Applying window tint film on the black dots of the car window
You've surely seen the black dots at the edges of the car's windows. Why are they there, and how do you get window tint film to adhere to them? It's not always easy…
The black dots at the edges of a car's windows can give any installer of window tint film gray hair. In actual fact, they fulfill a function that mainly stems from the design of the window and the appearance of the car, but unfortunately can cause some trouble when installing window tint film.
1. Why is there a black band around the car's windows?
The black frame around the edge of the glass is called the ‘frit’, and is an inlaid ceramic paint that is basically impossible to scrape away. The frit band along the edge of the glass serves three purposes.
1. It creates an etched surface that allows glue to bond to the window glass to the frame in the bodywork.
2. It hides the glue joint between the window glass and bodywork.
3. It protects the glue joint from drying due to the sun's radiation, thereby reducing the risk that the window glass loosens and the window starts to leak.
2. What are the black dots around the window’s frit?
The black dots are often referred to as matrix points or raster points. They are largest close to the frit band, and decrease in size the further they are from the band. The reduction in the size of the dots offers a more visually pleasing transition from the frit’s black border to the transparent glass, and also allows a little heat dissipation. The points also provide a certain level of shading from the sun.
3. What problems can occur when applying window tint film?
Irrespective of whether one uses adhesive-free removable window tint film such as EVOFILM®, or adhesive-window tint film, problems may occur due to the matrix points. For example, it can be difficult to get the edges of the film to attach to the matrix points, meaning to say that the film loosens at the edge and a white strip of air develops where the film does not adhere properly against the window between the dots.
4. How is window tint film attached to the black matrix points?
1. Select a high-quality window tint film. The cheaper the film, the more often there are problems. A soft, flexible, durable window tint film is considerably easier to get to look nice than a window tint film of the quality of aluminum foil.
2. Clean the car window glass scrupulously for successful results. Use T-red and a lint-free cloth when cleaning the car window. Take special care to clean all the way to the edge of the window. One tip is to clean the outside surface of the glass first, so that it is easier to see dirt and stains when you clean the pane from the inside surface of the glass.
3. Do not put too much solvent in the mounting fluid. This both causes stains on the window tint film when it dries, and also stops the film adhering to the window, so that it just slips. The standard dose is 2-3 drops of solvent in a 1-pint spray bottle, but if the problem persists, you can go down to one drop per pint of water.
4. All fluid between the window and the film must be removed. Use the edge of the scraper to be able to scrape properly between the matrix points. You can also use a soft cloth and your thumb nail to get around the points.
5. Allow the film to dry thoroughly before you judge the results and break down. Sometimes it works wonders if the film is allowed to dry in peace and quiet.
What can be done if nothing helps?
In the end, you can get desperate if nothing helps. Then you must resort to a little cheating. One thing you can do if you have trouble getting the film attached at the edges is to extend it by about a tenth of an inch so that, instead of ending exactly at the edges of the dots, it extends into the black frit band. It is usually easier to get the film to attach here because it is smooth. If you have problems with a white air border, you can do the opposite. Accept that there will be a white stripe, but finish it nicely anyway by cutting the film inside the black matrix points so that the strip will be even and neat around the entire window.
A common trick to get the film to adhere to the edge of the dots is to attach it with a few drops of clear nail polish or super glue. Ambitious people gently roughen the edge of the film with super-fine sandpaper first. If you have the problem with the white air strip, another (questionable) trick is to ‘paint’ black paint between the dots, but this requires that the film be removed and reapplied, or that you should buy a new film. Are things still not working? At this point, it’s probably best to live with it, or hand the work over to a pro.
