OT - automotive windshield replacement - urethane bead style questions

On Wed, 27 Oct 2004 23:17:42 -0400, aribert calmly ranted:

I used to help the glass man R&R glass at the body shop, but that was back in 1980-85. Other than the heated window wiring, the glue-ins should be roughly the same. When you use the heated cutter to remove it, make sure you leave an absolutely flat surface to rebond to. On some vehicles, that meant cleaning out all the old adhesive. On others, he left a healthy amount. I never did figure out his exact reasoning, but I think it had to do with body flex, and he left more in smaller cars whose bodies moved all over the place.

When you're done gluing, you want absolutely no initial stress on the glass or metal contact, so don't press it down too firmly. (You can hit sheetmetal.) If the vehicle you're setting it into doesn't have plastic/nylon guide blocks at the bottom (or sides), you can use oiled wooden blocks to center it. The adhesive won't stick to them.

Look for a good, even "black" edge of contact all the way around the glass to make sure it is sealed completely. The adhesive cartridge should have full instructions on its use (wet or dry seal.)

We had more fun with the rope trick than those sticky glues. I still can't believe how hard he hit those pieces of glass with his open palm, though. They're quite strong, but...

I was told by a glass man that in any of your newer cars the windshield is a structural part of the vehicle. Any time he does a windshield on a newer vehicle he does not move it for over 24 hours to let the adhesive set.

if there is any stress on the windshield, make sure you get the two glass primers and use them in sequence - there is a clear primer you put on, then wait 3 minutes and put on a black primer - they come in one time applicators for about $3 each from 3M. I found that without the primer, adhesion was very poor (this on a rear hatch) and the glass separated in two weeks.

"Arthur Hardy" wrote: I was told by a glass man that in any of your newer cars the windshield is a structural part of the vehicle.(clip) ^^^^^^^^^^^^^^ IOW, when the car hits a bump the windshield helps keep the body rigid? I think the old way was better--let the steel do the job.

I'm currently facing the same possibility with my wife's '93 Buick Century. A small ding at the left base of the windshield has caused a crack to appear.

But isn't it possible to drill (?) a hole at the end of the crack, reduce the stress to stop it from spreading, and fill it with some kind of epoxy? Or is my memory playing tricks with me again...

Chet

On Thu, 28 Oct 2004 16:55:22 GMT, Gunner calmly ranted:

-snip-

That means one of 3 things, the first two being the most probable.

1) Your (truck?) body is flexing more than it should, creating too much stress on the windshield. Rusted out bottoms usually account or that, but missing body mount pads can also cause it. Since you probably off-road it a bit, that increases the flexing.

2) Your body is bent (specifically the windshield pinch weld) and the installer tried to bend the glass to fit. Poorly done repair work after an accident is the normal cause of this.

3) The glass was nicked there before or during the installation.

None of those is good for glass life.

On Fri, 29 Oct 2004 10:41:00 -0400, "Chet & Audrey Roberts" calmly ranted:

Google on "windshield repair" and you should find something, Chet.

The guy at the shop that sold me the windshield and adhesive for my truck, gave me a pointer or two. mostly he said to cut the end off the applicator nozzle at just about a right angle, then cut a large(ish) V notch in the side of the cut-off end. The nozzle then leaves a sharply peaked, consistent bead of adhesive.

He said to align the glass at the bottom, and basically to let it drop onto the sealant bead. After all was in place, and settled into it's final spot, he said to spray the area with a bit of water, as the moisture kicks the cure of the adhesive.

Worked for me. Windshield is 4 years and a bit old, and would be in pretty good shape if I had not been hit by a flying grouse a while back.

Cheers Trevor Jones

No rust. The only time it leaves the pavement is when I back it into my 20 foot long drive way.

The glass laid perfectly flat on the very large bead of caulk he laid down. I watched carefully.

Neither is simple Kharma.

Gunner

"By calling attention to 'a well regulated militia', the 'security' of the nation, and the right of each citizen 'to keep and bear arms', our founding fathers recognized the essentially civilian nature of our economy. Although it is extremely unlikely that the fears of governmental tyranny which gave rise to the Second Amendment will ever be a major danger to our nation, the Amendment still remains an important declaration of our basic civilian-military relationships, in which every citizen must be ready to participate in the defense of his country. For that reason, I believe the Second Amendment will always be important." -- Senator John F. Kennedy, (D) 1960

On Sat, 30 Oct 2004 12:22:58 GMT, Gunner calmly ranted:

If it was laid right, there's no flex, and it wasn't nicked, check with the glass man and his supplier/mfgr. There may be a flaw in their design and they might replace it free.

If not, it's your Shrub-voting karma, dude. ;)

Its probably the Karmic issues with being forced to follow gravel and construction trucks over the same stretch of road a couple times a week for years.

Gunner

"By calling attention to 'a well regulated militia', the 'security' of the nation, and the right of each citizen 'to keep and bear arms', our founding fathers recognized the essentially civilian nature of our economy. Although it is extremely unlikely that the fears of governmental tyranny which gave rise to the Second Amendment will ever be a major danger to our nation, the Amendment still remains an important declaration of our basic civilian-military relationships, in which every citizen must be ready to participate in the defense of his country. For that reason, I believe the Second Amendment will always be important." -- Senator John F. Kennedy, (D) 1960

On Sun, 31 Oct 2004 01:57:07 GMT, Gunner calmly ranted:

Then why are you surprised that it's cracked? That's what cracked my windshield last year. I may get it fixed some day. The 1" gravel hit below the center of the left wiper blade and lefta star half an inch in diameter. In 3 days, it had crept right a few inches and up an inch. A week later, it had made midpoint. The next time I washed the truck, I noticed that it had made it all the way up to the top, vertically, that morning. I guess the cold water was too much. Ayup, it's time for new glass. Only $189 here, installed. Ugh!

I was a bit surprised that it cracked in the exact same fashion and and the exact same place and the crack went in the exact same direction to the same destination.

Id gotten used to the first crack and it was like being home again when it happened the second time.

Gunner

"As physicists now know, there is some nonzero probability that any object will, through quantum effects, tunnel from the workbench in your shop to Floyds Knobs, Indiana (unless your shop is already in Indiana, in which case the object will tunnel to Trotters, North Dakota). The smaller mass of the object, the higher the probability. Therefore, disassembled parts, particularly small ones, of machines disappear much faster than assembled machines." Greg Dermer: rec.crafts.metalworking

On Sun, 31 Oct 2004 10:24:22 GMT, Gunner calmly ranted:

Unless your and their driving habits, roads, and vehicles have changed, why would you think it so odd? Shouldn't you have learned to avoid following closely enough to get hit?

The one which hit me came from the other side of the road on a curve under the I-5 overpass at Exit 55, so I know they can come seemingly out of nowhere.

But that sucks, doesn't it?

LJ --with a 3-star windshield.

Given the description of the crack, it is EXTREMELY unliky it is caused by an impact. It is a classic stress crack, or an edge chip fracture.

This windsheild should be replaced by the installer at no cost under their standard installation warranty, and the cause investigated.

If the windsheild edge touched the wiper post, for instance, while being installed, the minor scratch/chip that resulted WILL eventually cause the windsheild to crack.

If there is a sharp "tit" on one of the spotwelds on the "pinch", and it was allowed to touch the edge of the windscreen, it will cause the windshield to crack. Or possibly the trimclip that holds the windsield trim. Most glass shops today do not properly install the retainer clips, they just stick them into the uncured urethane and let them cure in, effectivel gluing the trim on. If a trim clip is too close to the glass edge, any minor flexing will crack the glass.

THanks for the posted replys and also to "actualnamenospam" who sent me a long descriptive e-mail.

aribert wrote: