Whether you’re wrapping an HHR or installing vinyl graphics on a new police cruiser, proper surface preparation is a key to customer satisfaction. Any substrate must be clean and dry before applying vinyl graphics. With vehicles, there are unique surface preparation factors that must be taken into account. Some of these factors are dirt, waxes, paint, and polycarbonates.
Dust and Dirt
Getting the grime off is elementary, but sometimes dust can cause more problems than you’d think. Trapped dust is one of the most common causes of bubbles in applied vinyl. Make sure your surface is clean, dry, and free of lint and dust before applying your stickers.
For removal of grease, oil, wax, and so on, Avery’s surface preparation guideline recommends scrubbing with a solvent wipe (Xylene, heptane, ethylacetate or denatured alcohol) with the following caution: “After proper cleaning, the substrate surface should be thoroughly wiped using a clean rag saturated with a cleaner such as DuPont’s Prep-Sol Brand Solvent 3919S, Rapid Prep by Rapid Tack or Sherwin Williams R7K-156. NOTE: Other solvents such as IPA (isopropyl alcohol), VM&P Naptha, Xylol or lacquer thinner may also be used instead of DuPont 3919S. However, care should be taken to assure that the final dry wiping is accomplished prior to the solvent evaporating.”
Silicone Waxes and Surface Coatings
Some auto dealers add silicone-based coatings to new vehicles during dealer prep. Silicone can migrate into the vinyl’s adhesive and cause it to fail.
When applying graphics to a newly-delivered vehicle, Oracal recommends: “…contact your local dealer for the best way to remove (any silicone based) coating. Usually a wash with a commercial cleaner and an isopropyl alcohol wipe down will do the job.”
A slightly less obvious problem is uncured paint. Many automotive grade paints take time to completely outgas. As the paint solvents outgas, they deteriorate the vinyl’s adhesive bond and lead to failure of the graphic. On the other hand, vinyl can be applied to baked enamel paints as soon as they’re dry. If the car has been painted by a local body shop, make sure you know what kind of paint process they use.
Polycarbonates and Bubbles
A similar problem comes from applying vinyl to a new polycarbonate fixture, such as a headlight or taillight cover. New polycarbonate fittings need time to outgas. If vinyl is installed too quickly, bubbles will emerge under the film. This can be a baffling problem because the graphic looks perfect when installed. At the very least, a new Lexan® or other polycarbonate surface should be cleaned with ISA before applying vinyl. But that may not be sufficient.
Oracal recommends: “Polycarbonate should be baked 4-24 hours at 250° in an air-circulating oven before applying pressure sensitive vinyls. In some applications, flaming can be used.”
Avery suggests testing a small sample of Avery vinyl on the polycarbonate and baking it for 18 to 24 hours at 149° to 158°F. If outgassing occurs during this test, application with Avery vinyl is not recommended.
The wisest course is to follow the recommendations based on the brand of vinyl you use. So stock up on alcohol wipes and remember the five P’s: Proper Preparation Prevents Poor Performance!