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Vehicle wraps are nothing new. We’ve learned how to avoid bubbles and even how to approach corrugation. But don’t get too high and mighty. Wraps are getting more complex and customer expectations are increasing. What was acceptable five years ago with retail customers (a few wrinkles and a slight misalignment of the graphics) won’t fly today with corporate customers ­ not if you want the high-paying jobs.

If you want to wrap with the big dogs, you need to learn how to handle the complex contours of automobiles, vans and buses. It all begins with the proper film selection and surface preparation, and it continues with unique film application techniques suited for complex contours. While you’re at it, you may as well learn how to remove those vinyl graphics from your challenging contours, too.

In part one of this two-part series, we’ll look at film selection and surface preparation with a special focus on the needs of complex wraps.

Selecting the Right Film
Covering complex curves and contours requires special techniques, including heating and stretching the film. The specific characteristics of a film, as well as the complexity of the vehicle shape, determine how well the film will hold to the curved substrate, according to 3M Technical Service Specialist Michael F. Stavreff.

“Vinyl film has a memory for its original shape,” he explains. “Stretching the film can result in some shrinkage as it attempts to return to its original dimensions. As it shrinks, you can expect some lifting and tenting of the graphic in stretched areas.”

Stavreff’s best advice: carefully read your product bulletin for the film you are considering. As you do, look for specs that will help you determine the film’s suitability for contours and complex curved surfaces. Generally speaking, you may be able to get away with 4-mil films on flat areas and vehicles. But you’ll need to stick with 2-mil cast films for applications that involve complex surfaces. One of the key differences between calendered films and cast films is that cast films are manufactured with very little inherent stress in the materials. That translates as much less shrinkage.

Common Film Selection Mistakes
“One film selection mistake that’s often made is to assume that a film with a more aggressive adhesive will overcome the ‘memory’ tendencies of calendered films,” Stavreff explains. “Taking this approach can lead to a variety of problems including the likelihood that the graphic will pre-adhere during installation. The use of overly aggressive adhesives also can lead to difficulties in removal with possible damage to the vehicle’s paint.”

On the other end of the spectrum are low-tack “changeable” products. These products may not require a professional installer to perform the graphic removal on the back end. But if you decide to use these low-tack products, then proceed with caution: it becomes even more critical that you use a 2-mil cast film. Otherwise, you may wind up with excessive shrinkage. The graphic could even lift from the surface of the vehicle. In that case, all of your hard work goes down the drain and you have a very unhappy customer.

Printing can also affect the properties of a graphic. If solvent inks are not dried well, the vinyl and the adhesive will absorb the solvent, causing two problems, according to Stavreff. Although the adhesive may feel “stickier,” solvent in the adhesive will ultimately cause a drop in adhesion. What’s more, while solvent in the film makes the graphic softer and easier to form around the vehicle, Stavreff said the solvent will eventually evaporate out of the film, and the graphic may shrink. Again, that’s not good if you want repeat business.

“Another consideration, of course, is the use of application features built into the adhesive. The ability to reposition graphics during installation has become more important as the scale and complexity of wraps has increased,” Stavreff notes. “If you are unable to position and then reposition the graphic as necessary prior to full adhesion, there’s a greater chance of ruining the graphic and having to reprint it. In addition, some films provide air release channels in the adhesive that eliminate application bubbles and can help reduce installation costs.”

The Importance of Surface Preparation
Before you tackle that complex wrap, you need to get back to basics. If you ask any vinyl manufacturer or application expert what is the most common mistake people make in the vinyl installation process, then you will get the same answer every time: inadequate preparation of the substrate’s surface.

“The biggest mistake is not prepping the surface,” says Jeff Stadelman, technical marketing manager for MACtac, a manufacturer of pressure sensitive adhesive products. “It’s so important to have a clean surface to put the adhesives down on. That’s definitely the number one error.”

From dirt to grease to mud to various other contaminants, vehicles tend to need at least one thorough cleaning before tackling any kind of wrap. That becomes even more critical when grease and grime is trapped in complex contours and curves that need to be covered with vinyl. If you don’t prepare your surface, simply put, your vinyl probably won’t stick, or at least it won’t stay stuck for long.

“People often want to skip the most basic step,” says Nathan Franzblau, founder of the Professional Decal Application Association, an association of independent certified vinyl installation companies. “If it is a trailer, then some people don’t want to take the time to clean it. If it is raining, then some people don’t want to take the time to dry off the raindrops. But that is a mistake. The materials are designed to work, but they are designed to work under the correct specifications.”

How to Prepare the Surface
The first step is washing the vehicle with detergent and water. Next, thoroughly rinse and dry it. Don’t forget to clean those hidden areas where graphics may be applied. And keep in mind that panel seams and body moldings can retain water, so you need to let the vehicle dry for 24 hours, or at least overnight, in an indoor environment. If you are hard pressed for time, you could choose to use a hot air gun to dry the vehicle more quickly.

Domestic paper towels are often the best means of wiping down the surface because even clean shop rags can accumulate contaminates like wetting solutions or cleaning products. Moreover, it is best to use standard paper towels ­ not super absorbent or those with absorption pockets ­ because they may also carry contaminants that will get left behind on the surface.

Also remember that most film manufacturers have vehicle surface temperature recommendations. 3M, for example, cautions against installation of its films below 60 degrees Fahrenheit. Ambient air temperature should be between 60 degrees and 90 degrees. If the temperature is too cool, move the vehicle indoors to bring its surface temperature up to the minimum. 3M’s Stavreff warns to be aware that if the vinyl is below the recommended application temperature, the following problems could arise.

• Films might not maintain the elevated temperatures required for stretching because they will cool too quickly.
• The initial adhesive bond may be insufficient to ensure adhesion.
• Moisture will condense on the vehicle if its surface temperature is below the dew point.
• In very humid conditions, it may be difficult to keep the substrate dry.

If the temperature is too warm, another set of problems can occur:

• Graphics may pre-adhere, trapping air and causing unsightly bubbles.
• The adhesive will be more aggressive.
• Some films may lose their position-ability feature.
• Films may stretch too easily.

  “After application, keep the vehicle’s temperature above 60 degrees Fahrenheit for as long as possible—ideally for a minimum of 12 hours—before exposing it to cold or moisture,” Stavreff says. “This strengthens the graphic’s bond to the contoured areas.”

  In part two of this two-part series, we’ll delve into design considerations, film handling, a few tips and tricks and how to remove the vinyl so you can move on to the next opportunity.