…why, in the past decade or so, car windows and windshields have started to have opaque black margins, rather than being clear all the way to the edges as they used to be. Is this stylistic or structural? Does anyone have a clue? How would one go about researching the answer to this question? Anyone have any contacts in the auto industry to whom this query could be directed?
Eliot,
Here’s an explanation on an internet message board:
What you are refering to is called a frit. It is the black band around modern auto glass. It’s purpose is more than aesthetic, it also protects the urethane sealant that is used in modern window systems from being degraded by the UV in sunlight. Any good glass supplier can get you the material to create one with. It is the same material that you use to prime the pinch weld before applying the adhesive. You mask up the rear of the window to leave just the area that you want to apply the material to and then you just apply the primer. It is usually supplied in a can with a dauber on the lid. Just run the dauber around the unmasked area.
See http://www.chevelles.com/forums/showpost.php?s=355cdfdccb4b93f24992ba33d67b3a82&p=2656510&postcount=3
Googling ‘frit auto windows’ seems to confirm this. For instance, http://www.wikihow.com/Replace-Your-Automobile-Windshield
Prepare the glass with a primer specially matched to the urethane adhesive. The purpose of the primer is to open the molecules of the frit band (the black band around the perimeter of the windshield) this is done to prepare the glass to accept the molecules of the urethane. If your installer is in a hurry, ignorant or just does not care if your windshield pops out he will skip this step. After the glass is activated, the molding is attached to the glass and the urethane is next.
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And that’s why I’ve decided to stick with my 99 Subaru Outback wagon rather than replace it with a new car. The band(s) limit visibility too much.
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