Took 20 years off my windshield!!
 

I finally got around to trying to polish 20 years of wiper wear and streaks off of my windshield. I tried a polish supposedly designed to take it light to medium scratches. It had no effect. So, I turned to mother Google and learned about Cerium Oxide. I ordered a 1lb canister of it off of Amazon here - https://amzn.com/B007R69W9A

Then follow these directions on YouTube - https://youtu.be/JErQ72NH4jA

What an amazing difference...it is nearly new. I used an orbital buffer with a dense cotton polishing pad (for an angle grinder). I just mashed it between the glass and buffer. I buffed each side (passenger/driver) for about 10 minutes each.

Anyway hope this helps someone!

Thanks. Any pictures?

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Just after...not before. Here you go.http://986forum.com/forums/uploads02...1474660796.jpg
http://986forum.com/forums/uploads02...1474660817.jpg
http://986forum.com/forums/uploads02...1474660840.jpg

Wow that looks great
 

I used to do quite a bit of rock polishing and we used Cerium Oxide as a final polishing agent....had no idea about the glass applications. Actually when it came to Lapidary work Tin Oxide was considered a better grade of final polish....I wonder how it would work or if it would be better ??

That looks good.

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Gonna Look Like New, Too
 

An hour ago I met a county tractor mowing the roadside. He threw a large rock and busted my windshield. Oh well, looks like I'm getting a brand new windshield.

Thanks, I'm going to look at doing this. My Boxster and my daily driver have so many small dots from road grit they look like a galaxy when I drive into the sun. My daily commute is 60 miles each way with over 50 of that on highways which are like grit storms. But I know if I replace the windshields I'll have a rock crack the new windshield right away!

Used cerium Oxide on mine about 3 months ago...it really does a great job...one tip...it can be messy....the slurry can easily be slung onto the top, hood and surrounding areas. I'd suggest masking/covering those areas

Awesome! This has been on my list of things to do, as there are wiper blade scratches on my boxster windshield, and I wanted to restore like-new clarity.

As an experiment, I tried polishing a section of a car windshield a Menzerna automotive paint polishing compound that is supposed to work on "hard" clear coat (thinking that might have some chance of working on the super-hard glass windshield). It seemed to make some progress, but it was far too slow to want to do the whole windshield with it.

So you just bought this powder and mixed it into a slurry/paste with water, and only took 20 minutes to do the whole windshield? Sounds pretty easy!

Did you end up with any optical distortion through the polished surfaces afterwards? (This can be a worry when polishing an optical surface if material is not removed evenly enough.)

@jakeru depending how badly your windshield is marred, it may take quite a bit longer than 20 minutes.....I had some heavy wiper blade marks on mine....took me closer to 1 1/2 hours as I worked in small sections...about 2 ft square....buff...clean the section...evaluate...repeat as needed while viewing from all angles to ensure you got all the marks.

no distortion afterwards.

Agree with Dan....mine was far quicker but it could take you longer. No distortion just beautiful clarity.

Weather allowed me a good car detailing day today and after getting the exterior and interior clean, I tried using some cerium oxide polish on the front windshield to remove these annoying, fine wiper scratch marks. I got about 1/3+ of the windshield done before it got too dark, but it seemed to work well!

It definitely took some effort, but after taking for a spin tonight and I think it made a huge improvement! As I ran out of daylight, I'll do the drivers side and center tomorrow.

I used CarPro "ceriglass" brand cerium oxide cream and 5" rayon pad on my harbor freight dual action polisher.

At a speed setting of 2-3, I found it didn't sling any stuff around. I had the the rubber windshield gasket and trim taped off to protect those items. Probably about 3-4 times per zone I was polishing, I would add a bit more cerium oxide cream, and mist some water spray on the area being polished and the pad, to re-wet the drying polish, and keep going. I did press down pretty hard, (this rayon pad is pretty thin, and hard stuff - kind of like very stiff, dense felt) and it vibrated quite a bit. It was a good bit of effort! I found the 5-1/4" pad size had a perfectly matched radius to the curved upper corners of the Boxster windshield.

One thing interesting is I have Aquapel on the front windshield, applied probably 1-2 years ago, and especially compared to where I polished the glass with the cerium oxide, it was a night-and-day difference where the old Aquapel was - still beading up water, too! Although not quite as nicely as I remember after being fresh applied. (I've been really happy with the Aquapel treatment, plan to reapply a new Aquapel treatment after I've got the glass polishing completed.)

I have had this 6 speed tool for many years and so far no problems with it's operation. It's just like the 6 speed Porta Cable unit that cost well over $150. I got it on sale at HF for less. For me, it's a must have tool.

6 in. 5.7 Amp Heavy Duty Dual Action Variable Speed Polisher

Jthoms1,

Thanks for the links, review and the pics. Looking forward doing mine the same way you and the others did. Great improvement

Lew - I've also been quite pleased with my Harbor Freight dual-action polisher! I changed its backing plate to 5" for the rayon glass polishing discs I linked above. I've found a range of very economic supplies, like backing plates, polishing pads on eBay. (I've also have made some modifications to my unit, like putting on a 20'-long power cord, fixing/optimizing the clearances of transmission gears, and changing the grease.) I've tried harbor freight's newer model dual action polisher, which has a smaller diameter motor that runs at a higher motor RPM, and didn't like it as much as the older, quieter, more sturdily-constructed unit.

I took a photo this morning of the partly-polished windshield in the rain, which shows the hydrophilic quality of the clean, polished surface (on the left) versus the more hydrophobic surface with old Aquapel treatment (on the right).

I tried the cerium oxide powder on my daily driver back in the early fall. I used the glass polishing pads like jakeru, but with my Porter Cable random orbital polisher. It isn't dual action, only random orbital. I did not spend a lot of time on the windshield, but it didn't look like I made much progress on the thousands of tiny specks in the glass from road grit. I don't have issues with marks from my wipers, just the specks since I do all my driving on highways and the daily driver has 93,000 miles already. So, here's my multi-part question-If I spend more time on the windshield, can I expect to make any improvement on the tiny specks? And if so, do I need to use a polisher that isn't a random orbital motion? And if the random orbital polisher should do the job, should it be at a higher or lower speed?

I would think a firmer pad and higher speed with more downward pressure. Others might agree.
However it's your call.

See this link for background
Rotary Buffer vs DA Polisher vs Traditional Orbital Buffer

Thanks for that. I am going to try a 5 inch hook and loop backing pad on my 6 amp Harbor Freight angle grinder. I'm getting to the point in my life that I don't want to buy any more tools that I won't use very much. If it doesn't work, I've lived with the windshield and I'll continue to until a rock tells me it's time for a new windshield.

Not likely. I've investigated this for my own DD.
When there are actual chips out of the glass, polishing will never remove enough material to make a noticeable improvement.
Time for a new windshield.

Thanks, then I'm waiting. I know that if I get a new windshield, a rock will find it!

Hi Paul - if you didn't glean from the link Gelbster posted already, "random orbital" polisher is another name for "dual action" polisher. Basically, it oscillates in small circular motion, while allowing the pad to rotate freely. The small oscillations help keep the edge from digging in.

Yes, I also noticed those "specs" in my glass as I was polishing my windshield. As BoxsterSteve said, the very fine abrasives and polishing techniques described in this thread aren't aggressive enough to have any significant effect on those.

A rotary polisher is generally the most aggressive polishing tool. The drawback is the relatively fast-moving edge can easily "dig in", making even removal of material more of a challenge. However, I think the issue for pock mark removal is too fine of an abrasive.

Personally, when using a dual-action/random orbital, I like the speed set low enough that it doesn't sling material. By controlling downward pressure, you can influence cut rate. Running things at higher speeds, or too much downward pressure, can also input more heat into things, which can be problematic if things get too hot. In my case, I managed this heat by re-misting with water from a spray bottle a few times.

I have a set of diamond polishing pads for polishing stone/granite countertops, that are designed to use with rotary polishers, and ideally, flooded with a constant flow of water, as both a coolant and to keep freshly removed grit removed. While it would be an interesting experiment to try using them to polish automotive glass, and I'd be fairly confident they could break through at least some of those "pocks", I'd be very fearful that attempting this may result in uneven material removal (more likely the more aggressive you get with removal). You could easily make things worse (inducing optical distortions/aberration) than just leaving the small pits! Not to mention the time and effort required compared to the alternative of replacing the windshield.

You might look into some sort of windshield chip-filling resin might be workable to fill your pock marks, but I can't say whether it'd be worth the effort or not. Typically the chip-filling resin is done one chip at a time, and is UV-cured. The excess resin can be mostly shaved off flat with a razor blade afterward.

Thanks for your detailed response. These specks in my windshield of my daily driver, and also in my Boxster, are very small, and there are lots of them. When the windshield is clean, and I'm driving into the sun, it can sometimes be like looking through a galaxy of stars in the sky on a clear night. It's annoying but not the end of the world. If I'm not driving into the sun, if it's raining, or night time, you can't see these specks. You can barely feel them if you run a finger nail over them. I'm going to try again in the Spring, first on the daily driver. If I get some improvement, great, but if not, I'll leave it alone until the time comes that I need a new windshield. I appreciate the advice and things I learn here!

I know exactly the specs you are referring to... here are some views through the polished side of my ~116k mile Boxster windshield, where they are clearly visible. First photo is an overall view looking into bright, glaring sunlight, and second is a zoomed-in view looking into an overhead light in an underground parking garage:
http://986forum.com/forums/uploads02...1485240901.jpg
http://986forum.com/forums/uploads02...1485240930.jpg

That said, it looks better than before polishing. Below, notice those same two scenes viewed through the unpolished side of my Boxster's windshield...
http://986forum.com/forums/uploads02...1485241132.jpg
http://986forum.com/forums/uploads02...1485241151.jpg

These wiper blade scratch marks make really annoying, moving rows of glaring parallel-line reflections which constantly change orientation as the bright moving lights outside the car (especially worse at night) move around. The worst spot in the windshield for me is the area where both of the wipers overlap, as there are glaring lines there at not just one, but two unique angles!

On another site I read about using BAR KEEPERS FRIEND to polish glass, and for me it worked great. I mixed some into a paste and rubbed it on the glass (unfortunately by hand). Took some elbow grease but it did a great job..... I recommend it! Just be careful to keep it off the paint and rubber surfaces.

Been reading quite a bit here.

Is it fair to say that this requires a great deal of effort? Trying to find out if it would be just easier if not more effective to get the glass changed by the dealer here. Not cheaper unfortunately, they charge US$2k here hence why I am so interested into this thread.

Anyone managed to get most of the little rock-hits off? I'm looking for a better night vision and those rock marks is what ruins it all in my case. Any tips you have, please chime. Jakeru mentioned resin filling, if anyone knows about any/tech available do add

thx

FYI, guys, after driving around with the half-polished windshield, I've come to realize the polishing operation actually has added some distortion, which is a contrary result to what you said above.

I suspect it's done it for you other folks who have polished, but just not to a severe enough degree that it's been noticeable to you guys. If I polished my whole window so I didn't have two adjacent alternatives (unpolished vs polished) to compare, I may have not noticed it too. It's a bit subtle, to the point it would even be challenging to capture with a photo.

But if you want to look for the degree of distortion through the windshield, the best way to notice it is to find a perfectly straight feature on the other side of the glass (like straight edge of a highway median), look at it through manually polished vs unpolished surfaces. Through unpolished, oe Porsche glass, (very good quality in terms of being distortion-free, by the way, especially considering its varying curves) the straight feature appears, well, straight; but through the manually polished surface, well, I'm noticing that same feature gets a bit "wavy" on mine. Most noticeable when your face isn't right up close to the glass, in fact, it might be easiest to observe from the outside of the car, looking all the way through it glass canopy to the other side.

As the cause of this is basically uneven material removal across the optical surfaces, I do wonder if using an interface pad between the relatively thin/stiff rayon polishing pad and the backing plate, and perhaps using less pressure may have allowed a bit more even material removal.