On 18/07/2014 14:04, Dave Liquorice wrote:
It's funny stuff toughed glass, it's understress all the time and
when it goes it goes. The trigger can be pretty small, a nice sharp
automatic centre punch can do it. But I've also witnessed a Special
Effects guy having quite some difficulty shattering a toughed car
windscreen. He started very cautious with gentle taps from a small
hammer and cold chisel, end up with a lump hammer and really giving
it some...

That sounds more like a laminated screen, which is often 2 sheets of
toughened glass with a sheet of plastic laminated in the middle.

--
Tciao for Now!

John.