Applying a ceramic coating to the exterior surfaces of your car is the best way to protect it from the elements for years to come, but can every surface be coated? Even the windshield and side windows?
In this article I’ll explain how to ceramic coat glass properly, the preparation steps involved to get the best results and give you my recommendations of some of the best glass coatings I’ve tried.
Can You Ceramic Coat Glass?
A ceramic coating can be applied to the glass, including the windshield however the coating must be specifically designed for use on glass. Ceramic coatings designed for paintwork should not be used on glass as they may cause smearing and wiper judder.
Do not use a ceramic coating designed for paint, trim, plastic or any other substrate on your car’s windshield and other windows.
Some dedicated glass coatings do not use ceramic technology but are still considered equal to ceramic glass coatings in terms of performance and durability, hence I’ll be referring to them most just as “glass coatings” throughout the rest of this article.
Benefits of Coating Glass
Applying a coating to the glass offers a range of benefits including:
- Exceptional water repellency which allows rain to bead off the windshield when driving on high-speed roads, reducing the need to use the wiper blades.
- Prevents water and chemical stains so improves visibility when driving at night or in the rain.
- Making it easier to clean bugs, bird poop and other contaminants off the windshield.
- Reduces frost build-up in the colder months.
Personally I think a glass coating is one of the best detailing products to use on car. It massively improves visibility when driving in poor conditions and helps to reduce wiper blade wear so I make sure there is always a glass coating on my own car.
Best Coatings for Glass
Some glass coatings offer better performance (water repellency mainly) and durability than others.
One of the most common ways to measure the performance of a coating is to judge at what speed the beads start to roll off the windshield when driving in the rain. However, I don’t think this is the best metric to consider as it depends on how heavy the rain is, and the angle of the windshield on the car.
I have tried quite a number of different glass sealants and coatings now and have two stand-out favourites. Here are links to them both:
Both of these coatings are capable of lasting for 12 months on the windshield and can last years on the side windows as these are unaffected by the wiper blades. They’re both incredibly easy to apply and offer excellent performance so I don’t think you can go wrong with either.
Here’s the application instructions for each option.
Pyramid Carbon Glass Coating:
- Apply 6-8 drops of the coating to the provided applicator
- Evenly spread the coating across a section of the glass (e.g. half the windshield) in a cross-hatch pattern
- Wait for 15 seconds and buff off the residue with a low-pile microfiber towel
- Apply a second coat (repeat steps 1-3)
- Do not allow the glass to get wet for 4 hours after application
Soft99 Ultra Glaco:
- Use the built-in applicator to evenly spread the coating across a section of the glass (e.g. half a windshield) in a cross-hatch pattern
- Wait 5-10 minutes and buff off with a low-pile microfiber towel
- Do not allow the glass to get wet for 12 hours after application
How to Prepare the Glass for a Coating
Ensuring the windshield and windows are properly prepared for the glass coating is the best way to ensure it can properly bond to the glass and last for as long as possible.
The windshield in particular is prone to developing water spots and chemical stains which need to be removed prior to applying the coating. These stains are often responsible for poor visibility when driving in the rain, so you don’t want to essentially lock them in by applying a coating over the top.
Here’s what you’ll need to prepare the glass for the coating:
- Car shampoo (wax and gloss-enhancer free) and/or glass cleaner
- Clay bar
- Glass polish
- 3/4 x short-pile microfiber towels
If you are washing the rest of the car, you can use a wax-free and gloss-enhancer free shampoo to clean the glass. Avoid using shampoos which contain any residue or leave behind any protection.
The clay bar will help to remove any bonding contaminants from the glass to leave it feeling smooth. If you want more information regarding using a clay bar on glass, check out this article.
In terms of the glass polish, there are two options that I would recommend:
I’d highly recommend using a glass polish to prepare the substrate for the coating, especially if the car is several years old. It will help remove the chemical and water stains to ensure the coating offers the best performance and durability.
Here are instructions on how to use each of these glass polishes.
- Apply a small amount of the polish onto the provided applicator
- Work the polish in using cross-hatch or circular motions
- Buff away using a microfiber towel and glass cleaner to aid residue removal
Soft99 Glaco Compound:
- Gently squeeze the bottle to release some of the compound
- Use the built-in applicator to spread and work in the compound using medium pressure in cross-hatch or circular motions
- Rinse the compound away
- Dry the glass using a microfiber towel
I recommend using short-pile microfiber cloths to prepare the glass. Avoid using anything fluffy as this will usually leave fibers on the glass which can be difficult to remove.
My favourite microfiber towels for preparing for and applying glass coatings are The Rag Company FTW towels. These have the perfect design to effectively remove residue and avoid leaving fibres on the surface.
Here are the steps involved to prepare the glass properly for a coating:
- Clean the glass by either washing with car shampoo or using a glass cleaner and a microfiber towel
- Clay bar the glass using either the car shampoo or glass cleaner as a lubricant
- Drying the glass using a microfiber towel
- Polish the glass by working in circular motions
- Use a microfiber towel to remove the polish residue (or rinse and dry again if using the Glaco Compound)
- Clean the glass again using a glass cleaner or panel wipe solution to ensure the surface is completely clean
How to Apply a Coating to the Glass
Thankfully, once you’ve done the prep, the rest of the process should be very straightforward!
Make sure you always follow the manufacturers instructions regarding coating installation as they can vary between brands significantly.
Usually, the application process follows 3 simple steps: apply evenly, wait for the recommended time and buff away the residue using a low-pile microfiber towel. Coating all the glass on a standard-sized car should only take around 10-15 minutes to perform.
When applying a coating to the glass you should be mindful of the environmental conditions e.g. the temperature and humidity.
Ideally, coatings should be applied indoors but they can be applied outside as long as you use them in the correct conditions and make sure they do not get wet for the recommended period of time after application (see the next section for info on this).
Some manufacturer’s will state the recommended temperature and humidity conditions required to apply the coating. If this is the case, always follow these instructions.
However, if they don’t provide any info then I’d use the following guidelines:
- Apply the coating out of direct sunlight
- Ensure the ambient temperature is above 8°C/ 46 °F and below 25°C/ 77 °F
- Do not apply the coating in conditions where the ambient temperature will be outside the temperatures specified in the point above for at least 6 hours (but ideally 12 hours)
- Try to apply the coating when the humidity will be below 70% and will stay below 70% for at least 6 hours after application (but ideally 12 hours)
The only other thing that you need to be aware of with glass coatings is that there is usually a cure time involved. Ceramic coatings, once applied, need to harden (cure) in order to fully exhibit their characteristics and maximum durability potential.
Usually the brand will specify the cure times on the bottle or at least on their website. They will often state how long you must wait before exposing the glass to any water (even condensation).
Here are examples of popular glass coatings and the amount of time they must be kept dry for after application. All these coatings have a durability claim of up to 12 months on the windshield.
|Glass Coating||Keep Dry For|
|Pyramid Carbon Glass||4 hours|
|CarPro FlyBy Forte||4 hours|
|Carbon Collective Glass||12 hours|
|Gyeon Q2 Repel||12 hours|
|Gtechniq G1||12 hours|
|Soft99 Ultra Glaco||12 hours|
|NV Glass||24 hours|
Often the period of time you need to wait before the glass can be washed or any other chemicals used on it is not specified by the manufacturer. However, if you want to be as cautious as possible then wait 7 days before cleaning the car again.
Some brands also specific how long to wait until the wipers can be used, and others do not include this information. Ideally, you should wait 12-24 hours with most glass coatings before using the wipers.
Make sure you check the manufactures guidelines with regards to these cure times and plan accordingly when you should apply the coating.
How to Make a Glass Coating Last Longer
The main reason a glass coating will degrade more quickly than expected is due to the wiper blades. The friction caused by the blades rubbing against the coating can cause it to fail prematurely.
Luckily, glass coatings provide excellent water repellency so you may be able to use the wiper blades on a lower setting to reduce this abrasion. You should also ensure your wiper blades are clean and free from any grit/ debris, and are not worn.
If you really want to maximise the durability of your glass coating then you can use a water repellent glass cleaner to maintain it.
My favourite product for this is the Soft99 Glaco De Cleaner (Amazon link).
This product can be used after washing the car, or even between washes to clean the glass and add some protection to boost the performance of your existing glass coating. It’s incredibly easy to use and really does extend the life of the coating.
If you use a product like this every 2-3 weeks you can even surpass the durability claim of 12 months given on most glass coatings.
Glass Coatings vs Sealants
There are many different types of glass protection products on the market and they can usually be categorised into either: coatings or sealants. But what’s the difference?
Coatings are much more durable (usually lasting around 12 months) and offer a better level of protection and water behaviour.
Sealants usually only last a few months but typically don’t need any time to cure (unlike coatings as discussed in the previous section). Hence, they can be useful when dealing with unpredictable weather conditions.
Personally, I like to use glass coatings as the preparation remains the same either way if you want the best performance, and this is usually the most labour intensive step in the process.
To avoid having to polish the glass every few months, applying a coating will give you longer-term protection and it’s also not really any more complicated aside from the cure time considerations.
The price of sealants and coatings is also not dramatically different in a lot of cases and when you factor in the durability as well, coatings offer the best value for money.
How to Remove a Ceramic Coating on Glass
To remove a ceramic coating from the glass, it must be polished. Using abrasion is the only way to ensure the coating is fully removed as detergents typically are not as effective on glass coatings.
Examples of glass polishes:
- Soft99 Glaco Compound
- CarPro Ceriglass
- Tac Systems Glass Polish
- Gtechniq G4 NanoTech Glass Polish