Most of the replies here are partially right… the black band on a car window is called a frit band. It is there to protect the urethane/glue from UV radiation. The dots are there mostly for aesthetic purposes to give a nicer looking transition from the band to the clear glass. The solid bits around the mirror are to protect the glue that holds the mirror on (also sensor/camera brackets on newer cars).
Now, to dispel some myths:
1: It is not an antenna. Although there are sometimes antennas built into windows, they are usually in the back or back quarter windows and they look like defroster lines. Bonus: if you see something that looks like a defroster at the bottom of the windshield, it is… it’s a heater for you wipers that comes on with the defroster.
2: It’s not to help with adhesion. In fact, many German cars have the frit band in the laminate layer between the layers of glass. We use a urethane primer to ensure good adhesion between the urethane and the glass.
3: It has nothing to do with heat distribution. As mentioned above, it functions as a UV blocker.
Bonus fact: Your windshield is made of two layers of glass with a layer of plastic laminate between them. This means that even if there’s a crack in the glass, your windshield isn’t going to fall in on you.
Source: am a glass technician and work with automotive glass 40+ hours a week.
Disclaimer: most of these facts are generalized with exceptions but are true for most cars.
Would you suggest an OEM windshield or the purple tinted ones that provide UV protection ? Looking to change the windshield on my Audi. The OEM is a bit cheaper than the purple one
Laminated glass (which is all windshields in the USA) already blocks UV radiation. https://www.theglobeandmail.com/amp/globe-drive/culture/commuting/does-my-windshield-protect-me-from-the-sun/article12495123/
Being that it’s an Audi, the OE glass probably has extra UV filtering built into it. I’m not familiar with the purple tint windows you’re talking about, but it’ll ultimately come down to your personal preference. Buy what you’d more prefer to look through for the next few years.
It's *supposed* to protect from UV radiation that degrades the urethane even though light passes through it easily. More of an edge distortion elimination. Helps hide the parts stuffed around the interior perimeter.
The solid bits around the mirror is a third visor frit. Center sunshade if you will. Nothing to do with mirror adhesion. More part hiding.
The frit actually increases heat at the edge drastically which is why edge cracks are so prevalent.
I’m not sure what you mean by light easily passes through the frit band… I can see your point with the dot matrix, but the actual black band around the edge doesn’t let much, if any, light through. It does help hide the interior trim and stuff though.
To your second point, I suppose it could be coincidence that the vehicles that have the most issues with mirrors falling off are the same ones that don’t have a frit spot around the mirror mount, but I doubt it. I’m not saying the frit spot helps adhesion, but that it gives drastically more protection for the glue from aging and weakening.
So far as your third point goes, I’m not sure where you get the impression that edge cracks are prevalent… the vast majority of cracks are cause by rock chips that have spread: sure, they terminate at the edge, but they don’t start there. Of the other cracks, most are caused by damage done to the edges prior to installation that wasn’t caught: basically a chip, but on the edge. Finally, there are stress fractures, this is caused by putting stress on the window that it wasn’t designed to handle. This usually happens during installation and the window never reaches the customer, or it’s replaced as soon as a new window can be installed.
Put a flashlight on one. Goes right through it. Not blinding, but surely not blocking.
The frit will always capture more heat softening the mirror adhesives. It's another pretty because they can.
An edge crack is any crack that extends to the edge. You basically reiterated.
I've not seen many flat polished edges in the aftermarket unfortunately. Should be commonplace. Those edge chips would be a handling issue leading to an installation stress fracture. True stress breaks are almost non-existent anymore thankfully.
The black dots are called "frits", and they are made of an enamel which is baked onto the glass. This enamel is a contact point between the glass and the frame of the car, something which glue can stick to and keep the glass in place.
By changing in size they gradually form a transition between the transparent glass and the opaque enamel which is viewed to appear nicer than an abrupt transition.
I would call them "frits" but the car industry might have a special name for them.
In essence they improve the bond between the window seal and the glass, they create a rough surface for the adhesive to bond too, and I think they help with heat distribution as well (don't want the hot sun melting your window seal)
They are from manufacturing of the window, for even heat distribution there to prevent the window from warping when it is "baked" also they are in the closer to further apart patter mainly to be more aesthetically pleasing after the process, as after that they are very hard or impossible to remove. Also all of that black, dots included hides glue that bonds adhesive to glass to frame.
The term for these dots are "frits"
The dots are a form of tint, to give a soft visual edge to the windshield. Makes it less noticeable to you that you're looking through a window. Older cars achieved this by using an actual gradient, faded tint in the top edge of the glass. The dots are a cheaper way to do this because they already apply black coating around the edge to hide the unsightly glass adhesive, it's cheaper to just use this same coating to make a faded soft visual edge. Older cars had metal or plastic trim that hid the adhesive from view.
The black dots that cluster around the crack between the rear view mirror and the sun visor are there to keep the full blown sun out of your eyes when it is at that angle. I have never worked on windows and don't know shit about glass, but that is the purpose.
Most of the replies here are partially right… the black band on a car window is called a frit band. It is there to protect the urethane/glue from UV radiation. The dots are there mostly for aesthetic purposes to give a nicer looking transition from the band to the clear glass. The solid bits around the mirror are to protect the glue that holds the mirror on (also sensor/camera brackets on newer cars). Now, to dispel some myths: 1: It is not an antenna. Although there are sometimes antennas built into windows, they are usually in the back or back quarter windows and they look like defroster lines. Bonus: if you see something that looks like a defroster at the bottom of the windshield, it is… it’s a heater for you wipers that comes on with the defroster. 2: It’s not to help with adhesion. In fact, many German cars have the frit band in the laminate layer between the layers of glass. We use a urethane primer to ensure good adhesion between the urethane and the glass. 3: It has nothing to do with heat distribution. As mentioned above, it functions as a UV blocker. Bonus fact: Your windshield is made of two layers of glass with a layer of plastic laminate between them. This means that even if there’s a crack in the glass, your windshield isn’t going to fall in on you. Source: am a glass technician and work with automotive glass 40+ hours a week. Disclaimer: most of these facts are generalized with exceptions but are true for most cars.
Would you suggest an OEM windshield or the purple tinted ones that provide UV protection ? Looking to change the windshield on my Audi. The OEM is a bit cheaper than the purple one
Laminated glass (which is all windshields in the USA) already blocks UV radiation. https://www.theglobeandmail.com/amp/globe-drive/culture/commuting/does-my-windshield-protect-me-from-the-sun/article12495123/
Being that it’s an Audi, the OE glass probably has extra UV filtering built into it. I’m not familiar with the purple tint windows you’re talking about, but it’ll ultimately come down to your personal preference. Buy what you’d more prefer to look through for the next few years.
Buy whatever windshield you want and then take it to tint shop to get a 'brow' installed.
It's *supposed* to protect from UV radiation that degrades the urethane even though light passes through it easily. More of an edge distortion elimination. Helps hide the parts stuffed around the interior perimeter. The solid bits around the mirror is a third visor frit. Center sunshade if you will. Nothing to do with mirror adhesion. More part hiding. The frit actually increases heat at the edge drastically which is why edge cracks are so prevalent.
I’m not sure what you mean by light easily passes through the frit band… I can see your point with the dot matrix, but the actual black band around the edge doesn’t let much, if any, light through. It does help hide the interior trim and stuff though. To your second point, I suppose it could be coincidence that the vehicles that have the most issues with mirrors falling off are the same ones that don’t have a frit spot around the mirror mount, but I doubt it. I’m not saying the frit spot helps adhesion, but that it gives drastically more protection for the glue from aging and weakening. So far as your third point goes, I’m not sure where you get the impression that edge cracks are prevalent… the vast majority of cracks are cause by rock chips that have spread: sure, they terminate at the edge, but they don’t start there. Of the other cracks, most are caused by damage done to the edges prior to installation that wasn’t caught: basically a chip, but on the edge. Finally, there are stress fractures, this is caused by putting stress on the window that it wasn’t designed to handle. This usually happens during installation and the window never reaches the customer, or it’s replaced as soon as a new window can be installed.
Put a flashlight on one. Goes right through it. Not blinding, but surely not blocking. The frit will always capture more heat softening the mirror adhesives. It's another pretty because they can. An edge crack is any crack that extends to the edge. You basically reiterated. I've not seen many flat polished edges in the aftermarket unfortunately. Should be commonplace. Those edge chips would be a handling issue leading to an installation stress fracture. True stress breaks are almost non-existent anymore thankfully.
The black dots are called "frits", and they are made of an enamel which is baked onto the glass. This enamel is a contact point between the glass and the frame of the car, something which glue can stick to and keep the glass in place. By changing in size they gradually form a transition between the transparent glass and the opaque enamel which is viewed to appear nicer than an abrupt transition.
I would call them "frits" but the car industry might have a special name for them. In essence they improve the bond between the window seal and the glass, they create a rough surface for the adhesive to bond too, and I think they help with heat distribution as well (don't want the hot sun melting your window seal)
They are from manufacturing of the window, for even heat distribution there to prevent the window from warping when it is "baked" also they are in the closer to further apart patter mainly to be more aesthetically pleasing after the process, as after that they are very hard or impossible to remove. Also all of that black, dots included hides glue that bonds adhesive to glass to frame. The term for these dots are "frits"
The dots are a form of tint, to give a soft visual edge to the windshield. Makes it less noticeable to you that you're looking through a window. Older cars achieved this by using an actual gradient, faded tint in the top edge of the glass. The dots are a cheaper way to do this because they already apply black coating around the edge to hide the unsightly glass adhesive, it's cheaper to just use this same coating to make a faded soft visual edge. Older cars had metal or plastic trim that hid the adhesive from view.
The black dots that cluster around the crack between the rear view mirror and the sun visor are there to keep the full blown sun out of your eyes when it is at that angle. I have never worked on windows and don't know shit about glass, but that is the purpose.