xa0s
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Registered: 4th Mar 08
Location: Dartford, Kent Car: Turbo'd Fabia vRS
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I've been told not to do this but my mum poured boiling water over her car windscreen time and time again for years whenever it got iced up with no issues at all. I've been running late a few times this week and poured it over mine with no issues either, does it depend on the type of windscreen or is it a slow process that weakens the glass gradually or something?
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Piér
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Registered: 4th Jan 10
Location: Gloucestershire
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When glass is frozen and then gets hot water poured on it its prone to smashing as the sudden increase in temperature causes the glass to expand/contract which makes it crack.
Water expands when it freezes, thats why when you put a ice cube tray in the freezer you never fill the cubes to the top 
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Piér
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Registered: 4th Jan 10
Location: Gloucestershire
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Take this for example...
Say you have a glass in the kitchen cupboard that you don't mind smashing. Put it in the freezer for a few hours or overnight and in the morning pour some boiling water into the sink with the plug in and then put the glass in, if it smashes there is your answer.
I have heard of windscreens cracking but never seen it so its upto you whether you risk doing it. I have to get up at 4AM for work and I leave myself a little more time so I can warm the car up and defrost it normally
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Ste
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Registered: 5th Mar 03
Location: Taif, Saudi Arabia
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It is mainly due to the fact windscreens are made from two sheets of glass laminated together with a plastic sheet in-between them. When you heat one sheet up a lot faster than the other, thermal expansion puts pressure on the glass where they are bonded together. If there are any weak points like stone chips a crack can propagate and wreck the screen. It's a risk and isn't really the most efficient way of defrosting the glass as the water will re-freeze anyway. Just don't be a cheapskate and buy some de-icer.
I would rather lose by a mile because i built my own car, than win by an inch because someone else built it for me.
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Mertin
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Registered: 12th Oct 05
Location: Scotland
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Alot of materials sill break if they are subject to shock changes in temperature. And glass isnt the strongest of materials so i wouldnt risk it myself for the sake of 5 mins and a tin of deicer
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Daniel_Corsa
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Registered: 21st Apr 04
Location: Wigton, Cumbria
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Just use lukewarm water, that's what I always do, doesn't need to be boiling to clear the windscreen!
April '06' Corsasport Feature Car  | Aug '08' Total Vauxhall Feature Car | Spring '09' Fast Car Feature Car
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oceansoul
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Registered: 19th Jun 06
Location: Sunbury, Surrey
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quote:
Originally posted by Daniel_Corsa
Just use lukewarm water, that's what I always do, doesn't need to be boiling to clear the windscreen!
Even water at room temp will do
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pow
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Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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Yup, when I'm running late I just fill a coke bottle up with warm water out th tap!
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baza31
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Registered: 19th Apr 03
Location: yorkshire
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quote:
Originally posted by pow
Yup, when I'm running late I just fill a coke bottle up with warm water out th tap!
same
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nathy_87
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Registered: 14th Aug 08
Location: West Mids. Drives: Škoda Fabia VRS 5J
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I boil the kettle open the lid a bit and leave it for a few minutes then pour it over never had any problems.
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LeeM
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Registered: 26th Sep 05
Location: Liverpool
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Lukewarm does it, may not be hot but it's still warmer than ice! I cringe driving down the road seeing people with freshly boiled kettles
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andys sxi
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Registered: 19th Jan 06
Location: Chester Drives:Scirocco tdi bluemotion
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quote:
Originally posted by 5dr corsa-3dr_polo
I boil the kettle open the lid a bit and leave it for a few minutes then pour it over never had any problems.
Why don't you half boil it then haha
April 08 feature car
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AndyCorsaSport
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Registered: 12th Feb 06
Location: Horsforth, West Yorkshire
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My mate once had a 330 BMW hire car, he sacked the heaters on full wack on a cold day and that cracked the screen 
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Robo C20Let
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Registered: 22nd Feb 10
Location: Somewhere inside your mom !!!
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no one got any pics lol
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sc0ott
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Registered: 16th Feb 09
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if you dont have tap water then piss on it.
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A2H GO
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Registered: 14th Sep 04
Location: Stoke
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Ive been doing this for the past week or so but as said, it just freezes up again anyway and takes even longer to defrost as the scraper just slides straight over the ice. Only trouble is nowadays deicer is so weak it wont defrost shit. Tried both Tesco and Halfords, used half a can one morning and still couldnt see a thing for ice.
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nathy_87
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Registered: 14th Aug 08
Location: West Mids. Drives: Škoda Fabia VRS 5J
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quote:
Originally posted by andys sxi
quote:
Originally posted by 5dr corsa-3dr_polo
I boil the kettle open the lid a bit and leave it for a few minutes then pour it over never had any problems.
Why don't you half boil it then haha
because I won't be able to do the whole car. 
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3CorsaMeal
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Registered: 11th Apr 02
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i just hold a neighbours cat onto the windscreen for a while, the struggling and the heat it generates melts the ice quite well, but you are left with a bit of a hairy windscreen
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alan-g-w
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Registered: 9th Nov 07
Location: Glasgow
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Lukewarm water is the answer, just stick the wipers on so it doesn't freeze up. Side windows, even if they do freeze you can still see through them.
[Edited on 07-12-2010 by alan-g-w]
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John
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Registered: 30th Jun 03
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Or leave the car on to heat up for 5 or 10 mins.
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3CorsaMeal
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Registered: 11th Apr 02
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damages the cat
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John
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Registered: 30th Jun 03
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Cat should be in the bin, not sitting on your car.
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sc0ott
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Registered: 16th Feb 09
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quote:
Originally posted by 5dr corsa-3dr_polo
quote:
Originally posted by andys sxi
quote:
Originally posted by 5dr corsa-3dr_polo
I boil the kettle open the lid a bit and leave it for a few minutes then pour it over never had any problems.
Why don't you half boil it then haha
because I won't be able to do the whole car.
i think he means switch the kettle off roughly half way through the boiling process and not half fill it.
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sc0ott
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Registered: 16th Feb 09
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quote:
Originally posted by 3CorsaMeal
i just hold a neighbours cat onto the windscreen for a while, the struggling and the heat it generates melts the ice quite well, but you are left with a bit of a hairy windscreen
try getting her to shave her pussy next time.
not sure what age kids start puberty at these days though so its worth asking
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karisma_corsa
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Registered: 19th Nov 06
Location: sleaford, lincs
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put a sheet over the screen at night. Works for me
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