Johnson Window Films Dealer Resource Center

JWF, Rear Windows - Dot Matrix Prep

Dot Matrix Preparation

When facing dot matrix patterns on a rear window, it's often difficult to apply window film because the dots themselves are relatively thick. This prevents the film adhesive from properly adhering to the glass. Covering the area with black vinyl is one way to combat the dot matrix problem. But if you still want to apply window film, here are a few quick tips to help ensure your film sticks to the glass:

Keep it wet if you sand them.  Don't scratch the glass.
Prepping with sandpaper
Sand The Dots (prior to sanding, mask glass with tape)
Using wet/dry sandpaper with a 220-240 grit (very fine black sandpaper), you can prep the surface of the dot matrix. Spray the area thoroughly with water and sand the dots with sandpaper (wrap the sandpaper around a small block of wood). Be sure to keep the area very wet so you don't scratch the glass surface of the window. Please note this technique requires a bit of muscle, but it will improve the film adhesion.

Limit chemicals to the dot matrix area.
Spray with Rapid Tac II
Rapid Tac II
Rapid Tac II is an adhesive activating solution that can increase the adhesion when applied to the dot matrix area. Just spray the dot matrix area with this solution and apply the film as normal. If you choose to use Rapid Tac II, make sure not to get the dot matrix area wet with your soap/water spray solution.

This is dangerous.  Be sure all of the car is covered and protected.
Using black enamel paint
Paint Over Dot Matrix
Another approach is to "fill in the dots" by painting over the dot matrix area. You can use flat black spray paint, or black enamel paint, to cover the area. We recommend applying paint at least a couple of hours before installing film to allow the paint to dry. Make sure you mask off surrounding window area to prevent the paint from accidentally dripping on anything unnecessary.

Glue Sticks
After installing film, pull the top of the film back to expose the dot matrix area. Take a glue stick (e.g. Elmer Glue Sticks) and apply on top of dot matrix area. The glue stick acts as an extra adhesive to help the film bond over the dots. Once you've covered the area, place film back and anchor the film with a squeegee. Be careful not to get glue stick adhesive on side panels and upholstery.

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