Well, I had my first repair...uh...not...repair. I did everything I was suppose to (at least I thought I did). When I was done with the repair I didn't notice any air or anything. From what I could tell it was a well done job on a bullseye. Well, a few hours later I get a call from the guy saying that the black spot showed back up and now there was a crack about a half inch long coming off of the bottom of it. I've never had this happen before. Any idea as to why this might have happened? It was cold outside when I did the repair and the resin was a little warmer than the windshield but not by much. I've just been scratching my head trying to figure out what happened.
Maybe some of you can help me out. What would cause this thing to basically refill with air AFTER I've sealed it up and cured it and form a small crack? It looked fine when I left but it's all screwed up now. So what would cause this and how do I fix it?
broken.jpg (4.87 KiB) Viewed 740 times
It basically looks like that illustration. The dark spot is obviously where the air is and that is about where the crack is coming off of it. I was thinking I could just pick a spot and drill into the dark area of the break and try to fill it, hopefully it will get into the crack and fill it as well. But I don't know. Maybe you guys can help me out on this.
Did you dry it out with a moisture evaporator before the repair? Did you see the crack coming off the bullseye before you made the repair? A call to Delta might be the best thing to do first thing in the morning.
It didn't have any moisture in it because he got it the day after the rain stopped here. I checked it for moisture and didn't see any signs of it. So I don't know. The only thing I can think of was that the resin was warmer than the windshield and that might have done it. This is my first winter to do repairs. I'm starting to see that with the cold brings the need for extra equipment I might never have thought of.
hmmmm... not sure what to tell you. I would call the Delta guys in the morning and they will be able to troubleshoot the process you went through doing the repair faster and better than we can here.
I agree that moisture may have been one possible culprit, but it also could have been that traces of a hydrophobic coating were in the break. If you didn't use your preferred method for removing the coating (if present) suggested by your manufacturer, it may have prevented the curing in the area; allowing the break to show up again since the resin would not have bonded to the coating. This can happen easily to bullseye breaks if the car has been run through an automatic car wash since many carwash products contain a hydrophobic coating of some sort.
Just another possibility, it's not always the case, but if it wasn't moisture, the hydrophobic coating would be my next logical conclusion, preventing the resin from bonding to that part of the break, as you mentioned that before curing the resin had completely filled the break.
Why not. Just drill in that black spot, to open the void, follow the standard procedure, including DRY OUT, fill and cure properly, done. This should normaly work, good luck.
Slightly warmer resin would not cause that. I think you have the right idea about drilling into the air space. As a precautionary measure you may want to also dry it out after you drill just to make sure that if moisture was the problem, "all" of it is gone this time before you inject the resin.
It is odd that the break showed the black air space before the repair, did not after the repair was complete, and then showed the air space again at a later time. If you properly fill a large void with resin and properly cure it there is no way for air to re-enter or move around in the break. If it was so full of water that the resin could not enter you should not have been able to see the air space before starting the repair, and if there were only small amount of moisture in the break might see some air spots, but you should not see that much air space when it dried out. Just as with water, hydrophobic coatings won't change the appearance of a properly filled bullseye, and of course you would know it was present when you cured the break and your pit filler did not stick. You did not mention your pit resin not sticking so I am assuming that is not the case.
What this really sounds like to me is an overheating issue as when the glass expands it can make the break look full, but then when it cools it can open back up again. Been there done that! However you mentioned the glass was cooler than the resin, so I assume the glass was not overheated.
One other possible cause is if the injector is screwed down too tightly against the glass, partially closing the break. What can happen if you do this is that some resin will enter the break, filling the "available" air space. In this case the break will look full of resin, and technically that is the case, but when the injector is removed and the pressure therefore relieved from the glass, the break can open back up. In this case you would typically see the air space before the cure, or when you finish scraping off the cured resin. However, in some cases there is just enough resin in the break to create a bond with holds for a brief period of time before it opens back up. I have seen this most often when technicians cure under pressure, but I have also seen it happen on rare occasions even when the break is cured after the injector is removed.
This is all speculation based on assumptions at this point since you are the only one who knows exactly what the break looked like prior to the repair and exactly what steps you took during the repair process, but hopefully knowing all of the possible causes will reduce the chance of you experiencing this problem again in the future.
Thanks for the replies guys. I've got to drive back out to the guys house tomorrow to see what I can do for him. I'm hoping that the little crack coming off of the break hasn't turned into a large crack all the way down his windshield. I figure I'll just drill into the void, do some dry out just to be safe and refill the break. I hope I get it this time and I don't lose the windshield. I hate losing windshields, as I'm sure we all do. Not because I feel like I failed but because I don't want to listen to the...um...upset customer who isn't happy that I failed. I always learn something from a crack out but all poor Mr. Customer learns is that he gets to pony up for a new windshield because I screwed up.
