On Wed, 30 May 2007 18:29:05 GMT, Lobster
wrote:

I ordered a pane of toughened glass about 1.5m tall by 0.5m wide, which
I collected today intending to fit it - it's for a fixed light adjacent
to a front door.

Anyway, I got the old glass out this evening, cleaned everything up,
applied putty to the rebate and picked up the new pane... I was holding
it vertically between fingers and thumbs, just lining it up with the
frame when suddenly - KAPOW!! without any warning or provocation the
whole pane exploded instantaneously in mid air, and landed in a heap of
tiny pieces all over my feet. It must have looked like a Tom and Jerry
cartoon; I was left there holding out my empty hands with a stunned look
on my face.

That's the way they go !

My wife had the exactly the same experience with a glass shelf out of
a 4 years old kitchen cabinet.


Clearly I need to have a discussion with the glass supplier tomorrow
morning. It seems to me that the pane was flawed in some way - was the
toughening process done wrong in some way - plausible? Is this sort of
thing common? I'm just envisaging the reaction of the supplier tomorrow
- if he refuses to play ball and tells me I bashed it or dropped it I
would like some knowledge at my fingertips!

It will have had a flaw in it, whether you notched it in transport or
handling or they did will be a moot point.


I'm also concerned at another level - had this spontaneous breakage
occurred an hour later the pane would have been in situ and the property
empty for the night, and therefore totally open to burglary.

Small to medium size panes of glass are not very secure. AIUI burglars
tend not break in via big panes of glass, too much noise.

And if the
glass is so fragile, WTF is the point of paying for it to be toughened?

It doesn't break into sharp dangerous shards.

As a result of the toughening process the surfaces of the glass are
held in tension, if a break occurs in the surface that tension rips it
apart as soon as the break in the surface reaches a critical size
(when the crack gains more energy from the surface tension by growing
than it takes to open the crack it will propagate out of control).

In a shop unit I rent the insurance company insisted I have just such
a glass panel protected with a metal grille.


Would appreciate any comments (before tomorrow!).

Not much help I fear. :-(

DG