docstinger523

1989 s4
Windshield has micro-scratches and swirls.
Have tried clay bar with quick detail, and every glass cleaning solution around.
Must I replace windshield or is there a simpler solution?

Dave928S

The only material that will give any success is a powder called ... CERIUM OXIDE. It's a light brown powder that is used by glass manufacturers to polish glass edges, bevels, etc.

I've successfully used it to remove scratches in glass on construction projects, where glass replacement was going to be mega bucks.

It will be vitally important when using it to polish a windscreen, to keep the buffing pad on the machine moving to avoid any optical distortion effects; which you would get if you concentrate on just one spot for too long. You mix the powder with water to form a slurry/paste and apply it to a damp buffing pad on a machine polisher. It's expensive so you need to use a smaller pad, and don't have the machine going too fast or it'll fling it off.

You will need to spend quite a bit of time (probably at least an hour) going methodically over the whole screen. Places that cut and polish glass should be able to either sell you some or tell you where to get it.

Polishing should only be attempted if the marks are very shallow ... if there are any deep scratches you'll need to bite the bullet and put in a new screen.

Glenn M

Some links

http://www.eastwood.com/pro-glass-po...FYeD5Qod6VT0XQ

http://www.autogeek.net/lc-diy-glass-kit.html

quick search will find other kits

DANdeMAN

If you do try one system, please report here. I'm very much interested in the result.
Mine is in need of something like that....

Daniel5691

Seems like most of my glass issues are right in the 'pathway' of the wipers.
It would be so awesome if there were some sort of safe "reconditioning" windshield wiper that could be temporarily installed to tidy up the scratches and then removed...

I have found that cleaning with a clay bar, then really taking some time with uber-thin coats of RAIN-X, especially if you can get some moderate heat on the glass between coats, is a passable, but sadly temporary fix....

Any other "home remedies" for the screen-scratch blues?

Wisconsin Joe

Post #2 from Dave.

Cerium Oxide. You need to go to a glass place, not AZ or O'Riellys or similar (they won't have any clue what you are asking for). The "real" glass place I went to knew exactly what I wanted and had a little jar of it for $5 or so. I only used a little bit of it.

It did a really nice job of taking out much of the "wiper arc" scratches and the little pits. Not perfect, but a noticeable improvement.

OKB

I usually buff the windshield with rubbing compound, its really tough to remove any marks but repeated buffing will do some good after awhile,
there are windshield /glass repair shops that do the same with windshield buffers, and they claim to get marks off, to some extent

Hilton

Yup Cerium Oxide.. I removed a lot of the pitting from the windscreen of my '87 with it.

Buy some from your favourite lapidary supplies place (or some random interwebs shop/amazon). Put in a squirt bottle with enough water to make a slurry and squirt liberally on the windscreen.

Use a random orbitail with a small (3 or 4") wool pad, and start working.

I did the whole windscreen several times.. first vertical stripes, then horizontal, then diagonal, then opposite diagonal, and repeat as many time as necessary, so that coverage and time spent was even across the glass and I got no wavy distortion effects.

I need to tackle the passenger side window on my '89 too as its got vertical scratches from something in its past.

beetleything

Good thread ..thanks for the info.

Range Rover

Polishing the glass can be very effective. You'll need a buffer, glass polish, and a glass polishing pad.

Little video tutorial on glass polishing:

Captain_Slow

My windshield needs this polishing treatment, but the most obvious class scratches on my 88 and a previous 86.5 (and I've seen it on other 928s) are the vertical scratches on the door windows. Seem to be on the inside only. I'm guessing it is something in the doors scraping the windows as they go up and down. My windows are tinted, so it may also be that the mylar is much more easily scratched than the glass.

WallyP

"I'm guessing it is something in the doors scraping the windows as they go up and down"

The usual suspects are the felt pads near the top of the door - they get hard and contaminated. And, yes, the window tint scratches easily.

Captain_Slow

Thanks Wally!

Bertrand Daoust

Hello Jon,

I think Wally's talking about part #20 here:



Part # is: 928 537 085 03

Two per side.

There was a thread not too long ago about only changing the felt part.
This is interesting as the part itself is over 50$ each I think.

Edit: Found this thread:
https://rennlist.com/forums/928-foru...w-streaks.html

Ed Scherer

See also the old thread polishing scratches out of glass?? on this topic. Looks like the current offerings from Eastwood for scratch removal from glass are #12525 Eastwood Pro Glass Polishing Kit and #12526 Pro Glass Polishing Kit for Deep Scratches.

My one experience with scratch removal on my 928 was about 14 years ago using a similar product from Eastwood (which has been replaced by the above products) and was quite successful.