Milky Repairs

[Sunrise]

I repaired a BMW windshield yesterday. It seemed to have a milkey white area between the lamenent and the glass. Is there something diffrent about the BMW glass then other wndshields? Also, how does the new rain sensor windshields work, and can they be repaired?

[Chips-B-Gone]

Sunrise wrote: I repaired a BMW windshield yesterday. It seemed to have a milkey white area between the lamenent and the glass. Is there something diffrent about the BMW glass then other wndshields? Also, how does the new rain sensor windshields work, and can they be repaired?


That milky white area may be water or moisture that was trapped in the break. I had this happen in a class 8 commercial truck (Freightliner) a couple of years ago.

[Glassdoc]

Most 5 series and bigger beamers have factory tinted glass. Sometimes the shot will come out perfect (seldom on these), sometimes it can have a silver hue to it, sometimes it may have a white-ish look to it.. its all to do with the factory tint. I've tried thinner resins, colored resins, thicker resins, curing longer everything known to man.. If the tint is separated between the glass and laminate it will have some sort of visible defect. The older Grand Marquis, and the Olds Shilloettes, had this same type tint in them.. No way around it, just pray it comes out 100% but address the issue with the customer before doing the repair so they are aware..

[Brent Deines]

Glassdoc,

This is very interesting to me. I have repaired all the vehicles you mentioned, and never had this problem. In fact, other than water in the break which has already been mentioned, I never heard of this problem until a few weeks ago. I have done my share of repairs on BMW vehicles, although I must confess I have not done a repair on a new 5 series.

We have some pretty good contacts at BMW. I'll see if they can shed any light on this issue.

[screenman]

We are more likely to see this after effect on solar contral screens that are fitted to Renualts, Peugeots and Citroens over here. They tend to have a very distinctive sort of purple appearence to them, you can see the silver effect before you start the repair.

[sgailey]

Did it look anything like this?



Last summer I encountered a blemish similar to what you're describing on one particular fleet of vehicles. The general consensus seemed to agree it was either contamination or delamination, or a combination of both.

Do you know how old the break was?

[StarQuest]

I've experienced milky repairs before (cloudiness in lamination) but to be honest all were very old damage. I haven't seen that with new damage on any vehicle to date.

I have experienced silver outlines on solar reflective shield repairs, mainly (Chevy Ventures and Pontiac Montana's). You can identify these shields pretty easy, just look to see if they have a purple reflective tint to them. If they do, it's best that you explain to customer before repairing that you can guarantee it from further spreading but the cosmetic damage caused by the stone hit is permanent and can be improved but not fixed.

This may be a little off topic but I just recently noticed a flowered shadow in lamination on a couple newer BMW vehicles after drying out damage with heat and it didn't go away. Wasn't noticeable at all from inside of vehicle but if you closely inspected it up close from outside, you could see it. Used the same heating techniques as I've been using for all other dry outs but was thinking maybe these shields can't be dried in the same manor.

[Glassdoc]

BMW is big on pushing Aquapel (windshield treatment similar to RainX) across the parts counter..

[Brent Deines]

Matt talked with someone at BMW today to see if they had experienced any of these problems doing their own repairs. He was told that some of the dealerships are applying a coating to the outside of the glass which has caused the resin not to stick to the surface, but once identified, the coating is easily removed from the surface of the glass using cerium oxide. Still waiting for more feedback, but so far they have not reported the milky repairs that others have mentioned.

The next time someone experiences this problem, get as much information as you can about the car so we can pinpoint the type of windshield being used. Maybe we can get the same windshield in here for testing and ask the manufacturer some specific questions about how the windshield is constructed.

Years ago I spoke with someone at PPG that told me air sometimes caused these types of windshields to discolor, sometimes causing a whitish or silverish appearance. I think he may even have written an article about it, but I can't seem to put my hands on it at the moment. Can any of you that are experiencing this problem tell me if the damaged area was discolored before the repair was performed?

The photo from sgailey looks like an old break to me, but I have also seen car wash soaps and/or waxes that cause a break to look like this. I suppose it is possible that some of the coatings that manufacturers use on the outside of the glass could also cause this effect. Rain-x contains denatured alcohol which softens the laminate and contaminates the resin, either of which may cause discoloration. It is quite possible that some of the other coatings use contain similar products that may damage the laminate.

That brings up another point. As has been discussed many times on this forum, much to my dismay many technicians actually use alcohol to dry out a break. Are any of you that are experiencing problems using alcohol or any other product to dry out breaks or remove windshield coatings?

The reason I ask is because I never inject anything into the break for any reason, and again, in 20+ years of repairing windshields have never experienced this problem.

[Bois]

Are any of you that are experiencing problems using alcohol or any other product to dry out breaks or remove windshield coatings?

I don't use alcohol to dry out a break but I do use it to remove Rain-X coatings - sometimes in advance of repairing a break if I'm aware of the treatment. I use a Q-tip to clean the break area and I'm sure that some alcohol gets into the break. So far I can't say that this has caused a problem but I will keep an eye on it.

What usually happens, though, is I repair the break and find out afterwards that there is some type treatment because the pit resin doesn't adhere to the glass (breaks off when using razor blade). I then use alcohol to clean the area and re-aply the pit resin. Of course, the break itself is cured so no alcohol gets in. Maybe this is the better method - removing the Rain-X after the break is cured.