quattro Digest, Vol 9, Issue 59 - Re: removing rear quarter window from part-out Avant

[Larry C Leung]

FYI,

Tempered Safety glass is actually stressed in the tempering process. The
stress
is supposed to be even throughout the matrix, hence it will break into
little unsharp
pieces (the safety part) as opposed to sharp shards. The stress means
every little
bump decreases the finite life of the glass. Since the glass is stressed,
it will 
"explode" when it fails, but it explodes in relatively safe shapeless
pieces. Without
this pre-stress, the glass will fail in the traditional manner of window
glass, which 
isn't good. BTW, this is precisely why many a hatched vehicle ends up
with a
shattered rear window later in it's life, this has happened to a
colleagues Isuzu
Rodeo, and my friend's '93 100CSQA. So, if you have a hatched vehicle,
and
it's getting on in years, and you still have full glass coverage, keep
the coverage.

LL - NY


> ------------------------------
> 
> Date: Thu, 22 Jul 2004 10:43:20 -0400
> From: Brett Dikeman <brett at cloud9.net>
> Subject: Re: removing rear quarter window from part-out Avant
> To: Ben Swann <benswann at comcast.net>, "Craig Gary" <cgary at psu.edu>
> Cc: Ben Swann <benswann at comcast.net>, quattro at audifans.com,
>         200q20v at audifans.com
> Message-ID: <a05200f09bd24e3058934@[192.168.1.2]>
> Content-Type: text/plain; charset="us-ascii" ; format="flowed"
> 
> At 11:13 PM -0400 7/21/04, Ben Swann wrote:
>---------------snip-------------------------- 
> My first thought is that as the glass is pulled off the sealant, the 
> 
> area pulled off the sealant had more and more of a lever action on 
> the part that was still attached.  Another possibility is that the 
> glass was scored or hit during its lifetime in the car (ie by 
> something in the back sliding around etc).
> 
> Kind of surprising- I would have thought the stuff would be safety 
> glass and hence crack, but not "explode".
> 
> Brett