Break on inner side of inner lite

[Brent Deines]

I just received a call from a customer who worked on a very odd break. Although I have seen this type of break I don't recall ever working on one, so I thought it might make interesting conversation if nothing else. I believe the damage was on a heated Land Rover windshield, was down in the frit band (black area) at the bottom of the windshield, and was a very large combination break. The longest crack was about 4" long and extended up toward the center of the windshield. Obviously this is an expensive windshield ($1000+) so the customer was not so much concerned with cosmetics, but just wanted to keep it from cracking out.

Okay, so all nothing too unusual so far, but here's where it gets fun. There was an impact point on the outer surface of the outer lite of glass, but the majority of the damage was on the inner surface of the inner lite of glass. To avoid confusion let's name the surfaces. The outer surface of the windshield is #1, the inner surface (next to the pvb) of the outer lite is #2, the inner surface of the inner lite (next to the pvb) is #3, and the inner surface (inside the vehicle) of the inner lite is #4. A lite is a sheet of glass, and pvb is the laminate material sandwiched between the two lites of glass. Every windshield is made up of two lights of glass and one layer of pvb, therefore there are always 4 surfaces of glass that we have now named. Alright, enough of windshield construction 101, now on to the damage.

So the majority of the damage was to the #3 surface and did not go all the way through to the #4 surface. Therefore the damage was not accessible by conventional methods.

There are several challenges here, including but not limited to, heated windshield with grid system to conduct heat, access to damage has to be done by drilling through #1, #2, and laminate, or through #4 surface in which case you would be working upside down from the inside of the vehicle.

How many of you have seen this kind of damage, and how many have attempted to repair it? What kind of results did you achieve? Should it be repaired?

I'll interject my thoughts but would like to hear from some of you first.

[Frank EU]

In some fifteen years, as far as I know we had this only once. In fact it was fairly recently. It happened at home (Europe). Since I currently stay here in the US, I speak from my memory. I cannot recall the vehicle details, but is was NOT a truck, bus or coach -that's for sure. If needed I wil look into it and let you know in some two weeks from now. We did NOT attempt to carry out a repair -since the damage was on the inner layer.

[Dave M]

I have never seen this type of damage. That being said, we all know Land Rover w/s are very expensive. I would recommend the customer replace this w/s hopefully through their insurance company.
My reasons are simple...paragraph 7-----7.1,7.3 and 7.6 of ROLAGS.

[screenman]

I would not do this repair on this particular vehicle, although I have carried out repairs like this on large truck screens. More than likely the cracks will be surface cracks on #4 so capilery action would likely work, curing would be a problem with so much of the damage behind the glass.

I seem to think and correct me if I am wrong that a repaired are should be stronger than the surrounding glass itself. If this is correct then a repair through the laminate should be acceptable.

Me opening a can of worms again I expect.

[SGT]

I have never seen this type of damage either. Like Dave M. mentioned, if you hold yourself to the ROLAG standard you should decline the repair as I understand it. If you do not practice the standards limitations, well then there will be no one coming around the corner to stop you.

If you were to make an attempt to repair...with the damage in the frit area at the bottom of the windshield, If I recall correctly the space between the glass and the dash is minimal, how would you get your tools setup to do the job?

[Brent Deines]

Screenman, the damage did not go through to the #4 surface. The technician who made this repair actually drilled through the laminate and into the #3 surface enough to inject resin into the crack. The crack filled back an inch or so, but not all the way. This will likely terminate the crack which is all the customer was interested in, so as I understand it the customer was happy.

I would not have recommended this repair for the reasons already mentioned, but in this case the customer said he would be replacing the glass if the repair did not come out well, so the technician saw it as an opportunity to try something that he had not done before. I have repaired some #4 surface damage for the same reason in the past for the same reason, but I don't recommend that either. In my opinion any windshield with #3 or #4 surface damage should be replaced, but it's always fun to see just what you are capable of, and that's how new techniques are sometimes born.

In cases like this I will not attempt the repair on the customer's vehicle, but will ask if I can have the damaged glass after it is replaced to experiment on. That way I have no liability but still get to test my skills.

[screenman]

Thta is incredibly unusual for damage to the inner layer not to come through even very slightly in fact in all the years I have been repairing glass I have never seen a case when it did not. As we know when glass breaks the PVB stops the the shock and hold the broken pieces in place. I am going experimenting right now as I have just finished training a guy to use a delta Kits and I have a practise screen set up. Protective clothing is called for and a big hammer. Sorry Brent I just cannot understand how the inner layer would break without it going through even very slightly, for the glass to break it must have been pushed back, thus causing the #4 to stretch and break if only very slightly. I will let you know how my experiments go.

[Brent Deines]

I agree that it is unusual and I can't explain it, but I have seen it. I just have not ever attempted to repair it. I have to admit that I did not see this break, so I am only going by what I was told, but I have no reason to doubt the customer who I believe is knowledgeable enough to know if the #4 surface was compromised.

[screenman]

I now have a very mashed up windscreen, sure takes some hitting to break both sides, still got surface breaks on #4 though, I do not doubt what you say, I have just never experienced it and logic cannot explain it so that confuses my simple brain cell.

The Landrover screen to my knowledge does not have frits are we talking Range Rover? where mots of the frits are behind the dash?

[Brent Deines]

It may very well have been a Landrover, I always get the two mixed up and frankly I was not taking notes, so I'm just trying to repeat what I can remember from the brief telephone conversation.

I have trouble just trying to make bullseyes, stars, and combination breaks that are limited to the #1 & #2 surfaces, so good luck trying to create this one.