Why Do Car Windows Have Black Rims and Small Black Dots?

Discussion in 'The Champagne Room' started by SRT-Tom, Jul 31, 2020.

  1. SRT-Tom

    SRT-Tom Well-Known Member Super Moderator Article Writer

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    Did you ever wonder why cars and buses have black rims and a pattern of little black dots on the edges of their windows?

    Those black dots on windshields and windows and the black rims that surround them do have a reason for being there (other than decoration). It has to do with how car windows are made- from the 1950s and ’60s onward, car manufacturers started to use an adhesive to hold car windows in place, rather than metal trim.

    This adhesive got the job done, but it wasn’t very aesthetically pleasing. Enter the black rims that you see around car windows, called "frits." The frits (and the dots that border them) are made from ceramic paint. The frits are there to hide the rather unsightly, but very important, adhesive from view. Also, since these painted rims are baked into the window, they are all but indestructible. They hold the glue in place, which in turn holds the windows in place.

    As for the dots, they are there to make an aesthetically pleasing transition from the thick black lines to the transparency of the window. The dots aren’t randomly placed; they are positioned in what’s known as a “halftone pattern,” getting smaller and farther apart as the black recedes. This pattern is less jarring to the eye than opaque black paint juxtaposed with transparent glass. However, even the dots aren’t just there for decoration. Their other purpose, besides the visual effect, is to provide temperature control. To get the glass of windows and windshields to be bent the way it is, the glass is heated up. The black-painted glass heats up faster than the rest of the window. The dots are there to distribute the heat a little more evenly, which prevents the windshield from warping in the heat.
     
  2. Katshot

    Katshot Full Access Member

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    Ok, you're right that the black rim is called the "frit" and yes it does help hide the adhesive but there's more to it than that. Not sure why you're referencing the 50's and 60's in this article because the frit has only been used in recent years. I can't say specifically when the frit became a thing but as I recall windshields started getting "glued" in probably back in the 90's.
    Prior to that windshields were not actually a structural component as they are now. To be honest, my guess is, they started using urethane adhesive on windshields as more vehicles switched from body-on-frame construction to unibody. Unibody cars flex quite a bit and having the glass (all stationary glass, not just windshields) bonded to the metal (or plastic) structure of the vehicle greatly increased overall structural integrity. As they started this, moldings also got smaller for multiple reasons. They didn't need to help retain the glass. They needed to be more aerodynamic, and there's always cost, weight etc, etc. The notion that the frit was conceived as a way to hide the adhesive is quite possible but as I recall, the main reason for it is to increase the bond strength between the glass and the vehicle structure.
     
    Last edited: Jul 31, 2020
  3. B5blueRT

    B5blueRT Full Access Member

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    I'm just glad I have one on my car... don't like the taste of bugs. :eek:
     
  4. TRCM

    TRCM Full Access Member

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    I want to replace the windshield in my SRT to get rid of the many tiny chips in it.......but am afraid I won't be able to get a replacement with the car in the lower drivers corner.
     
  5. 70-426_10-SRT

    70-426_10-SRT B&E body lover

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    BikerLove.jpg
     
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  6. Katshot

    Katshot Full Access Member

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    57_436e1bd3-7082-48e2-a72a-779eff1ae56d_1200x1200.jpg OEM03_309279954_AR_-1_0.jpg
    As long as it's a Mopar windshield, it should have it. My Jeep Wrangler has little Wranglers on it too! That's one way to know for certain if someone replaced the windshield before you bought the car. No cool little graphics around the rim, it's an aftermarket windshield.
     
  7. IntimidatorRT

    IntimidatorRT Well-Known Member Staff Member Super Moderator

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    those little logos were little easter eggs as they called them..... some of them got them got and some didn't. it was all the luck of the draw with those. my wife had a 2015 Cherokee and it has some of those, even the MOWAB map under the passenger seat.... but her 2017 Grand Cherokee didn't. Same was it goes for the dodges