First Breakout

[Bois]

I had my first windshield breakout this morning. It wasn't fun. Maybe someone could help me understand the forces at play so as to minimize and/or foresee this in the future.

Here's the specs:
- bulls-eye just below wiper blade with 2" crack down to edge of glass and 6" crack leading up the glass.
- temp around 50 degrees (F) with full sunshine.
- had customer pull car out from under carport for sun to warm screen (still cool from night) and to shed light on the break.
- windshield was a replacement. Replaced in 10/2004.
- I was using Delta Kits bridge & injector with GT LV resin.

Process: I drilled a hole at the end of the 6" crack and popped a small bulls-eye with probe. A 1/2" crack appeared above the new bulls-eye. I proceeded to mount the bridge assembly to fill the original bulls-eye and fill the crack. I then mounted my 2nd bridge assembly to fill the bulls-eye that I made assuming that the 1/2" crack would seal like any other small leg. Wrong! When I mounted the second bridge, the 1/2" crack spread another 1/2". So, I drilled again and popped a bulls-eye. When I did, another 4" crack appeared. :eusa_doh: I drilled a 3rd time and another crack appeared - all traveling in the same direction across the WS. :eusa_wall

Frustrated, I filled all the holes with pit resin and informed the customer that the WS would have to be replaced. :icon_redf The customer was not upset since she had gone through this once before and her deductable was only $90. :eusa_whis

NOW! Thoughts. 1) maybe I didn't drill far enough ahead of the cracks? 2) maybe the replacement glass was below par? 3) maybe the stress was too great to begin with? 4) what else...

Dale...

[GlassStarz]

It was already cracked out so dont sweat it.
I would have put injector on original break run a bead of thin resin along crack covered with cure tabs. Slowww pressure while under uv protector, all the time watching the end to make sure it isnt moving remove uv protector let cure with sun for a while with injector still in place then go to the end drill give it a minor pop then apply second injector.
A stablized crack on one end is less likely to run on the other. Also I think i wouldnt have tried to warm it colder glass seems to be more stable and cold glass opens the crack to let the resin in. Cold shrinks hot swells (Just like in the shower ) )

[ACT 1]

Dale: you indicated that the crack went to the bottom edge of the shield 2 inches and up 6 inches. In my short career as a windshield repair tech I have operated with the understanding that we could not repair shields that were cracked to an edge. I have passed on jobs that did run to an edge thinking that this was the appropriate thing to do and therefore I have never attempted such a repair. Is it common to do repairs that run to an edge? And can we guarantee the work??? I am confused some enlightenment would be appreciated. ........... Tom

[Dave M]

My guess would be that you did not drill far enough away from the end of the crack. Before you drilled did you apply lite pressure on the end of the crack (from the inside) to see where the end of the crack was?

If you drilled on top of or behind the end of the crack, when you attempted to pop the mini bullseye the pressure from the tap extended the break.

[paintlessplus]

Bois, You might have done everything right, its hard to say, sometimes you just can't overcome instability in glass. My only recommendation is to get really good at drilling precisely.

I always put my inspection mirror on the inside to get a good referrence point to start, it helps to center your bit placement. I drill to a point on my mirror and not at a point on the glass. I also use a magnifying glass. I drill using a circular motion and pop with my deltakits probe and tap the bull with the suction release stick.

I like to make sure that on breaks like the one you describe that the customer is aware of the fact that it will be a very tricky repair to pull off, then when you succeed you look good - if you don't, they aren't surprised. I also prefer to have the customer watch when I perform these if possible, it gets them involved and aware. Bob

[mafsu]

I believe the edge cracks most people refer to not doing are stress cracks. I have never had a problem with fixing cracks that ran to an edge as long as there is a visible impact point.

[Repair1]

Bois,

Well welcome to the repair business, you will break a few windshields occasionally that

[Bois]

Thanks for the feedback, guys.
I suspect that I didn't drill far enough ahead of the crack. And, as I recall, I didn't use the probe to test for the crack's end.

As for repairing cracks at the edge... I've done several where the impact point was visible (2" from edge) and legs ran about 2" in various directions.

I need to get some practice glass from a shop as mentioned in Jeff2's thread.

Dale...