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Much can play into the success of an application and how long the graphic will last: The properties of the vinyl product, the chosen type of adhesive, the conditions under which the graphic is being applied, and the propensity of the installer to follow proper procedures. Even a seasoned installer using the best materials on the market could be doomed to relative failure before an application is even begun if they do not appropriately execute one specific step.

No matter what the circumstance, graphics are always being applied to some sort of surface, and if that surface is not properly prepared, there is a distinct possibility that the graphic will not last as long or look as good as it should.

Surface preparation is a critical step toward attaining successful, long-lasting vinyl graphic installations, but it is one that is unfortunately often overlooked and misunderstood. Simply because a substrate does not look dirty, wet or otherwise compromised does not mean that cleaning and preparation of the surface is unnecessary. Also, not all substrates should be prepared in the same manner; there are specific steps that should be taken based on the composition of a surface. For these reasons, it is important to understand principles of cleaning and preparing various surfaces for optimized pressure-sensitive graphic applications before attempting them.

Preparation and Cleaning: The Basic Steps
As is the case with most any procedure, a great place to start when preparing for a graphic installation is reading the directions. Especially when using solvent-based cleaners, review all instructions on the container, and contact the manufacturer, if necessary, for clarification regarding ventilation, use and disposal. Be sure to wear gloves or other personal protective devices (PPDs) as recommended by the manufacturer's guidelines and warnings.

While you may not need a lot of tools in the surface preparation stage of installation, make sure what you do use is helping, not hindering your cleaning. As towels or cloths become dirty, use new ones. Make sure all surfaces are completely dry prior to application. If need be, use a heat gun to remove moisture, especially around rivets and along seams. Always reference applicable performance guides provided by graphic material manufacturers for appropriate application temperatures.

As you begin, you should have two basic goals in mind when cleaning a surface before graphics application: Removal of organic contaminates, such as dirt, bug spatter or food residue, and removal of petrochemical contaminates, such as wax, grease and oils. To properly remove these contaminates a three-step process is recommended:

STEP ONE: Remove organic contamination by washing the surface with a commercially available detergent and water (one tablespoon per gallon) and a lint-free cloth. A good automotive or dish soap used sparingly in the water works well. Do not use soaps containing creams, waxes, oils or silicones - this includes some window cleaners - as these will further contaminate the surface. When finished, dry the surface with a soft, clean, lint-free cloth and allow porous materials to dry completely.

STEP TWO: Remove petrochemical contaminates with a lint-free cloth soaked in a solvent-based cleaner. Weak solvents, such as glass cleaners or alcohol, will not remove many contaminates, but strong solvents, such as paint thinner, acetone and toluene, may damage the finish. Always test solvents first in an inconspicuous area, and use a clean, lint-free cloth to dry the surface prior to evaporation.

STEP THREE: Wipe down the area with isopropyl alcohol (IPA) using a clean, lint-free towel, just prior to application to remove any dust, solvent or detergent residue left on the surface. If you are using industrial-grade IPA, mix it in a ratio of two parts IPA to one part water. If you are using rubbing alcohol, do not dilute.

Study Your Substrate Specifics
While the three steps listed above are good general guidelines, it is important to remember that not every surface type is the same, and thus these preparation guidelines must sometimes be altered accordingly. The following is a list of substrate categories and some of the points to keep in mind during cleaning. For a more comprehensive list with additional material specifics, contact your graphic product manufacturer. No matter what substrate you are dealing with, always test first for suitability before you begin surface preparation.

Metals
An important category for vehicle wraps and certain environmental graphic applications, the recommended preparation for metals varies according to the metal composition and treatment. Stainless steel, for instance, can be cleaned using the basic three steps listed above, but untreated or unpainted "base" steel should be refinished and painted before graphics are applied. Oxidation of a metal, the method by which it is galvanized or anodized, and other properties of the surface will determine whether additional steps are necessary to prepare the surface for graphics installation. Also, know that not all metals are recommended for graphics installation, including brass, copper, lead, magnesium and tin.

Wood
Wood contains a certain amount of natural moisture and will absorb moisture from the atmosphere if not properly sealed first. Therefore all surfaces, including both sides and all edges, must be coated with a high-quality paint or sealant - one that does not purposely chalk, bleed or contain ingredients that migrate to the surface. Interior wood surfaces must be at least primed, and exterior wood surfaces must be primed and painted on all exposed surfaces, including edges. Use good quality paint designed for wood surfaces to ensure good adhesion, and avoid matte or flat-finished paints. Whether you are preparing hardwood or plywood makes a difference, as does the grade of plywood. Be sure to fill all holes, smooth surfaces, and seal edges as necessary.

Plastics and Rubber
There are many polymer types that fall under "plastics," so be sure to know exactly what material with which you are dealing. Some polymers, such as polystyrene and styrene, react badly to strong solvents. Others, such as polycarbonate and fiberglass, should be tested for outgassing due to moisture trapped close to the surface of the material. Whereas polyethylene and polypropylene can be cleaned using all three basic steps we have outlined, Step Two should be skipped in the case of acrylic, acrylonitrile butadiene styrene (ABS) or polyethylene terephthalate (PET). Rubber and caulking materials are not recommended for graphic application, as films typically have poor adhesion to these materials.

Painted Surfaces
While any surface material could be painted, it should always be thoroughly cleaned and coated with a strong bonding primer. Paint finish should be semi-gloss or satin for best adhesion results. Allow paint to thoroughly cure prior to graphic application, and follow paint manufacturer's recommendations for curing. Allowing a minimum of one week at nominal temperature and humidity is a good rule by which to abide for curing.

The type of paint used can determine how soon after painting a graphic application will likely be successful - two-part urethane paint systems, for instance, may require a day or two of waiting to allow for outgassing. Certain paints, such as powder-coat paint, may require special adhesives for a lasting application, and there will be some variance regarding how many of the basic three cleaning steps should be executed based on paint type as well. In general, you should avoid using:

Oil alkyd primers or paints (as these may take months to dry)
High-matte latex paints
Highly pigmented or flat metallic paints (which tend to chalk or bleed)
Paints that purposely include ingredients that migrate to the surface, like waxes, silicones or antifouling or antifungal agents (which may be categorized as "easy clean")

Building Materials
Especially applicable with wall or floor graphic applications, building materials such as drywall, concrete, wall coverings and fiberglass-reinforced plywood (FRP) also require specific cleaning considerations. This category encompasses a number of very different material types, so it is important to know their individual quirks. For example, it may be necessary to remove any dust or chalkiness before cleaning and to seal or paint surfaces in some cases, but not others. FRP does not react well with strong solvents; graphics should never be applied to unsealed drywall, and bare concrete does not facilitate good graphic film adhesion without a special adhesive surface. As a rule, it is prudent to check with a graphic product manufacturer before making any assumptions about building material preparation.

Miscellaneous Surfaces
There are other surfaces to which you might wish to affix graphics that have not been covered yet, such as paper-based posterboard, glass, porcelain or banner material. With something paper-based or foam-based, you likely would want to avoid application of liquid to the material, and thus dust removal may be the only cleaning necessary. For glass or porcelain, the standard three-step approach to cleaning will work, though size, thickness, quality of cut, edge treatment, tinting and frame design could affect temperature stress caused by sunlight on dark areas of a graphic. This, in turn, can cause breakage in some cases, so keep this in mind when positioning. Banners typically only require an IPA wipe down.

Beyond Cleaning: An Application Checklist
As referenced earlier, surface preparation is just one aspect, albeit an important one, of a successful application. There are also other considerations that should cross your mind before a graphic is installed, such as:

What sort of application is this?
Do I have the right sort of graphics material and adhesive to make it last in these conditions?
Will this be an interior or exterior application? How will this factor into graphic longevity?
What is the estimated viewing distance of the graphic?
What are the material and texture properties of the surface to which my graphic will be adhered?
How long do I need to wait between surface preparation and applying the graphic?
What is the expected application temperature and environmental conditions that could affect installation?
Will the graphic need to conform to curves or rivets?
Who is installing the graphic? Will it be a professional?
Who is removing/repositioning the graphic? Will it be a professional?
Will there be a need for ongoing cleaning of the graphic? If so, who will do this?
Are there any other unique application characteristics that could affect the installation?

The answer to any of these questions could affect the way a graphic should be applied, the type of materials that should be used, and how long a graphic will last. For instance, if you are working with a textured wall or floor surface, you may need to use a product specifically designed for these applications, such as MACtac®'s RoughRAP™ or StreetRAP™. If you are applying a vehicle wrap, the amount of curvature involved could determine which type of bubble-free digital media you ought to use. If you are applying a graphic to drywall, you may need to wait until the paint is fully cured - something that may take upward of 90 days with a heavily pigmented paint.

Overwhelmed? Rely on the Experts
There are clearly many factors that affect cleaning and application practices. The considerations listed thus far do not fully account for the thought that must go into graphic material and adhesive choice, which can be affected by environmental elements acting on a graphic, the surface type to which adhesion must take place, desired repositionability of the graphic, possible lamination of the graphic, and more.

Pressure-sensitive graphics application may seem simple to the uninitiated, but there is clearly a lot to it. For this reason, it is always a good idea to stay in close contact with your graphic material supplier, as they should be experts on all facets of graphic application, from material choice to installation best practices. Some companies have even created online communities through which installers can learn from one another and access media that conveys the latest tips and tricks being using in the field, such as www.theapplicationnation.com.

Armed with support from the people who know graphic installation and properties best, as well as a dedication to remembering that it all starts with surface preparation and cleaning, consider yourself well equipped the next time you set out to achieve the perfect graphic application.

Jason Yard joined MACtac in 2007. With expertise in graphic design, printing and installation, Yard is responsible for marketing to MACtac Graphic Products' large customer base and training them on the details of application techniques. Leading MACtac's well-known Application Nation program, he focuses on educating customers on the best uses for MACtac's products, matching products to applications and proper installation methods. He also assists and facilitates MACtac Graphic Products' research and development and new product benchmarking. Yard holds a Bachelor's degree in Visual Communication Design from Kent State University.

Images courtesy of MACtac/Morgan Adhesives Company.

This article appeared in the SGIA Journal, September / October 2013 Issue and is reprinted with permission. Copyright 2013 Specialty Graphic Imaging Association (www.sgia.org). All Rights Reserved.