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Discussion Starter #1
Has anyone had extensive polishing done on - actually any - windshield?

I thought I'd found a new (glue in type) windshield for my '75 Alfeta GT, but it turned out to be for the later Alfetta GT's and GTV6's.

Before I get the speech, the paint, looks terrific under the stainless - no bubbling, etc.

I've rummaged around the Internet/YouTube and found a video of using polishing pads of varying types/grit, but the video only played music so no real information as to what was actually used and where to get it. They appeared to be around 6" in size. Another video showed a huge polishing machine going very slowly (and apparently automatically) across the windshield, then returning. It was an elaborate set-up, but did prove to me that it is possible to do more than give them a good (mild) polish. Ads in google say the Repair of Windshields. Their idea of repair is to replace the glass.

I have about ten fairly big chips - size of a big dot - but no major scratches or really large pits - but it does have a jillion (+ / -) small 'sand' pits which is blinding when driving facing into the sun.

Biba
 

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But Mad North-Northwest
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Rule of thumb is that anything you can feel with your fingernail can't be polished out. Maybe the technology has improved, I don't know, but I doubt you're not going to be able to do anything about those sand pits.

I've used a cerium oxide glass polishing kit myself: this is cerium oxide powder that you mix with water to form a slurry and then polish with a pad and buffer. It works okay on super-fine stuff, but again it won't fix all those little chips.
 

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Windshield polish ?

On my Milano 12 yr old windshleld, realllly pitted, like sand blasted. Can't see in early morning with moisture, till it dries out.
Used headlight polishing compound on a foam pad and electric drill. This did not create any uneven surface condition.
Changed the surface from "unacceptable" to "not that crappy". Seemed to last for a year or so as it gradualy returned to "unacceptable".
 

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Discussion Starter #5
I have heard of people having a fairly serious windshield wiper scratch and it was polished out with little or no distoration. I might give the Alfetta's windshield a try with my Eastwood kit. I just realized I can attach it to my cool Makita polishing machine so I can hold it at 1500 rpm as is required.

Still, if anyone else has had a positive experience with a service who polishes out windshields I'd sure like to know.

Not the same thing but there is a (home window type) glass shop in these units and they use a fairly coarse sanding discs to polish the edges of thick glass.

Biba
 

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Push hard and live
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I bought the Eastwood glass polishing kit, and will report that it will work on haze and very slight scratches, but requires mucho man hours to achieve results. I decided after spending several hours on the door glass for my 102 to just have new glass made. This cost $180 for two mounted into the original bottom frame, so I bought a couple of extra pieces of glass.

I watched a video of a professional glass polisher, and can see that having serious industrial equipment, years of experience, and patience might restore a hazed and road-rashed windshield or door glass. A new windshield for my 102 was bought for about $500 including freight, and I have a hunch the polishing by an industrial expert would cost about the same.

It is a very slow process that requires starting with very rough abrasive and working up to finer and finer grades. There are no shortcuts.
 

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Discussion Starter #7
Don, I agree that if I do find someone who can make just an improvement on my windshield it won't be inexpensive. But what do you do if they are NLA? I have spare door and rear window glass, but no spare glue in windshield.

My thought is, that just like wet sanding fresh paint, you must start with pretty coarse discs (as you said) to be able to get down to a level that it will then (eventually) polish out. I'm sure this is where the skill/knowledge comes in so that it doesn't end up with a distorted windshield. In my googling I found a place that sells (real) diamond 'sand paper' for sanding hard finishes, glass being one of them. "Honey, I ground up the diamond from your engagement ring so that I can polish out..."

Biba
(Who doesn't have diamonds on the sole of his shoes.)
 

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But Mad North-Northwest
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Two problems with your plan, really. First off, glass is REALLY hard. It takes a lot of effort and time to polish it. Cerium based polishes help because they chemically react with the glass to ease removal, but even with that it's tough.

Secondly, distortion is a big problem. Look at the depth of those chips: couple tenths of a mm probably. To remove the chip, you're going to need to remove that depth of glass. That's a lot of glass. And unless you do it evenly over the whole surface you're going to wind up with a funhouse mirror effect.

I just can't see it working very well for you.
 

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Discussion Starter #9
Tom, while I'd like the small chips to go away, they aren't interfering with being able to drive towards the sun - meaning I'd be happy to get the glass far enough down to get rid of the miniscule 'sand' pits. And I fully accept that it would take a very skilled glass guy to grind the glass down that far, then polish it out with little or no distoration. If doing it myself, I'd spend a lot more time on the driver's side and center than the passenger's.

This is pretty long (9 + minutes) but demonstrates what is possible:

I'll add that I have the same Makita polishing machine that this fellow is using.

Biba
 

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I've spent some time grinding mirrors for telescopes, and working with companies that do this - not little hobby mirrors, but BIG ones. Common polishing tools are GLASS discs of 6 inches, a lot of really hard grinding compounds, and weeks to months in automated machines.

For a windshield, beyond 0.1 mm removed from the surface and it starts spalling (that is, micro bits of glass just explode off the surface). Its been heat treated to stress it, so it shatters "safely".

There just isn't enough glass to ever polish out a typical 20-year sand pitted one.

In farm country where dirt and road junk fly everywhere, new car windshields are often replaced every year or two because of the pitting. It's like being in a slow sandblaster.

There is no recovery.

Robert

PS - Did you notice that it takes WEEKS to MONTHS to polish........
 

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Considering the above mentioned reality of glass polishing my slight improvement probably came from really cleaning the windshield with my polishing compound. I did use lots of water and "windex" to lubricate the polishing device.
Whatever, it does seem to make an improvement.
 

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Local car club had a bbq and demo at Griot's new facility in Tacoma. They used their random orbital polisher with their glass polish on a 56 Ford wagon's windshield. It did an excellent job of polishing the glass...unfortunately the old glue inside the glass has yellowed over the years. I will try to rub out a wiper spot on my GTV one of these days.
Joe
 
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