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Discussion Starter #1
I wish I had taken a before and after picture of my windshield but, it had a bad, 3/8" wide scratch on the drivers side left by the wiper blade that extended the entire sweep of the wiper. Being the original Car-Lite windshield with no chips or cracks, I really wanted to try to preserve it. I decided to buy a small bag of Cerium Oxide glass polishing powder from Amazon. I already had a 1" round, hard felt buffing ball that came with a die grinding set. You mix the Cerium Oxide with water until you have a runny paste. I began buffing using my 20V Dewalt drill motor and after about an hour, the scratch was completely gone. I was quite amazed. The wide scratch was white and a real distraction while driving not to mention and eye sorer. Anyway, the stuff works and works very well. Just thought I would share.
 

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In your scenario you're lucky because usually by the time you polish out the imperfection, you polish-in some optical
qualities you DON'T want in a windshield....
 
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In your scenario you're lucky because usually by the time you polish out the imperfection, you polish-in some optical
qualities you DON'T want in a windshield....
Well, I haven't driven it in the sun yet because its cloudy today but, it seems OK looking through it from the inside.
 

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I know with a mirror finish in metal you have to buff out to around 4 or so inches around the scratch to prevent those issues, I’d assume glass is the same? Either way, I’m very interested because I too have the original glass and a ton of scratches I’d like cleaned up.
 

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Heres a good video on polishing glass:

 

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I had scratches on my windshield. Most were light but it seems the wipers had been operated with completely worn wiper blades. I polished the scratches out by hand and it took hours. Someone complimented me on the nice windshield at a show.
 

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I need to polish the rear window on my fastback. Maybe I'll try once I get it back home.
 

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If you can feel it with your fingernail, it's done- you won't get it out. Buffing and polishing the windshield glass will cause visual distortions and or possibly cracking the glass. Similarly, on tempered glass (back and sides) you not only may distort it, but any build up of heat in a small enough area can actually cause the glass to explode (shatter). Yes, I've been there...... it totally sucks! Any idea how hard it is to find a '61 Starliner back glass!?!
 

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Agree with above, don't even bother trying to buff it out. live with it or replace it.
It will distort and shade or discolor the glass. The clown that did my rear fastback window should be shot.
 

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It can be done to an extent, what gets me is you say after an hour? I guess you were able to keep it cool because Heat is the killer. I never heard about the explosions but I know you can melt the plastic whatever that makes it "safety glass," i guess the explosion comes after the melting from out-gassing.

I had kind of the same 2 wiper marks and used regular paint compounds on low then a quick buff with the wool pad for a few seconds at a time, step away for a while then repeat. Got about 80% of it out and all out of eyelines.

But really an hour?!?
 

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It can be done to an extent, what gets me is you say after an hour? I guess you were able to keep it cool because Heat is the killer. I never heard about the explosions but I know you can melt the plastic whatever that makes it "safety glass," i guess the explosion comes after the melting from out-gassing.

I had kind of the same 2 wiper marks and used regular paint compounds on low then a quick buff with the wool pad for a few seconds at a time, step away for a while then repeat. Got about 80% of it out and all out of eyelines.

But really an hour?!?
No the other poster was talking about tempered glass exploding (shattering into thousands of small pieces) due to heat, not the windshield safety glass. Heating glass locally can cause differential expansion that can cause float glass to crack and tempered glass to shatter. Tempered glass is funny stuff. Very strong until structure is broken. You will never see a piece of tempered glass with a crack in it like you will a safety glass windshield. It goes from a solid piece of glass to thousands of pieces in a fraction of a second.
 

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How to polish glass, and the answer is you really can't. Cerium oxide is only really effective on extremely superficial scratches. I spent hours buffing all the glass for my 67, and looked pretty good when it was all done. Once I installed them and the sunlight is hitting the glass just right you kind of realize you didn't really do much at all. It's tough to polish glass.
 
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Well, Ive been driving it for a few days now and there is no optical distortion. Im really pleased with the way it turned out and yes, it only took and hour to remove the scratches. I used a really hard felt buffer, kept it wet, which probably kept the heat down. The process does make a mess though. Do it at your own risk. I really had nothing to lose.
 

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Interesting that the car glass doesn’t take well to polishing. Telescope mirrors are polished all the time. I have a Taurus that doesn’t have any scratches, but has micro pits that glare at night. I have been thinking about trying to polish it. Other option is to to start driving gravel roads until a rock hits it and I can get the insurance to replace it!
 

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Fitch...thanks for sharing information.

I used fine rubbing compound for paint to do same thing years ago (by hand). My windshield is pitted...still is. It did improve the surface to the point that it really helped visibility in the rain. And then put Rain-x afterwards. I can drive without wipers running and see. Not perfect but huge improvement compared to when I purchased the car.
 

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Interesting that the car glass doesn’t take well to polishing. Telescope mirrors are polished all the time. I have a Taurus that doesn’t have any scratches, but has micro pits that glare at night. I have been thinking about trying to polish it. Other option is to to start driving gravel roads until a rock hits it and I can get the insurance to replace it!
It probably has to do with automotive glass being tempered and much harder than glass used on telescope and microscope lenses.
 
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