Windshield Repair Forum

I'm just curious about this subject.

Yesterday and today I had to small crack repairs on both SGC windshields in Altima's. The repair yesterday was very tender to the touch and today's was by far much worse to work with. By tender, I mean that it was very easy to spread.

Yesterdays had cracked 5" overnight and started to crack even more as I began to drill.

the repair I just came from cracked as I started to drill and continued another 3" within a few minutes. I made another drill hole and this time caught it, made the bullseye and began to fill. I then covered it with the UV screen and focused on the other side of the crack that was beginning to walk away as well. I got that side stopped and fixed only to return to the other side and find that it had cracked again about 5". Yes, very frustrating.
As I touched the drill to the glass, it again cracked another 2". This time I didn't make a BE to stop but instead just wicked in the resin and it all stopped.


I'm sure that someone else out there has experienced the glass being stubborn this way or in a similar way. It would be very nice to know how much this is happening and what techniques people are using.

Also, SGC stands for Safelite, correct?

Thanks

Most aftermarket glass is not difficult to work on however Safelite glass is not known to be very good glass. I understand that before the went bankrupt that the problem with their glass was that their glass kilns were not being fired up hot enough. This caused the glass to be more brittle than other brands. Had a Safelite salesman tell me that several years ago that their glass was not very good quality.

How hot was the glass.

Also you should use UV shield before you start to fill.

For those doubters place a small amount of resin under a piece of film and time how long it takes to thicken, let alone harden.

This resin will scrape off easily, of course do this away from the damage.

This will also show you how much indirect effects our work.

both screens where cool to the touch, so less than body temperature. The temp the last two days has been in the mid 70's as well.

On the one repair today, I had the UV screen on and under a towel to try to keep heat and sun out. I seemed to have more than enough time to work the resin. I say that because it didn't cure on me before I was done. It was just that the crack would run even after a bullseye was popped or would run right past as soon as I touched the drill to the glass. I will say that it was a god thing the customer was there to watch it run away from me. He thought it was very interesting but was extremely glad that I was able to stop it.

My guess would be that the glass was under stress from the installation.

3 possibilities 1) at 70 Deg the PVB interlayer will be soft & yielding allowing any stress in the glass to be transmitted more easily. 2) the type of glass used to Mfg. the windscreen could be of 2 types i.e. sheet/automotive quality or Float quality the latter being the best. 3) the windscreen you were working on had a high curvature, making it more difficult for the maker to get a good laminate and more heat when the glass is on the drop frame during manufacture therefore an increase chance of stress cracking. e.g. the old Saab 99 windscreen was well known for stress cracking and delamination.

SGC shields frequently don't fit the pinchweld worth a darn and the lites are thinner than OEM glass. The combination of these factors makes these shields very "sensitive". When they are installed they are essentially "bent" into the pinchweld which creates a ton of stress on the glass. Usually when the get hit by a rock they split immediately.