Living with modern windshield glass

[KEW]

I noticed it when I bought a 2002 model Chevy Malibu (the hatchback based on the Saab chassis).
It was Click and Clack on Car Talk that made me realize it wasn't just me getting more vision sensitive with age, but that the glass had changed.
Apparently the quality of glass used for windshields has gone down (that may be a mis-statement as the change may be beneficial from a safety standpoint).
When I was learning to drive (72-73) the glass on our 1960 model American Motors Rambler Classic Station Wagon would be totally clear when you cleaned it, but apparently current glass is more prone to chipping. The Rambler was 13 years old. My current Chevy Sonic is only 7 years old, but if I am driving into the sun, my windshield might as well have glitter on it. I am pretty sure it is essentially being sand blasted by all of the sand and small rocks being thrown by trucks, etc. One thing I can say is I have not had to replace my windshield because of a crack from a rock, it seems like with the old glass it would be very unlikely to go 150,000 miles without having a big crack, so I wonder if the new glass is somehow easier to make a "divot" in, but less likely to spread into the kind of cracks I used to experience.
At one point I was going to a conference every year and there was a shop that would change out the windshield when I was there for only ~$200, so I replaced my windshield every 2 years. However, I am no longer going to that conference, and I suspect that shop got bought out and "gentrified" into a trendy sandwich shop.

So, what I am wondering is:
Does anyone know more on the change of the type of glass used for windshields?
Do nicer ($$$) cars have glass that is less easily chipped?
Does anyone know of a strategy or service to restore the glass - I had a chip patched once and it seems like that method might reasonably be applied to the entire window to fix it, but that may cost as much as a new windshield.
Thanks!

 

[snakeeyes]

I heard before that the quality of original windshields is often compromised for less weight. Probably helps with gaining better fuel economy in tests.

 

[lovinthehd]

Check into your insurance, mine has a free replacement program. I'd gotten a large rock chip in my windshield a few years ago, got the free replacement, within 2 days it had a new chip....shitty road surfaces....just waiting for this crack to grow a bit before I bother going in for another replacement....

 

[Irvrobinson]

I can tell you, Kurt, that I've noticed no difference in windshield glass durability over the years, or domestic versus European cars. Two things have changed, IMO. First, the rake of windshields has declined for aerodynamic purposes, and this might be a factor in glass damage. Second, there are a lot more vehicles on the road, namely big pickup trucks and SUVs that have tires with more aggressive tread that tend to grab and then throw off rocks more than simpler tires with shallow tread. In the desert southwest windshields are seldom perfect; rocks are everywhere. They chew up the paint too.

 

[highfigh]

Hard glass breaks, softer glass chips and since the glass is at a lower angle, it's not as if the stones are going through a window on a house. I don't think the new windshield on my van was more than a couple of weeks old before it was chipped. Hasn't grown, though. Lots of tiny specks, though. Never looks clean unless I spend a lot of time with it.

 

[nbk13nw]

My 05 Mustang was as stated above after a couple of years. Like a star field at night. I bought the required sanding disks and compound and polished the front glass to perfection. Again, a couple of years later another star field. Thousands of little micro chips. I gave up in polishing it again. Eventually I have had to replace the windshield twice over the last 15 years. Even the new replacement glass acts the same.

I had an 89 Mazda B2200 and after 250K miles the front glass looked new.

 

[Irvrobinson]

I had an 89 Mazda B2200 and after 250K miles the front glass looked new.

Uh huh.

So how does one go about making glass "softer"?

 

[nbk13nw]

Uh huh.

So how does one go about making glass "softer"?

Could not begin to tell you. All I know is what I have experienced in an 05 Mustang bought new.

 

[Out-Of-Phase]

Has anyone even asked respected automobile glass shops for their input on this issue?

OEM vs Aftermarket
Domestic vs Foreign

Get information from some pros in your area.

Is there an auto glass forum in the Internet somewhere rather than asking here?

 

[TankTop5]

There are differences between some OEM windshields and aftermarket but hardness isn’t one of them. Some vehicles have sound absorbing windshields that have a thicker laminate in between two thicker sheets of glass like Cadillac, Toyota and Lexus have a heating element in the windshield and many new vehicles have “hi-tech” windshields that have special sections for advanced safety features. After market windshields run about $200-$250 while advanced OEM windshields can run $1,200 or more, if you have one of these you better get insurance with windshield protection.

Back to the question of hardness, windshield glass is porous, if you look at it under a microscope it will have lots of holes. Debri that hits your windshield will sometimes hit one of these holes causing a pit or crack, if something doesn’t hit one of these holes the windshield is harder and wins. There are windshield treatments I though were snake oil but have worked well for me, basically epoxy that fills in the pores and gives you an incredibly hard windshield.


Sent from my iPhone using Tapatalk

 

[highfigh]

Uh huh.

So how does one go about making glass "softer"?

I googled 'soft glass vs hard glass' and found this-

" “Hard-glass” is an acronym for borosilicate glass, like Pyrex or Kimax. “Soft-glass” is an acronym for soda-lime glass, or a higher expansion type glass, (88-92 COE). Lab glass is generally made from “hard-glass”, (borosilicate). Bottles are generally made from “soft-glass,” or soda-lime glass."

https://www.aceglass.com/dpro/kb_article.php?ref=3469-WAHX-5341

 

[Irvrobinson]

I googled 'soft glass vs hard glass' and found this-

" “Hard-glass” is an acronym for borosilicate glass, like Pyrex or Kimax. “Soft-glass” is an acronym for soda-lime glass, or a higher expansion type glass, (88-92 COE). Lab glass is generally made from “hard-glass”, (borosilicate). Bottles are generally made from “soft-glass,” or soda-lime glass."

https://www.aceglass.com/dpro/kb_article.php?ref=3469-WAHX-5341

I was referring [poorly] to just windshield glass, but as long you brought it up, the hardness champ I understand is Corning's Gorilla Glass, like in my iPhone.

 

[highfigh]

I was referring [poorly] to just windshield glass, but as long you brought it up, the hardness champ I understand is Corning's Gorilla Glass, like in my iPhone.

I have seen the TV ads for that- pretty cool stuff.

 

[Swerd]

highfigh is right about borosilicate glass. It's preferred in the lab because it resists high temperatures, like boiling (100°C), sterilization (121°C with elevated pressure), or higher. It also is more resistant to most harsher chemicals, with the exception of the rarely used hydro-fluoric acid. And yes, it's stronger and harder. It's also used for cooking and baking in homes.

Soda-lime glass was rarely used in labs I've worked in. It can be easily attacked by many routine lab chemicals, it can't easily be sterilized without cracking, and it tends to absorb dilute proteins from solution.

It's been my experience that windshield glass used to be much harder. I'm not sure when, but about 20 years ago I started noticing how many cars had abrasion marks where windshield wipers swept. That never used to happen in the past. I always assumed the car makers substituted lower quality windshield glass to cut costs.

 

[Rickster71]

Modern automobile glass is simply thinner and lighter, due to the Government's forced fuel economy increases.
Increased fuel economy is great! However, when you have bureaucrats forcing engineers, cars get more plastic that breaks, thinner body panels that dent and cave in to weight, and thinner glass that breaks.

This isn't a judgement by me. It's simply how it is.

Corporate Average Fuel Economy (CAFE) Standards
Passenger cars are notoriously pressed with “stricter” emissions and efficiency rules as opposed to trucks and SUVs, and the CAFE standards are no exception – under the current laws, passenger cars are required to reach 54.5 miles per gallon by 2026.

 

[highfigh]

Modern automobile glass is simply thinner and lighter, due to the Government's forced fuel economy increases.
Increased fuel economy is great! However, when you have bureaucrats forcing engineers, cars get more plastic that breaks, thinner body panels that dent and cave in to weight, and thinner glass that breaks.

This isn't a judgement by me. It's simply how it is.

Corporate Average Fuel Economy (CAFE) Standards
Passenger cars are notoriously pressed with “stricter” emissions and efficiency rules as opposed to trucks and SUVs, and the CAFE standards are no exception – under the current laws, passenger cars are required to reach 54.5 miles per gallon by 2026.

Don't forget about CARB (California Air Resources Board)- they have a good amount of influence in this, too.

The body panels that buckle are intended to do that as a way to absorb energy in a crash, so it does provide a benefit to people inside and when peoples' faces hit a windshield, which is better- glass that breaks easily, or is impenetrable?

Don't kid yourself- the insurance industry is behind a lot of things that are seen as 'intrusive'. ABS brakes, throttle by wire, sensors for objects and other vehicles, on-board cameras.....they want noting more than vehicles that can be controlled by a computer in order to prevent crashes. I'll never believe it's because they care about people- it's always about money, for the insurers. They care about that more than anything else.

Considering the lack of progress in fuel economy in the last 15 years, I seriously doubt we'll see 54.5 MPG anytime soon. Also, the EPA changes the fuel formulation whenever they feel like it and the auto manufacturers don't always get a lot of time to react.

 

[KEW]

Good to hear that I'm not the only one who has experienced that glass has changed, and the Car Talk guys really are an expert reference (although my memory is involved, so there is that).
For those not familiar, the Car Talk guys are brothers. One of them runs a repair shop and the other is a professor (of Materials, IIRC) at MIT. The Prof. apparently drops by the auto shop to visit his brother fairly often, they are Italian and seem to be very close and are just a lot of fun because of their rapport with each other and the way they call BS and rag on each other! But at the end of the day, they are very knowledgeable!
It is a radio show on NPR where callers call in to ask questions about cars and car repair. No longer making the show, but re-runs are still on.

 

[slipperybidness]

highfigh is right about borosilicate glass. It's preferred in the lab because it resists high temperatures, like boiling (100°C), sterilization (121°C with elevated pressure), or higher. It also is more resistant to most harsher chemicals, with the exception of the rarely used hydro-fluoric acid. And yes, it's stronger and harder. It's also used for cooking and baking in homes.

Soda-lime glass was rarely used in labs I've worked in. It can be easily attacked by many routine lab chemicals, it can't easily be sterilized without cracking, and it tends to absorb dilute proteins from solution.

It's been my experience that windshield glass used to be much harder. I'm not sure when, but about 20 years ago I started noticing how many cars had abrasion marks where windshield wipers swept. That never used to happen in the past. I always assumed the car makers substituted lower quality windshield glass to cut costs.

You are pretty much on point with the glass types. But....HF is not rarely used. It just depends on your industry. It is extremely prevalent in the semiconductor industry, precisely for it's ability to etch SiO2.

 

[Rickster71]

Good to hear that I'm not the only one who has experienced that glass has changed, and the Car Talk guys really are an expert reference (although my memory is involved, so there is that).
For those not familiar, the Car Talk guys are brothers. One of them runs a repair shop and the other is a professor (of Materials, IIRC) at MIT. The Prof. apparently drops by the auto shop to visit his brother fairly often, they are Italian and seem to be very close and are just a lot of fun because of their rapport with each other and the way they call BS and rag on each other! But at the end of the day, they are very knowledgeable!
It is a radio show on NPR where callers call in to ask questions about cars and car repair. No longer making the show, but re-runs are still on.

Car Talk was a great show, lots of laughs. The older brother Tom (the prof),passed away in 2014.
Just remembered another disadvantage to the thinner glass. The rain noise is now much louder, it sounds more like hail hitting the glass.

 

[Swerd]

You are pretty much on point with the glass types. But....HF is not rarely used. It just depends on your industry. It is extremely prevalent in the semiconductor industry, precisely for it's ability to etch SiO2.

OK, HF was rarely used in the biochem labs where I worked. I only remember it getting used once. And the boss made everyone else not using it take a long coffee break, clearing the room while it was being used.

HF is a very strong acid that can eat through the glass jugs that strong concentrated acids come in. They have to use plastic coated glass jugs where the plastic is thick enough to never ever crack. I wonder what safety precautions the semiconductor industry has to use for HF.