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Old 03-04-2010, 02:10 PM   #146 (permalink)
Christ
Moderate your Moderation.
 
Join Date: Nov 2008
Location: Troy, Pa.
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Quote:
Originally Posted by Bicycle Bob View Post
Defrosting conductors can be scraped off with a razor.

Many areas require laminated glass for the windshield, while tempered is used for rear and side windows.
Tempered glass is much like tempered steel - It gets quenched while hot, although the glass requires more support. It is usually done with blasts of air, and the pattern of the jets used can be seen in polarized light. The process causes the glass to shrink first on the surface, so that you wind up with the surface in compression and the interior in tension. Since cracks start from the surface, they are held shut instead of progressing, up to a much higher force than usual. However, when one does get going, it sets off the whole piece, and the internal stresses turn it all to small, harmless pieces. It is interesting, when carrying a single patio door panel, to touch it to a bit of concrete patio. You hear a bang, and suddenly, the weight is gone.
I just did this a few weeks ago, actually. The pile of glass was just large enough to make me think that some of the glass must have come from the Nexxus or something, because it seems that the tempered glass spreads everywhere once it breaks.
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