Window film, what's your impression. Does it make a difference? - Page 2

 So are you saying the window film broke the glass; that the film shrinking
and expanding put too much pressure on the glass?

  On Sat, 6 Nov 2010 17:27:23 -0700, "ghelf"


 No, the rejected heat from the film mounted on the inner glass
cracked the outer glass. There was likely a minor stress/chip at the
edge of the glass that broke - which may have caused the glass to
greak in the next couple of years - but the glass had lasted about 2
years without the film, and only a matter of hours after the film was
installed.

Apparently NOT an un-common occurrence.

 Perhaps scratches during the pane scrubbing procedure played a part with the
heat sensitivity.

Commercial galss should be tempered,also. Some residential may not be. I
believe patio doors are.


clare@snyder.on.ca> wrote in message
 No, the rejected heat from the film mounted on the inner glass
cracked the outer glass. There was likely a minor stress/chip at the
edge of the glass that broke - which may have caused the glass to
greak in the next couple of years - but the glass had lasted about 2
years without the film, and only a matter of hours after the film was
installed.

Apparently NOT an un-common occurrence.


On Sat, 6 Nov 2010 17:27:23 -0700, "ghelf"

 wrote:


moveable glass like doors must be tempered. Store-front and commercial
glass generally is not required to be tempered, and no, there were NO
scratches from preparation. Tiny little nicks on the edge of the
glass, which is generally not edge polished when thermal units are
assembled, created just enough of a stress rizer to cause the glass to
crack when it and the airspace between the glass was heated by the
heat energy reflected off the film on the inner layer of glass. It was
NOT the coated glass that broke, but the uncoated outer pane.

 On Sun, 07 Nov 2010 00:09:05 -0400, clare@snyder.on.ca wrote:


Snipped from link below:

Will Window Films Cause Glass To Break?

Glass breaks when stressed.  There are five types of stress which may
cause glass breakage:  

1.  Thermal Stress--from absorption of solar radiation.

2.  Tensile Stress--from the weight of the glass itself.

3.  Mechanical Flexing Stress--from wind.

4.  Impact Stress--from flying objects, hail, baseballs.

5.  Twisting Stress--from building or window frame sagging or
settling.

The first type, thermal stress, is the only one which film may affect.
The use of window films will increase the thermal stress on sunlit
glass. However, there are also other factors which will increase
thermal stress such as: partial shading of windows from overhangs,
tightly fitting drapes or blinds, signs or decals on windows, heating
and cooling vents directed at glass. In addition, different types of
glass (annealed versus tempered, clear versus tinted) have different
solar absorption rates and will withstand different degrees of thermal
stress.

The window film manufacturers have recommended film-to-glass tables
for use by factory-trained dealer installers. If a consumer is ever in
doubt, he/she should request a copy of such guidelines. Listed are
some glass types or conditions where the use of a solar control (not
clear safety) type of window film is not recommended without extreme
caution.  

SINGLE PANE GLASS LARGER THAN 100 SQUARE FEET.  
DOUBLE PANE GLASS LARGER THAN 40 SQUARE FEET.  
CLEAR GLASS THICKER THAN 3/8 INCH.  
TINTED GLASS THICKER THAN 1/4 INCH.  
WINDOW FRAMING SYSTEMS OF CONCRETE, SOLID ALUMINUM, OR SOLID STEEL .
GLASS WHERE SEALANT OR GLAZING COMPOUND HAS HARDENED.
VISIBLY CHIPPED, CRACKED OR OTHERWISE DAMAGED GLASS.  
REFLECTIVE, WIRED, TEXTURED, OR PATTERNED GLASS.  
TRIPLE PANE GLASS.  
LAMINATED GLASS WINDOWS

http://www.iwfa.com/iwfa/Consumer_Info/qa.html