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Star break question?
Posted: February 7th, 2009, 6:23 am
by DRyder
I recently drilled and filled a star break, being careful to slowly introduce the resin beyond the vacuum state. As I slowly began to fill it one leg extended out around another 1-1.5 inches, but did fill. My question is do you think I should have drilled beyond the crack and back filled to prevent it from running further or being that it filled the first time, will it be ok? Thank you for your input from a newbie.
Re: Star break question?
Posted: February 7th, 2009, 9:22 am
by Chips be-gone
With the crack out being that short I would not think drilling would be necessary as long as you filled the crack completly. Flexing a little to make sure it is filled.
Re: Star break question?
Posted: February 7th, 2009, 10:52 am
by Windshield Doc
I think what DRyder is asking is how to prevent from the leg getting longer as you inject the resin. Actually, I've seen a crack do this, the more resin you put in it the more it cracks out. I think the reason for this is because the deference in the temp of the resin and the glass
Re: Star break question?
Posted: February 7th, 2009, 11:38 am
by screenman
I would say it very unlikely to be anything to do with resin temperature, we use such a small amount compared with the volume of glass that almost as soon as it touches the glass it is about the same temperature, certainly by the time it has flowe down to the end of a 1 inch crack which is only microns wide it would be at the ambient temperature.
I would say far more likely to be incorrect setup of the injection and or bridge equipment, or maybe even excessive temperature of the glass you are working on.
When checking temperature without equipment try using the part of your hand under your thumb on the palm side, if it is too hot too comfortably keep this part on tye shield it is too hot work on.
Re: Star break question?
Posted: February 7th, 2009, 12:48 pm
by Brent Deines
It may also be that the crack was already there, but had partially "healed". By that I mean that often a crack will appear to shorten in length if left unattended, but as the resin flows into the crack it opens back up to it's original side. This often happens with fresh cracks that are still clean and tight. We see it a lot in training when we make a crack in the morning it appears to be several inches shorter by the afternoon.
I'm not disagreeing with the other responses, just adding another possibility to consider. I look at the break from every direction possible and use an inspection light to be sure I am finding the true end of the crack. I also like to flex slightly from the impact point a couple of times to see if I see movement beyond what appears to be the end of the cracks.
Re: Star break question?
Posted: February 8th, 2009, 10:53 am
by jayjacque
I agreee with the hidden part. Some of these are hidden cracks, just begging to split out if not extra careful. Another thing that surprises me once in awhile is how you can concentrate on trying to keep the crack from extending one way, then all of a sudden it wants to crack out in the opposite direction on the opposite side of the pit. Thank God it's not often, but it does happen
Re: Star break question?
Posted: February 8th, 2009, 11:31 am
by screenman
I have been giving some though to this and the last time I had a starbreak run a bit on me was about 5 years ago, I know for sure in that case it was a rare occasion for over here when the screen was too hot. Not saying that is the case with this one.
Re: Star break question?
Posted: February 9th, 2009, 6:12 am
by DRyder
Thank you all for your input, any help is always appreciated.
