On 12 Jan 2006 02:54:42 -0800, wrote:


Windscreens aren't made out of the same glass as glasses are.
I've used hot water for years and a friend uses boiled water out of a
kettle.
You're not immersing a frozen windscreen into a tub of boiling water -
you're pouring a thin layer of hot water onto a cold windscreen so
there's not huge energy transfers going on.

Yeah, I recon that the layer of ice takes most of the thermal shock
away.

Anyhoo, if the hot water is prone to re-freezing it can't be heating
the glass very rapidly, can it?

sponix