only in the purple "domestic" stuff, proper "Industrial Meths"
doesn't have it.

The purple colour is caused by stuff added to it to give it a bad taste and also not be mistaken for water. Discourages people from drinking it.

Actually the stuff that makes it nasty to drink is usually pyridine,
which is colourless. The purple dye is something different.

--
Max Demian

On 31/12/17 12:22, Max Demian wrote:
On 31/12/2017 09:28, harry wrote:
On Friday, 22 December 2017 20:05:03 UTC, newshoundÂ* wrote:
On 22/12/2017 14:09, Caecilius wrote:
On Fri, 22 Dec 2017 13:16:31 +0000, Max Demian
wrote:

On 22/12/2017 13:03, Caecilius wrote:
On Fri, 22 Dec 2017 12:17:07 +0000, Vortex13

wrote:

Used undiluted it claims protectionÂ* to -20C

50% dilution claims protection to -7.5C

How does that work then?

It's probably a mixture of alcohol and water.Â* The alcohol is
probably
methanol, as that's the cheapest alcohol available.

I would have thought that methylated spirit is cheaper (ethanol with
around 7.5% methanol). (I used to add meths to my washer bottle, which
coloured the plastic purple.)

I think methanol is the cheapest at the industrial level, but I might
be wrong.

I wouldn't use meths myself, as I don't like the pyridine smell, and I
suspect that it would rot the windscreen wiper blades.

That's only in the purple "domestic" stuff, proper "Industrial Meths"
doesn't have it.

The purple colour is caused by stuff added to it to give it a bad
taste and also not be mistaken for water.Â* Discourages people from
drinking it.

Actually the stuff that makes it nasty to drink is usually pyridine,
which is colourless. The purple dye is something different.


N-(4-(bis(4-(dimethylamino)phenyl)methylene)cyclohexa-2,5-dien-1-ylidene)methanaminium
chloride)

Apparently.



--
"Women actually are capable of being far more than the feminists will
let them."