What is "glazing"?

[Anonymous]

I have seen references to "glazing" on passenger cars, and was wondering if anyone could explain to me what it is.

Thank you very much for your help.

Most sincerely yours,
Daniel

[Anonymous]

Hi Daniel--

Glazing refers to the glass windows on the equipment. It's sort of an archaic term, but still used in the architectural and window business.

Glazing on current RR equipment has to meet the federal requirements in 49 CFR 223, which have to do with resistange to breakage and impact. So when you hear someone refer to "Part 223 glazing", that's what they are talking about.

Hope this helps

[Anonymous]

Dear drephpe,
Thank you very much for clearing that up.

Does this mean that glazing is something added to the glass after the glass is formed?

Sincerely,
Daniel

[Big_Boy_4005]

No, no, it's just the term used for glass in general. A person working in a glass shop would be called a glazer, just like someone working in a bakery would be called a baker.

Glazing is the glass. Passenger cars have special safety "glazing", like Drephpe is talking about. I believe it is similar to that which is used in cars, only heavier. The glass is actually sandwhiched between layers of plastic, to keep it from shattering in an accident.

This question is really more a job for your dictionary.[swg]

[Big_Boy_4005]

Oops, sorry Mark, you're right. The sandwich is the other way, glass on the outsides.

I think the term has been changed to "bullet resistant", as bulletproof was considered misleading. [swg]

[Anonymous]

Glass...

LC

[dharmon]

Aircraft windows are made in the same manner, with layers of plexiglass and glass usually two or three ply. Over time, the continual changes of pressure and temperature, up to 60-70 deg in a matter of minutes will find the flaws in the window and it will begin to delaminate, creating bubbles between the layers. At that point it is really only a matter of time before it fails. As Mark points out, the glass is there to minimize scratching. If you notice airliner passenger windows, they are usually fairly scratched up and crazed. That's a plexiglass or poly carb window. But in the big scheme..who cares and they don't have the same issues as bonding glass and a poly. A windscreen will be clear and frequently polished with glass cleaner. That is also one of the huge problems with bubble canopies on fighter jets. The actual windscreen is a glass plate, but the bubble is a poly. It requires frequent and cleaning polishing to keep it clear. Probably more info than you wanted.

[Anonymous]

Dear Mr. Hemphill, Mr. Feinberg, Limitedclear and dharmon,
Thank you all so very much for clearing that up for me--I think I now understand it.

Most gratefully yours,
Daniel

[Mookie]

QUOTE: Originally posted by M.W. Hemphill

Wait! We have hundreds of lines of irrelevancy, tangential argument, and backbiting still to add!

Well, at least we got the humor out of the way!

[:)]

Mook

[tree68]

Glazing - what my eyes do sometimes....

Look around your local hardware store sometime, in the glass section, and you will find "glazing compound," used to seal the glass in the window frame (simple explanation.)

The plastic in your windshield (which is between two layers of glass) is there to prevent something hitting the windshield from coming all the way through (or you from going out, if you have an accident and neglected to fasten your seatbelt). If you score and break both sides of windshield glass, the joint will flex. Common alcohol can then be used to disolve the plastic and complete the "cut". By itself, the plastic would be of little use as a window.

An extreme example of the hazing that occurs between the layers can be seen at "The Henry Ford," in Dearborn, MI, where several presidential limos are on display. The windows of the Reagan limo are completely frosted over - the result of the phenomenon Mr Harmon speaks to. There is a placard at the display explaining why the windows are "frosted. "

[Modelcar]

....And to add some of Mark's above descriptions....Double glazing [laminated], on late model autos is not as complete now as it was years ago. Most of auto glass [side windows], now is tempered glass. But some are even double glazing as in storm windows...Mercedes for example.

[jchnhtfd]

and for those (limited!) few who worry about the condition of the windows on passenger aircraft... that scratched, hazed, and otherwise horrid looking layer you see on the inside is there mostly for thermal insulation, and to keep the passenger's hands etc. off the actual window, which is flush with the outside skin of the fuselage and is laminated glass as the folks above have been mentioning. It's that outside window (which you can't touch!) which keeps the pressure in the airplane (and, not incidentally, you in the airplane, too...)

[dharmon]

I know of cases where a small hole abruptly turned into a big hole, but to suck someone out it's going to be a big hole. There was another incident I thought of which was a UAL flight in the Pacific, where the cargo door came off, causing a big hole and a whole row or two of passengers was ripped out. They lost two engines due to debris but landed safely. But all the cases have been big, sorry BIG holes.

Now as far as RRs go. There was a big change in the requirements for locomotive windows in the 70's ???. Many of GE Uboats had that had the oval windows on either side of the cab side windows were plated over. I presume this was to avoid cost of replacement with safety glass.

[Anonymous]

QUOTE: Originally posted by tree68

Glazing - what my eyes do sometimes....

Look around your local hardware store sometime, in the glass section, and you will find "glazing compound," used to seal the glass in the window frame (simple explanation.)

I have to agree with Larry. I thought that glazing was the putty that held in the window and a glazer was a person who installs the glass in the window frames??

[WDGF]

QUOTE: [i]The only time I know of that someone was fully sucked from a plane was Hawaiian Airlines 737 that had a fatigue failure and the stewardess ..not strapped in went out.

Here's more than you ever wanted to know about this incident:

http://www.disastercity.com/ghost/

http://www.aloha.net/~icarus/

Not pretty, but amazing to me that this aircraft was able to make it "safely" back to ground.

[Modelcar]

....Always did think the sucking people out windows in aircraft...especially in movies, was bunk....And reading all of the above I still do. Believe that cargo door being ripped off over in the Pacific was on a 747 and it removed enough of the structure adjacent to where the seat rows were they went out without question...

[dharmon]

QUOTE: Originally posted by Modelcar

....Always did think the sucking people out windows in aircraft...especially in movies, was bunk....And reading all of the above I still do. Believe that cargo door being ripped off over in the Pacific was on a 747 and it removed enough of the structure adjacent to where the seat rows were they went out without question...

The 747, 737 and C130 cases are all documented. There are probably a few more. But as Mark points out..it needs to be a big hole. And the altitude ie.. pressurization differential needs to be high.

[dharmon]

But more to the topic of "glazing".............

Glazed over is what the bear was that they found in WA on the news today that consumed 36 cans of Rainer Beer!!!

[Anonymous]

All windows in an automobile are tempered glass only except the windshield which still is the laminated glass. The two sheets of glass that are laminated together are tempered glass. Tempered glass is heated to near ists melting point then quickly cooled by air jets. As we know when an article cools it shrinks. The surface cooling faster than the insides of a piece of glass places lots of strain on the surface which makes it resistant to shatter. We are all familar with the breaking of a standard single glazed house window. The broken pieces are like long knives and act that way. No one wants this in an auto or train which could kill or severely cut people. Tempered glass, due to its nature, will shatter into pieces no laeger than 1/4 inch which greatly minimizes the severe cutting potential. We have all seen the reminants of a broken car window at the scene of an accident. Household shower and patio doors are made of tempered glass to reduce the sutting risk. I have seen a demo where a patio door glass panel was placed between a couple of 4x4 boards. A person would stand on the glass and it would flex. Then he would chip the edge with a hatchet. The small chip in the glass released the internal energy and the pane would shatter to the 1/4 inch pieces.

[Mookie]

QUOTE: Originally posted by dharmon

But more to the topic of "glazing".............

Glazed over is what the bear was that they found in WA on the news today that consumed 36 cans of Rainer Beer!!!

dare I say this on a public forum?

Did you hear about the newlyweds that got the window putty and something else mixed up?

Their windows fell out?

[:I]

[tree68]

QUOTE: Originally posted by wrwatkins

. A person would stand on the glass and it would flex. Then he would chip the edge with a hatchet. The small chip in the glass released the internal energy and the pane would shatter to the 1/4 inch pieces.

Which is why you will have problems breaking car windows with a baseball bat, but the neighbor kid with his BB gun will air condition your car in a second. Firefighters and EMTs often carry small "automatic" center punches to take out the side and back windows of cars. Some car thieves carry them, too...

[dharmon]

QUOTE: Originally posted by Mookie

Their windows fell out?

[:I]

So their computer doesn't work anymore?

[Anonymous]

Thanks Tree68 for yor comments. I think all of the Amtrak and commuter rail cars have small pointed hammers just to break out windows. It is sorry that some of our not so outstanding citizens have them also. Hopefully at the iron hotel where they belong the hammers will be useless.

[Anonymous]

You know, about a week ago I saw the movie Airport on TV [:)].