My windowscreen appears to have scratches in it?

[smurf]

I had read the thread on removing the water spots of glass. Cool so of i went to buy some No4 as my wagon had bad water spotting on all the windows .

I used the Cyclo for this job, just a couple of drops on each pad and away we went

Great job was done all spots where gone

BUT wait! late afternoon went up town the sun was in my eyes and all i could see was very fine scratches all over as in swirls. I had never noticed the swirls before I do not know if they were already there and just hiding under all the gunk or did the the no4 put them there.

ANY IDEAS !!!!!!

[Mike Phillips]

In all the years I've been working on cars I've never seen M04 scratch glass.

If your windows were covered in water spots for some time now then it could be the scratches/swirls you're seeing now have always been there and now that you've removed the gunk and mineral deposit build-up you can actually see the condition of the glass.

[gbackus]

Some of the newer windshields have plastic resins mixed in so that it "fractures" rather than shatters upon impact. Each year, these windshields are becoming more and more plastic resin, and less glass.

Although not recomend by meguiar's, I've had good luck polishing several windshields using the 83/82 combo, and haven't noticed any scratches as a result.

[Mike Phillips]

George, can you post a link to any service bulleting that states the outside surface of automotive glass is anything but glass?

I've read one or two mentions of this before but I've never seen any hard data.

As for the windshield, because wiper blades are meant to rub against the surface to remove water in inclement weather, I'm not sure their is a plastic resin coating that can hold up against this kind of wear and tear over time like glass.

If there is a resin that is made to hold up against windshield wipers rubbing against them and it won't dull or scratch over time, then this is some kind of plastic resin!

[Mike Phillips]

Re: My windowscreen appears to have scratches in it?

Originally posted by smurf


Great job was done all spots where gone

What kind of car are you working on and what year was it manufactured?

I'm going to guess the defects you're seeing were already in the glass, M04 uses diminishing abrasives and I've never seen this product instill a swirl or scratch in glass whether applied by hand or machine.

[gbackus]

Originally posted by Mike Phillips
George, can you post a link to any service bulleting that states the outside surface of automotive glass is anything but glass?

As for the windshield, because wiper blades are meant to rub against the surface to remove water in inclement weather, I'm not sure their is a plastic resin coating that can hold up against this kind of wear and tear over time like glass.

Sorry Mike, this is second hand information, but the way I understand it is that it is not a coating on the glass, but an additive in the makeup of the glass.

I was pursuing a warranty claim with ford because my windshield kept exhibiting excessive wiper marks. The OEM supplier of auto glass to ford is CarLite, and after the second windshield exhibited excessive wear marks, after three months, the dealership worked out a deal to get me a PPG replacement. This windshield also sarted showing wiper marks after a few months, and because the dealer wanted to close my claim, they put me in contact with their PPG rep.

The way he explained to me was that traditional glass is mainly silica(sand), lime and ash. But modern glass has many additional additives, such as boron oxide which makes glass heat resistant and makes up to 25% of the headlight covers for xenon headlights. In particular, there are plastic like resins that make a windshield more prone to fracturing vs. shattering, but these resins also make the glass softer and prone to scrtaching.

As a result I ended up with a closed warranty claim, and a badly scratched windshield. I can't say how accurate this information as it is second, or possible third hand, but I have been given similar information(soft glass due to additives) by other people. I have also noticed that many newer cars seem to exhibit far more wiper marks than older cars.

That's the best explanation I can give, sorry it isn't more concrete.

[Mike Phillips]

To date, that's the most information I've ever read on the chemial make-up of new glass...

Where's a glass chemist when you need one?

[smurf]

Hi mike

my wagon is a 1991 Toyota Surf 4x4
I have had it for 2yrs now 1st owner since it came out of Japan
so maybe the markes where always there but I could never see them untill now

[smurf]

also with the no4 am i better off to use a firm pad