Miata Mailing List: December 1998, Message #5203

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Dan Scolnick wrote:
} Subject: Re: New 99 {1MC}
} the problem with using polish to take out scratches in the window is it
} makes lotsa little scratches to replace the few big scratches.  You don't
} notice the little scratches in front of your eyes except under really
} stressful situations, like fog, frost or driving into the glaring sun, when
} the little scratches make a wonderful spiderweb that obstructs your view.

I missed the original thread, but I assume we're talking about
repairing scratches in the windshield. I just went through this with
my Miata.

On a rainy day a few weeks ago, I turned on my wipers and happened to
have some pebble-like object stuck in the driver side windshield wiper
blade. At first I thought I had a thin arc of muddy dirt forming
across the windshield but it turned to be a scratch about 2 to 4 mm
wide and a length of over 1.5 ft, and direclty in front of my field
of view.

I did some web and Usenet searching for scratch repair techniques, and
found some methods. There are glass polishing kits available from
Eastwood Co.  (www.eastwoodco.com) or from the JC Whitney catalog that
come with a circular buffing pad for your drill, and a jar of glass
polishing paste. The general consensus was that if you run your
finger/fingernail across the scratch and you can feel it, the scratch
is too deep to be buffed out. Fortunately my scratch was not that
deep.

I tried ordering the polishing kit from Eastwood, but they were out of
stock. Being impatient, I tried another technique mentioned in the
sci.optics, sci.astronomy and rec.autos.* newscroups. Some folks there
referred to a powder called cerium oxide that's used in the final
phases of polishing lenses for build-it-yourself telescopes. I figured
if it's good enough for astronomers, it must be good enough for a
car driver.

I purchased a 4oz. package of this stuff for $9 from a nearby optics
company (Newport Glass in Costa Mesa [www.newportglass.com]). It's a
pink powder that came with no instructions. I mixed about a teaspoon
of the cerium oxide powder with water to create a paste, then for the
next friggin hour and a half, I buffed the scratch out by hand using a
cotton towel and a lot of brute force. I took some precautions and
wore a surgical mask and latex gloves when I used the stuff. Something
that polishes down glass is probably something that you don't want
to breathe or embed into your skin.

The results are very good. The scratch is almost not visible, but if
you look, you can still see some parts of the arc. But instead of
being very opaque, what remain of the scratch is very transparent. And
there are no residual scratches as a result of my buffing actions.

If I had to do it again, I'd probably use the buffing kits from
Eastwood or JC Whitney next time. With the buffing pad attached to an
electric drill, it's a lot less tiresome. And I have a feeling that
their glass polishing paste must use cerium oxide or something
similar as the base compound.

 jaime villacorte  jaimev@netcom.com  http://www.wenet.net/~jaimev/miata.html
 Laguna Blue 94B    Irvine, CA