Bravo,

Be forwarned though. If you use this approach, to keep the cerium solution and the wheel cool. If you allow the wheel to become unlubricated, or too warm, the laminated glass that makes up your windshield is very susceptable to heat fracturing.
(Your sidelites and rear are tempered, so they can withstand substantially more heat.)

Mike

 

Polymer substrates are themal elastic and when combined with the glass content, create some stress factors that are very damaging.

Just like our tech article on buffing modern clearcoats indicates, the result of SAE studies, if you get the clear to hot, you stress it and weaken it.

Ketch

 

Mike--are you in the auto glass business? You sure do know your glass lingo!

The windshield usually is made up of two sheets of thinner glass, and a sheet of vinyl in between, and it's bent by heat, not tempered like the sidelites or backlite. So it is more susceptible to heat, pressure, etc. The windshield will crack but not shatter into tiny pieces like your other windows. The vinyl in between keeps you from going through the windshield. Just be careful what every you do, aftermarket glass is very expensive, the dealers make a killing on replacement glass.

 

Moral to the story? Wipe water off your glass at the first possible opportunity!
Rain-X works wonders, too Man, this is becoming a serious discussion.,,,,,98

 

Try Bar Keepers Helper (I believe contains Pumice) on the water spots. The use of Cerium Oxide will remove light scratches and most likely light etching, as that is what OEM glass makers use to fix questionable glass. You may make areas of visible distortion in the glass if you apply to much pressure. Scratch polishing is somewhat of a skill for glass makers.(not done much anymore - not cost effective) We use many types of items to remove calcium from glass. Citric Acid works well, but I don't know where to get it in a pure form like we use it. Vinegar, Lime-A-Way may work but I think may potentially harm paint and finishes. Bar Keepers helper is not risk free but if you rinse it off well should not harm the finish. I use it on the windshield everytime I wash my truck or wifes car to remove the road grime. It has actually improved a wiper scratch caused by a stone. Steel Wool is often reasonably effective on non-privacy glass but does leave scratches. If you use it on the privacy glass you may see metalic fine scratches remaining. Basically be careful using anything on your windows you would not use on your paint. Point of note: Auto windows are still glass. Made primarily from melted silica sand. Everything else in glass is either colorants, refining agents or melting agents. Auto manufactures have reduced the weight of glass by using thinner glass or less of it not by changing what it is made of. I hope this helps.

 

The engineers I work with at Ford, DCX and GM all told me sometime a go that polymers were added to the glass in order to lighten it without giving up the strenght required.

They told us that this if one of the reasons for the increased etching by enviormental fallout/acid rain.

Additionally, they have specified to never use steel wool on automotive glass, due to the added softeness and the marring of the surface, the potential to remove the very, very thin special coating applied.

Thanks, I am curious as to why there is a difference of opinion on this subject.

Ketch

 

Ketch,
I think you may have slightly mis-understood the engineers you work with or they don't know for sure either. Of course they don't make glass. (Except Ford Visteon, but Rumor has had it for a few years that they are working on getting out of the glass business) They buy it from people like like us. We currently make the F-150 Back light and Mustang Windshield as well as the Tarus/Sable OE and Replacement windshield. We supply Many OE customers as well. Anyway my point is that windshields are made typically of 2 plys of 2.2mm glass laminated together with a vinly polymer. This has been done for many years. (Bent Annealed Glass) Side lites and Backlights vary in thickness between 3.2mm upto occasionally 6mm. That glass is tempered. One interesting fact is that is that the surface of tempered glass is softer and more likely to scratch than annealed glass. The glass is extremely strong with upto 10,000psi of energy stored in the stress layers. Now as for reduction in weight what the desiners do is put 4mm glass in the front doors and 3.5mm in the rear doors instead of 4mm all around. the rear doors do not get the use so therfore does not need the strength. Weight savings. Manufacturers also use encapsulation (polymer) to encase the glass and mount it in body openings. Smaller piece of glass bigger piece of plastic. The glass does not contain any plastic though. One last item before you go to sleep and so I can get some food on what remains of my lunch time, the '97 and '98 F-150's had Ford Produced Coated glass in them for Privacy glass. This glass is coated on the inside and CAN BE SCRATCHED OFF. Just a word of warning if anyone tries to use a razor blade on the inside of the glass to remove anything.

OK you can wake up now.

 

Good info, will have to redo some training text.

Drop me a personal mail and will get you a set of goodies for all your help

Ketch

 

While, I am not in the Auto Glass business, I am in the commercial and industrial glass business. We deal with Mirrors, Laminated Glass, and Tempered float day in and day out. I might also add that auto manufacturers are able to get away with thinner glass that years ago, since the intruduction of tempered glass as side lites. Tempered glass is 5-7 times stronger than annealed. Therefore 4mm tempered has the eqivalent strength of 20mm glass (approx. 3/4"). The one downside of tempered glass, as you can see with the naked eye, is fine "dimples" and "waves" in the surface. This is the result of the tempering process (heating to almost the melting point and rapid air saturation cooling). If you look on your rear or sidelites (I noticed that my rear-slider is only 3mm I believe), you can closely see the visable pits and waves. Whereas the windshield, which is laminated annealed, is an almost perfectly smooth surface.

One last note (in case you're still concious), the windshields are not only laminated so we don't fly through them. If they were to be tempered glass, those little rock chips could concieveably be a shattered windshield at 60 MPH. Would not be fun.

Anyways, that's all for now on "Glass talk." Won't you return next week, when our subject is "Beveling, is it really worth the money?"

Mike

 

BrownHarleyford,
Many of the items you state are exactly right. I have a few additons to your statements. The waves in auto glas comes from either the glass being to hot in the horizontal roler hearth tempering furace or the forming tooling having a kink in the forming ring. the cause is typically to hot and mechanical. The pitting on the surface of the glas is caused by furnace operators trying to heat the glass to fast or making it to hot to avoid tempering breakage. In either case the weight of the thicker glass "crushes" it into the polluted ceramic rolls of hte furnace and leaves pitting. In reallity all tempered glass, bent or flat, will have some degree of pitting if tempered on a horizontal roller hearth furnace. (Most Common Type) Windshields bent on roller hearth furnaces do not require the heat to only bend them so the outer surface is not so soft and don't pit as much. Gravity windshield funaces have tooling carts that carry the glass only around the edge and so therefore nothing touches the viewing area of the windshield while hot. Gravity windshileds typically have better optics but worse shape than roller hearth furnaces.

Since you are a glazer, if you ever run into 12mm tempered glass the pitting at the begining of a run of that is usually horrible. It gets better as the heat in a furnace evens out and the heavy glass in the beginning pulls all of the debris off of the rolls. Just something to watch for.

n the near future you will probably start seeing the self cleaning glass put into buildings. I know that we have a contract with a few home window manufacturers already to start putting it into high end homes.

Questions Class TEST on Monday. Don't drink to much over the weekend - (don't drink to little either)

 

Always a pet peeve of mine--dirty, pitted, scratched w/shield.

Have a 'new' concern now--on my 01 Lightning. Its w/shield has a 'border' of 'haze' (on the outside) along each side from top to bottom. This 'haze' is curved on the inner side--No, it is not from the wipers--not the same curve and further out towards the sides. The haze is about 3" wide. I know this is a confusing description--I just hope you 'glass guys' recognize this condition. Btw, I tried a clay bar and Zaino's glass polish to remove it and neither worked? Any ideas??? Thanks,

Dan

 

Wow so many glass workers!

Lightninrod, what you see on your windshield is residue left over from what they spray on the windshield molds to keep the glass from sticking to the molds as they go through the bending lehrs. Most of the time no one ever sees this, but you must have a windshield that was placed on a mold shortly after being sprayed. A lot of that is covered up by the encapsulation that encases the windshield, which also hides any mold marks. I'm not sure, but I don't think this can be removed. You're supposed to look out the center of the windshield anyway

Bervinator is right about the 97-98 F150 coated glass. It's dipped to get that privacy look. When I had my backlight replaced because of the rain forrest it created in my back seat, they put in glass that is colored, not the dipped type, they cannot get that in aftermarket glass. To the normal Joe on the street, it appears to be the same type of glass, but I noticed a difference right away. The dipped glass is more reflective of images, the privacy isn't. No biggie...but the back window still leaks. Look at the new trucks...window encapsulation like it used to be a few years ago.

Pitting is caused by dirt or glass dust adhered to the ceramic rollers that the glass is heated on as it travels through the furnace. They need washed down often to keep them clean. The waviness/distortion you see on the outer edges is caused by the ring the glass sits on after dropping off the mold and onto the quick sag ring. Furnace operators can adjust this easily to get minimum distortion.

Bervinator is right on the money too with his glass lessons.

I'm ready for the test now...

 

I used a clay bar to take off water spots on my rear window when I sold my shell... it was a lot of work but it did the job.

 

To all you glass experts, I need some help also. MY 01F150 windshield is driving me nuts. I cleaned it three times with Stoner cleaner and newpaper, when that didn't work I tried Windex. What happens is that there seems to be a haze on parts of the outside glass. Its random in appearance. It is especially noticed in the rain with the wipers going, and at night. I can reach around and rub the spots with my fingers. It seems like some kind of oily film. But I can't get it off.

Have any of you ever tried using conventional auto wax on glass? What are the absolute best cleaners? I tried Eagle, Stoner, Windex, but I can't get the glass clean. When new, I did not have this problem.

Any suggestions.

 

I would think twice about using body wax. Won't harm anything but usually makes a big mess.

Dave