An odd windshield question.

[Altair]

Hello everyone, I'm new so I hope I am posting this in the correct section.

 

I have a new (new as of December) 2006 Scion xB. The question is that in the cold weather when you turn the engine on and the heater turns on and for a few seconds the windshield fogs up, I can see at least 4 perfect cirlces on the windshield perfectly spaced apart close to the middle. There may or may not be more, it is hard to see them as they only appear for a couple seconds. I was wondering if anyone knows what these could be? Theres nothing that would have been placed on the windsheild (its much too steep anyway). They are ~3 inches in diameter. The only theory I have is that it is the suction cups used in the factory to move it into place.

 

I know this is a pretty odd question but I am just curious and was hoping someone might have some insight.

 

Thanks,

-altair

[reverse]

Shot in the dark....

 

Car glass is not normal.

 

It is both laminated and tinted.

 

The lamination is: glass, plastic, glass.

 

You may be seeing an anomaly in the lamination process.

 

or maybe some artifact from the tempering process.

 

 

I think that there is something there, but it is not visible under normal conditions and reveals itself only under evaporation .

[Altair]

Shot in the dark....

 

Car glass is not normal.

 

It is both laminated and tinted.

 

The lamination is: glass' date=' plastic, glass.

 

You may be seeing an anomaly in the lamination process.

 

or maybe some artifact from the tempering process.

 

 

I think that there is something there, but it is not visible under normal conditions and reveals itself only under evaporation .[/quote']

 

Thanks, that makes sense, and also I had already come to the conclusion that it was only visible under evaporation, mainly because thats the only time I could see it. (You'll have to forgive me, I'm a smart ass)

[Phi for All]

Suction cups moving your windshield into place would be attached on the outside, and the fog from your heater is forming on the inside. The circles may have been from manufacturer's information stickers which were removed either at the factory or the dealership.

 

Have you tried cleaning the inside of the windshield with ammonia or vinegar? There could be some kind of film caused by off-gassing from your carpet or vinyl dashboard. Perhaps the film formed before the stickers were removed and now you see it when it fogs up.

[sunspot]

The fogging is due to tiny water droplets forming on the cold surface. This high surface tension situation is assisted by something on the surface. The washing suggestions should remove the film that is causing the problem. Fogging is a problem if someone smokes in their car. The cigarette smoke will cause the same surface tension problem. One can buy anti-fog spray that is used for eyeglasses. There is also some for windshields.

 

Speaking of surface tension, years ago a friend of mine had to drive somewhere in the rain, on a day that his windshield wipers suddenly went on the blink. Because he was so determined to go, I sprayed some clear silicone spray on his windshield. This increases the exterior surface tension causing water to bead and blow away at highway speeds. It only lasted for a few hours with his field of vision getting smaller and smaller maybe due to the way the rain water/road spray was flowing along the windshield and scrubbing off or altering the surface tension of the silicone.

[reverse]

Thanks, that makes sense, and also I had already come to the conclusion that it was only visible under evaporation, mainly because thats the only time I could see it. (You'll have to forgive me, I'm a smart ass)

 

Ok then cerebral cheeks, what are the perquisites for evaporation to occur?

 

All of them mind.

[Nevermore]

Well, it's not a design thing. I have a scion xb and don't have the same problem. Whatever this is, it's specific to your car.

[reverse]

I had a slightly tinted windshield put in a car once...

 

With one particular pair of sunglasses only, you could see a snake type shape in the middle of the screen.

 

It was something to do with the alignment of the glass domains due to tempering.

 

go figure.

[Externet]

Hi.

The fog deposited on the windshield is condensed vapor from humid carpets caused by wet shoes entering the vehicle, a wet umbrella, a leak in the heater core or poorly sealed door/window and blown towards the cold glass at several duct points.

Miguel