cloudy "crescent moon" shape after bulls eye repair

[David T]

Greetings all,

I recently did WS repair that had a "bulls eye" (smaller than a dime). After one pressure/vacuum cycle, I was impressed that there was no damage that could be seen from the inside or outside of the WS.

Did a 2nd complete cycle, removed bridge (repair looked flawless), applied pit resin, cured and applied pit polish. Then checked the repair from the inside of the vehicle and noticed a "crescent moon shape" cloudy image in a portion of the space of where the bulls eye was.

While the customer was happy with the repair, I felt it could have looked better. I called DK for advice (thanks Korey) and was informed that this was the result of either too high of a temperature (I didn't apply any heat at all and the outside temp. was in the high 80's) or too much pressure on the injector (I don't recall using more than 3/4 of a turn on the injector after the seal made 1st contact with the WS).

Has anyone else experienced this? After doing a search on the forum, I wasn't able to find any mention of this phenomenon (which is why I started this thread), but I'm sure it must have happened to other WSR techs at some time.
If this is the result of too much pressure, can anybody explain why this would create a "cloudy" appearance in a portion of a bulls eye after filling and curing?
Any feedback would be appreciated.

Thanks,
David T

[t4k]

Was it moisture?

[GLASSTIME]

I want to make sure I understood you correctly DavidT in your starter post.

You stated you did the first Pressure & Vac Cycle, Then you performed a second "Cycle" meaning you only did 2 pressures and 2 vacs?

[Kgobin]

David Per our phone conversation yesterday, you indicated that the vehicle was an older model Ford and the ambient temperature was in the high 80’s but did not know the glass temperature which could have been much higher. With the possible high temperature, an older vehicle, and too much pressure on the injector could lead to delamination. Those are the three main causes of delamintation which could be what you are referring to as “cloudy”. However, without seeing the repair it is difficult to diagnose the issue. If possible please send in a picture so we can have a better chance analyzing the issue.

[David T]

Thanks for the responses.

Moisture in the damaged area? Since I used a Delta moisture evaporator for 20 seconds prior to the repair, I don't think this was the cause.

Vehicle age? I don't think it was more than 10 years old. I'll check with the customer and post the info here when I find out.

Heat/temperature? While the temp was in the high 80's, the vehicle was parked in the shade and the WS did not feel warm to the touch.

Pressure/vacuum cycles? I did 2 full cycles; 5 minute pressure and 30-45 second vacuum. After these cycles, the damaged area looked nearly flawless (from inside and out), in fact after removing the bridge assembly and putting it back in the toolbox, the damaged area was actually a little bit of a challenge to find again.

I had asked the customer if Rain-X had been applied to the WS. She claimed it had been used about 4 years earlier. Since the "image" didn't appear until after the curing process, might this be the cause?

Too much pressure on the injector? Possible. I did screw the injector 3/4 of a turn after it first came in contact with the glass surface (but was advised that 1/2 turn is the recommended amount). Would just an extra 1/4 of a turn on the injector make that much of a difference in the amount of pressure? Can someone explain why excessive pressure would cause this type of "image" to materialize in a damaged area?

I'll try to get a photo of the "crescent shaped" image and post it here. Perhaps with the help of the Delta staff and techs that are more experienced than myself, this thread may make it possible for others to avoid this type of experience.

Thanks once again,
David T

[bullseyeben]

I have never seen this. I do nearly all my repairs in direct sunlight with temperatures exceedingg 100 degrees nearly everyday. I have had my delta kit since 2000. I have learned that I do turn my injector way too much if 1/2 turn is what is recommended. I probably turn it 3 or 4 full turns after it touches the glass and still have never had a problem.

[Brent Deines]

If you used the moisture evaporator correctly I don't think moisture in the break was the problem. How long did you allow the glass to cool after using the moisture evaporator?

A 10 year old windshield is certainly old enough for delamination, so if the break was also old moisture and contamination can cause a cloudy look. However, you stated the crescent shape appeared after the repair was complete so that does not sound like the case. Did you notice the cloudiness before or after curing?

You said 2 full pressure and vacuum cycles, which would mean you ended in the vacuum cycle. If that is the case that could be part of the problem. You should always end in the pressure cycle. I recommend a "minimum" of 3 pressure cycles and 2 vacuum cycles. Only the first pressure cycle needs to be 5 minutes. Additional vacuum cycles should be at least two minutes. Always end in the pressure cycle. Not cycling enough and ending in the vacuum cycle can cause air that is trapped at the outside edge of the break to migrate toward the center of the break. This can happen slowly so you might not notice until after you remove the light.

A 1/4 turn extra could be too much in some cases, but not usually. 1/2 turn is usually enough, but what you want you are trying to accomplish is a level bridge with as little pressure on the break as possible. How could this cause the problem you ask? If you have too much pressure on the glass the break will close up a bit, so when the pressure is released the break opens back up sucking air in from the surface. If you get the pit resin and curing tab on right away it may not pull air from the surface, but there is still extra space in the break so as the resin shifts air spaces are created. This can happen slowly so you may not notice it until you remove the light. By the way, over heating can produce the same results.

When Korey spoke to you he did not understand you to say the crescent shape was cloudy, so he assumed you were talking about air space, which would most likely have been caused by one or more of the things he mentioned. A four year old Rain-x application would not cause this problem and if your pit resin stuck to the glass there was no hydrophobic coating issue. You should however never trust what the customer says. They sometimes forget, or in some cases may not even know that a hydrophobic coating was applied to their windshield. It's fine to ask, but always check yourself to be sure. I would not rule out some other form of contamination though. A few car wash soaps/additives have been know to leave a residue in the break that reacts to the resin and does some strange things.

It is impossible to give a 100% accurate diagnosis over the telephone or on the forum, so we are just throwing out educated guesses based on our own experience. My best guess based on your cloudy description is contamination in the break, but without seeing a before and after shot it's tough to say for sure. In fact even photos don't always guarantee we can accurately identify the problem.

If it was air in the break you should have been able to drill and fill to remove the crescent shape, but if it was contamination there was likely little you could do to make it look better. Luckily contamination does not generally lead to structural failure, but it minimizes the cosmetic improvement. I always warn customers with pre 1990 cars that the older windshields do present special challenges cosmetically just in case you do run into a delamination problem. Be sure to check the edge of the glass for signs of PVB degradation. If you see signs of delamination at the edge warn the customer and proceed with caution.

[t4k]

Thanks for the responses.

Moisture in the damaged area? Since I used a Delta moisture evaporator for 20 seconds prior to the repair, I don't think this was the cause.

David T

The only reason I mentioned moisture was because in your original post you said: (I didn't apply any heat at all and the outside temp. was in the high 80's).

T4K

[screenman]

Quite often I hear guys say I used the drystar so it cannot be water, we MUST learn to recognise moisture and not just depend on the tools to know when it is dry.

This cloudy area, was it like a slightly grey,opaque colur? was it possible it was in the PVB before you started the repair? a lot of guys do not notice minor delamination prior to starting the repair, unless viewed from inside the car it is sometimes hard too see.

[David T]

Brent,

I think your words were right on target. I removed the bridge with the injector still in the vacuum cycle. Much like putting a drinking straw in a glass of water, placing your finger over the top of the straw and removing it from the glass, the straw will be filled with water.

I believe that removing the bridge with the injector still in the vacuum cycle "sucked" some of the resin out of the bulls eye and allowed air back into the damaged area (causing the "crescent" shaped image in the WS).

After considering the other possibilities, this sound sounds like the most likely cause of the image left in the bulls eye. What do you think guys?

David T