Film on Windshield

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Scoobygsx
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Film on Windshield

Post by Scoobygsx » October 31st, 2018, 9:13 am

Hello. I just bought my car about 4 months ago. There is a film on the windshield that only appears when there is condensation on it. It sometimes goes away momentarily when the wipers go over it, but quickly comes back. Ive tried Using windex, which didn’t make it any better.

Here is a video of it: https://drive.google.com/file/d/1cS3NBQ ... p=drivesdk

sunshine wr
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Re: Film on Windshield

Post by sunshine wr » November 1st, 2018, 3:57 am

A machine buff with a good glass compound (cerium oxide based) should remove it.
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Brent Deines (November 1st, 2018, 9:01 am)
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Brent Deines
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Re: Film on Windshield

Post by Brent Deines » November 1st, 2018, 8:58 am

I agree 100% with sunshine wr, a good machine buff with cerium oxide is probably the best and safest solution to your problem.

As for the cause of the problem, I think it is likely a coating on the windshield, which may have been deliberate, or may be just a spray wax or some other chemical that many automatic car washes use these days as their final step.

Wax, polish, or hydrophobic coatings like Rain-X or Aquapel leave a transparent film on the glass that helps repel water and contaminants. In some cases they also make the wipers work more efficiently but as they begin to break down the film becomes more visible, particularly just after using the wipers to remove water from the glass. The spots and streaks often occur on coated windshields when the vehicle is left outside in the rain and then allowed to air dry, and again, is much more apparent when you start using your wipers but may be nearly invisible when the windshield is wet or completely dry.
Sometimes simply applying a fresh application of a good hydrophobic coating will take care of the problem but that may only work if you know what was used previously and if the windshield is cleaned well before the coating is applied.

Depending on what was used on the windshield removing the coating may be as simple as using wax and adhesive remover, or pumice mixed with water to remove it. Hand applied Creme Cleanser is what I use and for tempered side and back glass I don't think anything works better but it is pretty aggressive so for softer glass like mirrors and windshields it can leave very fine scratches in the glass if you are not very careful. Actually I don't think it is the cleanser that leaves the scratches but as it dislodges the mineral deposits that are often the cause of water spotting and that my cause scratching. So for windshields and mirrors I agree 100% with sunshine wr, a good machine buff with cerium oxide is likely your best option.

I also recommend that you clean your wiper blades thoroughly with denatured alcohol or replace them at the same time you remove any coatings from your windshield. Wiper blades pick up trace amounts of the coating from your windshield with every pass and may continue to leave marks if they are not cleaned or replaced.

I have a love/hate relationship with hydrophobic coatings. I really hate them when I forget to test for them prior to starting a windshield repair and only realize it when my pit resin does not stick to the glass or when it starts to wear off and I experience the problem you are having. However, I love how well I can see in a hard rain at highway speeds without even turning on the wipers, I love how it reduces hard water spotting (especially on my mirrors and on my side and back glass with privacy tint), and I love how much easier it is to clean bugs off the windshield.

I apply Rain-X once a year to my mirrors, side, and back glass, but every 2-4 months on my windshield depending on weather conditions and find with that frequency I do not have to remove the previous application, I just have to make sure the glass is cleaned well. I also clean my wiper blades every time I apply a coating and replace them every year or two.

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Re: Film on Windshield

Post by Canadain87 » November 4th, 2018, 7:32 pm

Hi Brent,

had a question regarding testing for and removing windshield coatings before completing a repair. How and how? haha How do you test and what do you find is best for removing the coating before a repair?

Thanks

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Re: Film on Windshield

Post by Brent Deines » November 6th, 2018, 7:14 pm

I use an extremely sophisticated method that took many years to learn. I make sure the damage is covered and then spray a little water or glass cleaner on the glass to see how it beads up! I'm sure there must be better ways but once you know what to look for it's really that simple and if you are not sure take the next step...removal.

Removing the coating is almost as simple as identifying it, at least in small areas. Unless I'm 100% sure there is no moisture in the damage I use a moisture evaporator to remove any moisture trapped within, which also very effectively removes wax or hydrophobic coatings in about 20 seconds. Using the moisture evaporator has the added advantage of breaking down coating that may have seeped into the damage during the application of the product.

If I am 100% sure there is no moisture in the damage I use 0000 steel wool which also takes just a few seconds, then use my handy dandy Delta Kits dust blower to remove any fragments of the steel wool that might be left behind. I used to be very afraid of using steel wool because of all the damage I've seen others do with 000 or courser grades but I've been using 0000 for several years now and as long as the glass is clean there is never any scratching. One advantage of using steel wool is that if you forget to check for coatings and find your pit filler is not sticking to the glass you can still use steel wool to remove it.

If I do remove a coating from the glass surrounding the damage I like to put a coating back on. You don't always know they they used prevously but applying a bit of Rain-X will at the very least keep the repaired area shedding water like it did before you removed the prevous coating.
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Re: Film on Windshield

Post by Semper Fi » December 1st, 2018, 11:47 am

Brent Deines wrote:
November 6th, 2018, 7:14 pm
I use an extremely sophisticated method that took many years to learn. I make sure the damage is covered and then spray a little water or glass cleaner on the glass to see how it beads up! I'm sure there must be better ways but once you know what to look for it's really that simple and if you are not sure take the next step...removal.

Removing the coating is almost as simple as identifying it, at least in small areas. Unless I'm 100% sure there is no moisture in the damage I use a moisture evaporator to remove any moisture trapped within, which also very effectively removes wax or hydrophobic coatings in about 20 seconds. Using the moisture evaporator has the added advantage of breaking down coating that may have seeped into the damage during the application of the product.

If I am 100% sure there is no moisture in the damage I use 0000 steel wool which also takes just a few seconds, then use my handy dandy Delta Kits dust blower to remove any fragments of the steel wool that might be left behind. I used to be very afraid of using steel wool because of all the damage I've seen others do with 000 or courser grades but I've been using 0000 for several years now and as long as the glass is clean there is never any scratching. One advantage of using steel wool is that if you forget to check for coatings and find your pit filler is not sticking to the glass you can still use steel wool to remove it.

If I do remove a coating from the glass surrounding the damage I like to put a coating back on. You don't always know they they used prevously but applying a bit of Rain-X will at the very least keep the repaired area shedding water like it did before you removed the prevous coating.
Brent, I am not sure I can afford your sophisticated method of testing. :D
Semper Fi - USMC
Don’t give up! Don’t ever give up!
Jimmy V.

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