Car rear window scratch,

[gordon stephenson]

As per title, has anybody got any experience in buffing out minor ? scratches, I see there are kits available with various "grinding"compounds, Are they any good, Not in a terrific rush, Could do a little at a time as long as my legs hold out, hoping for some good advice from the forums font of all knowledge< Gordon,

 

[RWD3M]

Oh, by the way, heard you've nbeen a little under the weather of late, good to see you on the mend!

 

[Craig-SM]

As per title, has anybody got any experience in buffing out minor ? scratches, I see there are kits available with various "grinding"compounds, Are they any good, Not in a terrific rush, Could do a little at a time as long as my legs hold out, hoping for some good advice from the forums font of all knowledge< Gordon,

I’ve used normal car polishers before on a machine polisher

 

[Kram]

Have a photo?
There are certainally polishes that will do it but I have not tried but I have been considering it, probably wants a fine diamond polish.

My car is old with a scratched front window, wiper and swirl marks that are irritating in bright sun light, but otherwise perfect with no chips..

 

[Domdom]

The polishes are cerium oxide based in various grades. The common things I’ve found are that they take forever and if you try to rush they generate a lot of heat. On a back screen, heat will shatter it. It’s toughened, not laminated. I am relatively patient but even I gave it up as a bad job.

 

[tigdlo]

I had a kit years ago with I think zirconia abrasive, it was very fine, almost like icing sugar, it made old car windows look bright and improved their appearance but didn't remove enough glass to hide scratches with any real depth, I suspect it only really softened the edges of even the most minor scratches to make them less obvious. I would think you would need a kit with various grits to work through to remove enough glass.

 

[gordon stephenson]

Some of the university of youtube, say people start with too fine an abrasive and nothing really happens, got to start with a more aggressive one to start with to remove glass down to the level of the scratch,

 

[MetalMonkey]

Echo the above.

Cerium Oxide is the polishing compound, sometimes they come with some fine abrasives. Practice on some scrap before even attempting it.
You can "refine" light scratches and some water staining. But it does take for ever. Deep scratches, forget it.

 

[Nomad]

Local windscreen etch places used to have the kit to polish windows - worth a phone call ?

I've got some decent polishing kit but have no idea what grades / polishes are needed for glass (but I'm interested as I have some wiper scratches on my windscreen)
(
What car? Which glass? (just noticed the title says rear screen. Oops!) What's your insurance excess? If it's a distraction (dangerous?) your insurance might replace it without affecting your no-claims as long as you pay the excess...

 

[Smallfry]

We used to get scratches out of glass table tops with fine garnet paste. Takes a while though.

 

[colnerov]

I was always told Jewellers rouge will do it but was slow, but knew I wouldn't have the patience for it. Having read the other posts, I would be interested to know the actual abrasive it is, even though I still haven't got the patience.

 

[Misterg]

It's no different to prepping for paint: You've got to grind away enough material to get rid of the scratch and back to a smooth surface, then work through finer and finer grades of abrasive to improve that surface until it's smooth enough that polish can do the rest.

For stock removal, silicon carbide grit: 180->400->600->800->1200->finer if you have it.

After each grit size, everything needs to be scrupulously cleaned, as even a single particle of coarse abrasive will ruin the process. If there is even a hint of pitting visible on the surface, then continue with the coarser grit until it has been removed.

When the surface is so smooth that is has an almost waxy sheen to it, with absolutely no signs of pitting, it's ready for polishing.

The best polish for glass is cerium oxide powder suspended in water as it polishes chemically as well as mechanically. Other fine abrasives will also work, but more slowly, and may not give as 'clear' a surface.

Soft polyurethane works well as a lap to hold the polishing mix.

It takes a long time, but the right laps, etc. help.

Anything more than the lightest spot repair is likely to show up as optical distortion at certain viewing angles (but probably not noticeable when viewing straight on).

That's the process, but I'm not sure I would be brave enough to tackle a car window that I cared a lot about!

 

[Kram]

Another option which may be far quicker is to fill the scratches with 2k clearcoat. Im not sure if clearcoat will stick to glass and would likely want keying at 800 grit or so.

Hammer and replacement is likely best, tho sometimes they can leak. It seems replacements never seal as well as originals.

 

[gaz1]

put it this way is the scratch worth your time and doing never mind paying the money out for it

as your unsteady on your feet is it worth doing or worth leaving alone

with front screen scratch or cracks its call the glass company and have the window repaired or replaced

the question you need to ask does it really need messing with ?

 

[gordon stephenson]

Thank you for all the "tips and tricks" I always would practice before diving into the real job, Looks like more thought required,

 

[Ali]

Hi Gordon,

I don’t have any experience with Cerium Oxide, but found myself researching what it is / uses recently, and I think the comments above are correct, ie., if you can actually see the scratch it’s probably too deep and you need to cut back further before the stuff will be any use. I think it’s used for telescope / maybe camera lenses.

Anyway, I was only looking it up because I found a kit in my late father’s workshop and got curious. If you think it might be useful and would like to have the kit it’s yours - just PM me your address.