Having performed restoration on both architectural window glass and auto glass/windshields it seems to me that windshield glass is becoming easier to scratch. This is why plastic razors are now available to detailers. I remember one scratch job that I looked at. It was a windshield. I found out very quick I couldn't use a high speed machine with the cerium. It would create a very bad burn. The scratches would only come out, without any burn, at very low rpms, and a very light "hand". Does anyone on this forum know anything about this?

Henry Grover Jr.
Glass Tech Services
GTSForums@hotmail.com
Specialty Services Are The Way!

technically no. but i have an opinion. Poor quality raw materials used in making todays glass. just about every one you get from any warehouse these days comes as a scratch and dent.

Butch,

That was a very insightful answer. If the mix is off the chemistry and physical properties of the surface would also be off. I will do some looking into the different companies that make windshield glass, and check on who checks on the precision of the batch. In the meantime I was curious to know if the bulk of your work is replacement. Also the scratches and dents that you mentioned, are they more like scuff marks or line scratches? Thanx for your input.

Henry Grover Jr.
Glass Tech Services
GTSForums@hotmail.com
Specialty Services Are The Way!

I agree, it looks like todays windshilds just dont hold up to a beating at all in comparison to the ones of yesteryear.I put a new glass in the company astro and in like 20k miles it was as beat up as some I see with 100k .Yes I think they scratch easier and are "softer" . Perhaps they have a mix now that is more likely to break insuring more glass will be sold by its nature ? I dunno .

I think if you research it fully, it's not poor quality in the raw materials, it's more likely poor quality in the handling of the glass by the distribution networks.

In the "old" days, most distributors received their windshields in full 30 lite pallets from the manufacturers. The only handling of the glass was from the pallet to the delivery truck.

Currently, many distributors get shipments from their vendors in mixed pallets, then they they put the windshields in their racks, handling them again when they take the glass out of the racks for delivery to their customer.

All of this extra handling makes the oportunity for more scratches and rubs.

I don't think the basic compostion of auto glass has changed in the last 40 years ( except for the introduction of solar glass which changes some of the chemical makeup of the glass)

In the immortal words of Pogo " we have met the enemy and it is us"

The glass of today is much thinner than the early curved glass and much more resistant to breaking during removal. I think most of the problem is with all of the debris on the roads. We have an 03 Tacoma that has 60 thousand + miles on it. The windshield is ready to be replaced it looks like it's been in a sand storm but hasn't been in one. It's freeway driving only(So Cal).

I was told the hadrness comes from the float line. A function of quality control and tracking thousands of bit of info as speed, tempture, distoration ect. The best gets used for windshields the rest gets used for other uses or sold to co. like Safelite that don't make glass. I think the sand is still the same.

I think it is in the batch myself.I can remember that before the early 90's there was a distinct difference between the manufactures.L.O.F. was a harder glass that was hard to break and scratch,It was also more brittle.When it did break it took off like it was in a 100 meter sprint.The same held true for carlite,mopar.PPG's was a softer glass.Scratched easier and got sandblasted very easy.When they received stone chips they didn't travel as fast thru the w/s.But then again that is the difference between saftey plate and safety float glass.Which is now where clarity comes into play.

Here's my 2 cents worth again.

When glass is made, as it cools, the outer surface cools faster than the center and is slightly harder
than the inner part of the glass.

When plate glass is made, the outer surfaces are ground and polished, and
the finished glass has a softer surface than float glass.

As has already been mentioned, safety plate glass windshield break more
easily than safety float glass windshields. The bad news is that no-one makes
safety plate glass windshields any more !

Happy New Year all......