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Sun Feb 15, 2009 10:58 pm

Well, since there are over 200 oval windshield related topics I figured one more couldnt hurt, just thought some of you would be interested in the results of highway speed gravel truck debris vs. a factory Euro spec Tempered Windshield, after 13 October 1954 VW installed what they called windshields with a "vision area" in front of the drivers face which was tempered to remain in one piece while the rest of the windshield shattered into about one million pieces, the remaining clear section allowed you to safely get off the highway or slow down before the whole windshield fell out in your lap, also I suppose if your head was hitting the windshield in a major collision the round section in front of you would tend to stay in one piece as the rest of the windshield shattered around it as your head left the car ... obviously the Americans had different ideas about what kind of glass was safer, the Tempered glass was indeed stronger right up to the point of breakage and more resistant to scratches and minor rock damage, just wanted to post a photo of what happened to my original Tempered glass, the Serial number for the "vision area" start was -1-0730023 according to Progressive Refinements

Sun Feb 15, 2009 11:04 pm

That aughta buff out-----right??

Jody

Sun Feb 15, 2009 11:08 pm

-----but seriously, how could they get just that area tempered without some distortion or something around it when not shattered ?? Great Idea though, it worked !!!

Jody

Sun Feb 15, 2009 11:29 pm

I believe the Tempering was done with jets of gas flame and little blasts of cool air while the windshield was being made, it WAS actually possible to see the round area in reflections before it broke or at dusk while the sun was going down just right or if you were wearing polarized sunglasses you could see a rainbow effect around the vision area, I've only seen a few other cars here in the USA with the original late '54 Euro glass still in them but if you know what to look for you can always see the distinctive round rainbow effect in front of the driver, they are few and far between though

Mon Feb 16, 2009 12:32 am

That make sense!!

I have always wondered about why the area in front of my head is special, especially with sunglases on I can see the round area with "petrol-colours".
I know my car have been in accidents, so I thought someone once had hit the window hard, but you gave me the answer.

Thanks! :D

Mon Feb 16, 2009 11:32 pm

billmetric wrote: ...., it WAS actually possible to see the round area in reflections before it broke or at dusk while the sun was going down just right or if you were wearing polarized sunglasses you could see a rainbow effect around the vision area, I've only seen a few other cars here in the USA with the original late '54 Euro glass still in them but if you know what to look for you can always see the distinctive round rainbow effect in front of the driver, they are few and far between though

i have seen a couple cars with that rainbow circle in the windshield. never knew why

Tue Feb 17, 2009 7:50 am

I hit an aftermarket windshield with my head once..... knocked the whole thing out, landed between the hood handle and the bumper.....

Tue Feb 17, 2009 10:23 pm

billmetric wrote: ...., after 13 October 1954 VW installed what they called windshields with a "vision area" in front of the drivers face which was tempered to remain in one piece while the rest of the windshield shattered into about one million pieces, ...[/img]

What was the windshield before then? Tempered? Plain glass?

Wed Feb 18, 2009 8:52 am

Prior to 13 October 1954 on Euro spec cars the windshields were tempered uniformly overall causing complete loss of vision if a rock were to shatter the glass, due to the nature of tempered glass any rock which was big enough to crack the glass would cause the entire windshield to shatter into small pieces, a lot of the energy of the rock would be absorbed by the forceful shattering of the glass allowing the glass to remain in place but blocking any vision thru it

Wed Feb 18, 2009 10:04 am

Very interesting topic...................

I did not know about the euro-spec windshield having the vision area....
Is the "rainbow effect" not visable in that part of the window?

Wed Feb 18, 2009 10:43 am

billmetric wrote: a "vision area" in front of the drivers face which was tempered to remain in one piece while the rest of the windshield shattered into about one million pieces

Actually the whole windshield was tempered except for that small section. When plate glass breaks it shatters into large sharp pieces, tempering makes it explode into those small "harmless" pieces. Nothing like having a razor sharp flying glass disk, at throat level, come flying at you in a crash :shock:

Wed Feb 18, 2009 11:22 am

Was (is) that area less susceptible to scratches than the rest of the windshield ?? The front glass in my Mar'55 has no markings at all, do you think it has been replaced ?? All the rest of the windows are large SEKURIT.

Jody

Wed Feb 18, 2009 12:42 pm

I read in an old book (1956) that it also would work the other way around - if a rock hit the area in front of the driver, that area should break while the rest of the windscreen would remain clear... Book has a picture showing a guy looking out of the clear area in front of him... :)

Wed Feb 18, 2009 4:57 pm

the windshield in the photo was almost 50 years old when it broke and it was virtually scratch free, I didnt notice any differance in durability between the vison area and the rest of the glass,
the "rainbow effect" where you can see the tempering patern with polarized sunglasses was visable everywhere except in the center of the vision area, at the transition point there was an actual circular rainbow where you could see several color changes in rings around the circular area, I'm not sure what method of tempering was employed at the time but I dont think any part of a single pane of tempered glass could be called plate glass in itself, I would suspect that if a large enough rock hit the vision area without breaking, it would probably cave in the whole windshield as the rest of the glass crystalized around it, I would be interested in seeing that photo from the 1956 book, I remember seeing some promotional type photos from the day, that sounds similar,
as far as markings on the glass mine was extremely faint almost invisable, I'm sure I would have saved the logo area at the time it broke if I could have seen it, I'm thinking it was probably Duro-Glas or Sekurit but I really dont remember, I have a few old photos I took while driving before it broke, I will look thru them and see if I can make it out in any of them or at least jog my memory, I do remember that it was in the lower left corner FAINT, barely visable at all...

Thu Feb 19, 2009 12:54 am

I checked the original SEKURIT front window from a 51 split with polarized sunglasses, and there's no clear area in front of the driver as described. It appears the whole window is uniformly tempered.

Thu Feb 19, 2009 6:09 am

Was a popular option in the CA bay area. I see lots of rainbows on glass out there............. :wink:

Fri Aug 31, 2012 2:03 pm

My RHD Cabrio original windscreen...

Sat Sep 01, 2012 2:25 am

Most interesting - I'd noticed it on my spare screen as I put it in the loft and assumed it was a fault or stress marks - it's nice to know it's og and nothing wrong with it.

Dave

Sat Sep 01, 2012 2:51 am

RichOakley wrote: My RHD Cabrio original windscreen...

Nice car!
Reminds me of a friend who put the windscreen in the wrong way, and got the vision area on the right side, in a LHD. Did VW make own windscreen for RHD, or just turn the windscreen?

PS: Rich, I meet you at BC last year, we stayed at the same motel.

:D

Sat Sep 01, 2012 4:32 am

Kjell Roar wrote: RichOakley wrote: My RHD Cabrio original windscreen...

Nice car!
Reminds me of a friend who put the windscreen in the wrong way, and got the vision area on the right side, in a LHD. Did VW make own windscreen for RHD, or just turn the windscreen?

PS: Rich, I meet you at BC last year, we stayed at the same motel.

:D

I remember, it was nice to meet you. :)

I think it may be RHD-only. The 'VISURIT' logo is in the bottom (driver's side) corner.