The Window Tint Dot Matrix Dilemma

Dot Matrix Dilemma

Anyone that has installed window film on a car is familiar with the dilemma of how to get the dot matrix areas to look good and consistent. Installers have tried everything from sanding the matrix to using glue sticks to combat the issue. Some have given up completely and just install solid black vinyl over the matrix area and but seam the window film to the vinyl.

Why is this issue so difficult to overcome? Well, with the exception of installing vinyl, one strategy will not work for all situations. In an effort to add some clarity to this issue, I wanted to detail out the various issues with dot matrix and the primary ways that installers are currently addressing the dot matrix dilemma.

To begin with, there are two main issues that installers deal with regarding dot matrix during a window film installation. The first is getting window film to stick properly in the matrix area. Often the film will want to peel back and not want to stick in this area. After discussing this with people in the glass industry, this issue stems from the fact that many of the materials that matrix is comprised of are designed to be resistant to things adhering to them. As a result, we are fighting the natural tendency of the material by trying to adhere something to it. As an illustration, think of trying to get things to stick to the inside of a Teflon coated pan. try as you might, things just do not want to adhere.

The second issue is that the installer can get the film to adhere to the dots, but the film appears to have a “silvering” in the matrix area when viewed from the outside. (See Picture) To make matters worse, this “silvering is often not uniform or consistent across the window drawing even more attention to this problem.

So, what can we do to combat these issues. Let’s tackle the first issue of the film not wanting to adhere to the matrix. The most common strategy for this is to use something to scuff the surface of the matrix area knocking off the top coat and creating a rougher surface that the film has an easier time adhering to. This method is often used in combination with a adhesive promoting solution. The idea is to make the material more conducive to the film adhering and then giving the adhesive the added boost of an adhesion promoter. This tends to work well at getting the film to stick to the glass, but the issue of “silvering” might still be present.

What causes the silvering? The basic explanation is that the profile of the dots serve to keep the film floating above the actual surface of the glass. The dots are spaced too closely together and the film rides on the top of the dots unable to deflect into the valleys between the dots to stick to the actual glass. The resulting gap between the glass and the film in these areas is what you are seeing when “silvering” is present. You may notice that as the film cures that you can push down in these areas and reduce or eliminate the silvering. This is because once the mounting solution is completely dried out you can often push the film into these valleys and get it to stick to the glass. Often, even you are successful getting this to occur, the “silvering” will return to these areas again as the film cannot maintain adhesion in these valleys. again, the use of adhesive promoters in these areas might help this, but getting uniform adhesion across the entire matrix is difficult.

The only way to truly take care of silvering is to fill in the gaps left when the film rides on the top of the dots. This is often done through the use of a clear glue stick. The idea is to fold back the film to just below the matrix and run a bead of glue at the juncture of the film to glass. Then lay the film back down and squeegee the glue line evenly through the matrix. The excess glue will flood the valleys between the dots and eliminate the “silvering” as that gap is now filled with glue.

The last option is to trim the window film  just below the matrix and apply a black vinyl in the area that the matrix exists. This can be done very neatly via a butt seam method and give goo visual results from the exterior. However, it does change the look of the window from the inside and some customers might want that.

I hope this explanation helps some of you deal with this pesky issue. As always, your experience might vary from this and these are just suggestions. Please try these and other methods at your own discretion and take precautions to not do any damage to the vehicle you are working on.

14 Comments Comment

  • tom borst on August 12, 2014

    U have 2 change the customer an extra 50$, ² sand down a dot matrix on a back window, using a 1,000 grit sand paper, and must ape up bottom line, u may have 2 make a few passes,
    The matrix is a 3 mill raised dot, and need 2 sand down 2 1 mill, u can real the difference, and with out scratching the glass, its all prep, and lots of elbow grease,
    What I love 2 do is have the customer come back 4 final inspection and show the customer, how pressing the film into glass after it has cured, and looks even better, just fin lines around the dot, and the customer is even happier the u took the extra time 2 I inspect the job and 2 give the dot matrix a little TLC, and is great 4 customer referrals

  • saul on August 12, 2014

    Glue on dot matrix wuld be nice if glue din’t turn yelow with sun expousure. in my opinion vinyl is the best option

  • Tintmaster68 on August 12, 2014

    Clear elmers glue is about the best way to get the matrix to lay down. Just prep for it and be prepared for the excess glue coming out as not to get it on there interior. This I have found to be the best fit for customers( no explaining about dots) and there friends see a really clean job and call you too. 29 yrs. exp. been using elmers for ten eleven years now with no reoccurring issues

  • A2 Customs on August 12, 2014

    we use black one shot sign paint with a sponge brush then matte black vinyl over that comes out perfect every time. No more silvering

  • Jan Daniels on August 12, 2014

    Nice article! I made actually video installing film with the use of vegetable based glue. I can upload it for you if you are interested. This special glue is free to all our clients in Europe!

  • Steve Bankard on August 13, 2014

    The variation of the dottied matrix is the key to the problem. I have used the ‘blue’ Elmers glue for years with no problems. ‘clear’ Elmers is ok but doesn’t seem to work as well. I suggest a clear explanation before the actual installation is always best. Its usually the guy with the cheap car that always complains the most. Sometimes leaving the film hanging over the dot matrix until dry and then evely pushing it into place works as well. 34 yrs exp.

  • Frank on August 17, 2014

    One option is to not apply film to large matrix rear windshield areas at all. Instead, you can paint it in black with customers approval which would be an up-sell opportunity worth an extra $20.- $30.
    A good quality black spray paint in a matt or semigloss finish properly applied in 2-3 light coats should do the trick. Take extreme care to mask and protect other areas. Usually best done “after” the film is applied and has a chance to tack and dry.

  • mike on August 19, 2014

    Maybe 3m could design a dark film with an adhesive that would fill the matrix valleys in a 10 inch size for this application.

  • Patrick LeonGuerrero on August 22, 2014

    sir we prep the dot matrix with 5oo grit sandpaper then squeegee clean the area then follow last step with bounty paper towel with laquer thinner then wait at least 5min then install window film I have been doing this method for at least 10yrs and no problems off peeling or bubbling thank you Pats window tinting Guam…

  • edward soja on August 28, 2014

    If you want to do it right get some wire wheel acid and a steel wool pad to attack the faux ceramics first, then use a 500 grit s/paper with some lemon juice to prep it or you can use vodka too if you like , then let dry 5 min. now when you apply use baby shampoo from the dots down only wet the dots with plain water, use a evacuator on the dots with much pressure. “POOF” a perfect window every time. be sure to cover the seats and deck too!

  • Llumarman on October 14, 2014

    Use a grinder and cut out that part of the glass, viola no dot matrix to deal with!

  • Patric Fransko on October 16, 2014

    Lol…That’s one way to handle it. 🙂

  • Don Decoteau on July 28, 2016

    Everyone loves what you guys tend to be up too. Such clever work and exposure!

  • Interwest Tools on July 29, 2016

    Thanks for the good feedback 🙂

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