Stumped!?!

[MadMike]

Last Monday! I went out to my car and to my surprise I had a 14" Crack in my WS. It started way low, right on the edge, passenger side, with up for 4 inches and turned towards the middle. I didn't even remember being hit, the impact was extremely small.

I don't normally do long cracks, so, I took it as an opportunity to practice on my own vehicle.

So I popped a mini on the end, ran it into it, filled and cured. Looked great! Then I filled from the bottom, It filled in really good and seeped up all the way to to the top at the turn, (about 4 inches). Then I did the seeping in along the long part of the crack, it all filled in really nice. About 90% better. Curred it all and it looked great.

Well we got a lot of snow Sunday Night, and all day MOnday. Temperatures dropped down extremely low over Monday night! Nero zero!

Tuesday morning the crack grew about 6" all by itself, and the part I filled and cured looks like it was never repaired. Except for maybe the first 3 inches above the impact point!

What happened! I did everything right! There was never any moisture introduced before I did the repair. I followed all the rules!

I haven't attempted a new repair yet, wanted some input first before I blew it again.

[Dave M]

MadMike,

Without actually seeing how you performed the repair and in what type of weather conditions you were in at the time of repair, I would be only guessing.

My first "guess" would be miosture. If you've had cold temperatures where there has been frost, condensation or snow, moisture could have expanded in those extreme cold temps and re-opened the crack.

How long did you cure? Was the crack a surface or sub-surface break? Was the glass too cold to attempt the repair?

Cracks in cold weather can be a pain the ...!

[MadMike]

At the time that I did the repair, the temperatures were ideal. WS was just warm to the touch. There was no rain, or heavy dew the night before or the morning before I did the repair. Which I did about 11 am. I cured the very end and the impact with a uv lamp and let the sun cure the middle, since I didn't have a long lamp. I gave the sun ample time, about 15 minutes. Up here in the Colorado Rockies at 8500 feet the UVs are a little more intense than at lower levels.

Surface and sub-surface are new terms for me. But, hey, I would assume that surface means I can feel the break on exterior which was the case. I was able to fill the crack from the surface by placing drops of resin on the top of the glass, and just letting it seep in.

I really want to attempt a new fix on my "NOW" 20" crack.

[Coitster]

Hey Mike,
You have having the problem that most people have when they repair long cracks. Usualy it is caused by the fact the resin we use in chip repair is not strong enough for long crack repair. As the windshield cools down or heats up the bonds holding the resin in place usualy break down and the resin isn't able to hold on. A long crack has mach stronger stresses then a chip. Sometimes up to 10 times the amount. Thats why many companies stress selling different viscosities of resin for long crack repair.

Some companies recommend using extreamly thick resins. Some of them will sell you 3 to 5 different thicknesses and the reasoning behind their thinking is because its thicker it is more dense molecularly. Is this true, their cold be some truth to it. I am not a crack repair expert. I have done plenty of crack repairs and when I do use some thicker resins they do a little better of a job but its also very important to get to a crack as soon as possible. Because the longer you let it go the more dirt will get into it and you can't clean dirt out. Granted your's was brand new so I don't have a clear and decisive answer for you but it was probably the resin you used. Some are just not ment for crack repair. I know that Delta Kits doesn't recomment long crack repair but I for one have used Delta Kits equipment on long cracks fairly often and like it.
David
Coitster

[MadMike]

Thanks Dave, Good insight!

I'm Delta all the way. And used the resin that normally comes with there kit.

Its about 20 inches long now! I'll be attemting the repair again tomorrow. After a good 2 days of ensuring no moisture is in it, I hope it holds up.

At least its my own WS I'm practicing on.

I too have been shying away from the long cracks. Too many variables to long cracks to be confident with it. Atleast for now, In a year or two I might be singing a different tune!

[glassdoctor]

Your "experiment" is a good example of why I seldom do any cracks. I would rather do regular repairs, of which I have a 0% failure rate.

Cracks is like craps... a roll of the dice.

[MadMike]

Good point GlassDoc, I have done a good job staying away from them myself. I just wish that I could atleast stop this one, since it is on my own personal auto. Heck, I just had it replaced about 5 months ago. Its a drag, I gotta do it again at $200 bucks a pop.

I hate driving around doing business with a big ol' crack in my windshield. I reckon I should bite it and get it replaced.

[glassdoctor]

I know there are guys that swear all their crack repairs are perfect, etc. Or that brand X resin never fails...

Truth is, sometimes cracks don't hold. I don't think it's just the resin. I use what I feel is great resin. I admit I have not tried all those "best crack resin in the world"... so maybe there is a better resin for cracks than what I use. I'll probably never know.

I have seen crack repairs hold up great. I have seen them fail after several months of looking good. I have seen some fail shortly, like yours.

They always look good when the repair is done and cured well. But in the back of your mind, you know that there is a reasonable chance that any given crack repair will fail.


Let us know what happens after round two... and if neccessary, round three....

[glassdoctor]

Oh, btw... I have seen a couple guys over the years come around my cash cow of dealerships, proclaiming the salvation of all broken windshields.

"I can do cracks! I have the special crack system! You don't have to replace them any more! I am here to save the day!!!!!"

Guess what? They dissapeared faster than snow in June....

Apparently nobody was impressed by his magic crack repairs.

[screenman]

I do quite a few cracks and some maybe about 10% fail maybe due to stress or bad fitting or dirt or many other reasons.

But I still think, better to have tried and failed than never having tried at all.