[cboy]

I just had the flat glass windshield cut by a local shop for my rat project. It is laminated glass (clearly visible when viewed from the edge) but has no markings or stamp imprinted in the glass indicating it is laminated. I also just checked and the flat glass laminated windshield in my pickup also is not stamped or marked. Interestingly, the rear window of the pickup IS stamped as tempered glass. So I'm a little surprised the laminated glass is not marked as such (for purposes of inspections etc.). The question then is, is all laminated glass equal or is there special automotive laminated glass which IS marked/stamped as such. My local shop knew this glass was going into an automotive application as a windshield and seemed quite knowledgeable about what was required. I'm just a bit miffed by the lack of a stamp on/in the glass.

Dewey

[Beenaway2long]

Dewey,
Laminated glass is NOT stamped. It comes in 5' x 10' sheets generally. If it were stamped, they would have to cut it to size and stamp it separately. Its not EASY to cut like plate glass, but it can be done by the average glass shop.

Tempered glass, on the other hand is manufactured different. The glass is cut to size, then reheated (tempered) and while in the cooling process and the glass is still in a semiliquid state, the stamp is placed in the lower right corner. Hence the additional cost. Incedently, tempered glass is 7x stonger than plate, whereas laminated is the same strength as plate, but will not fracture

Easiest way to tell them apart when broken:

Tempered "explodes" when broke. The largest fragments are about 3/8" square. (side windows, back glass) (A scratch can make it "explode")

Laminated glass: will just "run", but stay together. (think of a stone chip in your windshield, and how the crack runs)

Plate: Large shards, broke apart



Some auto makers WILL mark their laminated windshields as "Safetyglass". This is done when they heat / bend the glass to fit the opening. Flat glass is generally not marked, but is the same strength.

[cboy]

Thanks Beenaway. I'm cookin' then.

Dewey

[wheel-7]

All automotive laminated glass in the U.S must meet the same performance standards. The glass is laminated with a product called PVB. ( Polyvinylbutryl Resin ) sheeting. The sheeting is approx. 030 thick.The product is purchased either clear or with a tinted shade band. The largest producer of this product is DuPont.
Back in the 50's the U.S govt. required all new cars and all replacement windshields to have laminated glass. The side and rear windows can be tempered glass. That brings up the question: Why not laminated the side and rear glass ? Good question, no logical reason not to.Would be excellent against car jackings, theft, and most importantly preventing people getting thrown through the side glass or out the back glass.Or, having a zillion tiny pieces of glass flying around inside the car on impact. The car companys have elected to go with side air bags?? The sheeting maybe expensive or??
Starting to see alot of laminated glass in homes and bldgs. now

[cboy]

Originally Posted by wheel-7

All automotive laminated glass in the U.S must meet the same performance standards. The glass is laminated with a product called PVB. ( Polyvinylbutryl Resin ) sheeting. The sheeting is approx. 030 thick.The product is purchased either clear or with a tinted shade band. The largest producer of this product is DuPont.

So is there laminated glass made that does NOT meet the automotive performance standards and if so, how do you know if your glass does or doesn't conform? I have no reason to believe my shop didn't do this right, since I was clear this was for a windshield and they were recommended by the body shop I use, but I'm curious how you can tell the difference if the glass is not stamped or identified in some other way.

[baddbob]

Originally Posted by cboy

So is there laminated glass made that does NOT meet the automotive performance standards and if so, how do you know if your glass does or doesn't conform? I have no reason to believe my shop didn't do this right, since I was clear this was for a windshield and they were recommended by the body shop I use, but I'm curious how you can tell the difference if the glass is not stamped or identified in some other way.

Laminated glass when viewed from the edge you can see the two ply.

You'd be glad safety glass isn't used on side windows if you ever had to break one to get out.

[TooMany2count]

You'd be glad safety glass isn't used on side windows if you ever had to break one to get out.

some SUV's use laminated glass for the side windows. at least the ones in the rear doors & sides of my 84 burb are &&& almost EVERY car made back in the days of "REAL STEEL" (sometime in the 50"s & back) had laminated glass for everything but the rear windshield

[wheel-7]

How do you tell if its laminated ? Just like Badbob said..You'll see the vinyl interlayer between the glass. PPG is by far the largest producer of replacement glass in the U.S. Maybe, the world? They have a big share of the new car market also. I would think that both DuPont who sells the interlayer of vinyl and PPG who laminates the glass would have a zillion quality tests before they could even sell it.
True, alot of SUV's and vans have laminated side glass.Mostly the dark colored "privacy " glass.
Toomany too count is right that back in the day alot of cars had laminated side glass and windshields. I have two 53 Studebaker coups and both cars have laminated glass all the way around.
For my two cents I would have laminated glass all the way vs. the side air bags.

[cboy]

Originally Posted by wheel-7

How do you tell if its laminated ? Just like Badbob said..You'll see the vinyl interlayer between the glass.

Why am I getting answers to a question I never asked? Please re-read my post. The question is NOT and NEVER WAS how you tell if glass is laminated. My glass is obviously laminated. The question was, if there are standards for automotive glass (as noted by wheel-7), and if laminated glass is made which does not conform to those standards, how do you know if YOUR glass is correct for an automotive application, given the fact that laminated glass is not stamped or marked in any way.

[Beenaway2long]

Relax Dewey..... All Laminated glass is PVB. Your OK.


Check this site out

http://www.safetyforum.com/glazing/

Do a google search with keywords "Laminated Glass Automotive" or "Laminated glass types"


Net result: The glass guy didn't give you a bum steer. Its fine.

As far as the laminated side glass... I'll take tempered side glass in a heartbeat. One study showed out of 117,000 accidents with glass lacerations, 100,000 were from laminated windshield, whereas 17,000 were from the tempered. Easy to pick out dull pieces, than pull out long shards.

Why does the automakers use tempered in sides and back? Simple. Cost. To temper (1) shaped piece of glass is MUCH cheaper than to take (2) pieces, 1/2 the thickness and mold them, then intersperse the PVB binder. Higher breakage. This explains why only the high end guys are doing it. Partially as a result of the insurance industry, to get breaks on theft insurance. Laminated holds together, whereas the tempered "explodes" into little squares.

Interesting fact: Look at broken glass.
Tempered breaks into small squares with no "sharks teeth" so to speak
Laminated will "Star" at impact point, and release sharp pointed shards with "sharks teeth" (although the PVB does its best to restrain them. Look at impacted/broken laminated glass to see what I mean.

"Sharks teeth": Look REAL close. When cutting annealed (plate or laminated) glass, you will see the edge will have a bevelled top from the cutter. The bottom will show tiny fragments from where the glass fractures. The fragments will resemble a serrated knife. That is why you have to squeeze the glass between your finders when carrying it. If it slides, it will slice you. If the edges have been ground or polished, you won't see them.

Ever have a piece of plate glass "just break"? Its a result of the sharks teeth, where the serration went too far into the piece. That weakened the glass there.

[cboy]

Thanks for the info Beenaway.

As I re-read my post I think I was having one of my cranky days there. Thank goodness Dorothy upped the dosage on my meds. Hope I didn't offend you.

Dewey

[THE GLASSMAN]

Laminated safety glass is manufactured in several catagories of application.
Firstly, if the car in question is to be registered for road use it must be stamped "AS1 laminated", that is too say the windshield is distortion free,and meets all federal safety standards.
AS2 laminated glass is of the same thickness,but is not distortion free.
This rating is however legal for use as a side lite,or rear vision.
AS3 laminated glass is comprised with a thicker interlayer .060 and has an accoustic deadening property, it is also NOT distortion free.
P.S. the stamp is also required for NSRA registration