27 May 2020
Wall graphics have become increasingly popular over the last decade. Higher quality and more affordable large-format printers have enabled sign companies to offer their customers much more than standard signs, vehicle graphics, and posters. Offices, schools, gyms, and hospitals are all benefitting from using formerly blank walls to convey a mission statement, promotional message, or to simply brighten up a space.
However, wall graphics can all too often go wrong, and sometimes very badly. There are a host of complexities that can create potential problems if not considered beforehand, particularly the different types of paint and their compatibility with wall graphics products. Other factors such as incorrect face films and wrong adhesives can also have a negative effect on the end result.
The most common cause of failure is often the lack of a proper site survey prior to installation. A comprehensive assessment should include peel testing potential products to be used, checking the paint at the location, finding out if there are any air conditioning units or heaters in the vicinity and what the local ambient atmosphere is and, if possible, discovering what lies under the paint and when the coat was applied. The more inspection done at an early stage, the better, as there will be a greater understanding of any further requirements for the job or potential ‘danger zones’ to consider in the planning process.
When checking the wall surface during the site survey, sign installers should ensure it is as smooth as possible. A textured surface can add further complexities as the adhesive will reach the peaks of any texture, but is unlikely to grip the troughs. Any defects to the wall should be corrected at this point.
The assessment can also help identify the type of paint used, which becomes an important consideration in the plan of action moving forward—whether the graphics can be directly applied to the façade, or if the wall surface requires further work.
Washable or wipeable paints have become very popular in the past few years. Unfortunately, they do not make for an easy install when it comes to adhesives. Simply put, if a paint has been designed to chemically repel dirt, ink, and fingerprints, it will certainly do the same to any adhesive. If the wall and paint are not prepared correctly, even the highest strength adhesives will fail.
It is often the case when graphics need to be applied to a surface, the wall may have only been painted a couple of days earlier or, in some instances, a few hours before. However, the coat needs to have been applied at least 72 hours in advance—and ideally much longer—to give any adhesive the chance to work.
If the printer has a say in the choice of the graphics to be installed, a basic emulsion paint is always preferable as it has no washable properties. However, if a washable or wipeable paint has been used, there are ways to overcome any potential clash with the adhesive.
Ideally, these paint types need sanding down to remove the ‘washable’ surface. That said, smoothing generates dust—and lots of it—but this is the preferred work-around for this type of paint. If sanding is not a viable option, a good quality sealer or primer could be applied to lock in the washable properties of the paint. It goes without saying whatever the solution, all finishes need to be clean; a seemingly obvious fact that can often be overlooked.
Before commencing the graphics application, regardless of the paint type, installers must make sure the substrate has had sufficient time to bond properly to the wall surface. They must keep in mind any removable adhesive may still cause damage to the paint if the bond is greater than that of the paint to the wall surface, such as plasterboard.
Arranging a site visit in advance can eliminate additional costs and delays. The end-user may not always grant this request, but most will understand that a day’s disruption beforehand is better than several extra days on-site to correct any faults later.
When it comes to producing the graphics, there are a few things printers must consider. While it seems obvious, it is important to check there is enough ink to run the complete job before proceeding. If the liquid runs out during the printing process, there is a high possibility of colour variation.
It is also important to consider the choice of material—the larger the print, the heavier it becomes, so the adhesive needs to be strong enough to hold everything in place.
To commence printing, one must make sure the material is at the right temperature and spin each panel 180 degrees; this will ensure each join prints on the same section across the width of the roll, and the colour will stay constant on the overlaps.
Once the print is complete, sufficient time should be allowed for out-gassing (72 hours minimum) before processing any lamination, cutting, or application tasks.
Printers and signmakers can easily fall into the trap of approaching a wall graphics commission with a ‘one-size-fits-all’ approach when it comes to the choice of media. But, with numerous considerations, including internal versus external application, wall type, graphics size, adhesive strength, and removability, choosing the right media will ultimately determine the success and lifespan of the graphics.
Many manufacturers recommend specific media products that offer excellent performance if the guidelines are followed. For example, a specialized 80-micron polymeric polyvinyl chloride (PVC) film with a high coat weight/strength adhesive is an ideal option for both internal and external applications and is available in matte and gloss finishes. The media makes for an excellent solution for permanent wall graphics and has a very low minimum application temperature of -20 C (-4 F). For external application, one must always check if the media can be applied to brickwork or similar materials, along with the minimum temperature requirements.
Today, a variety of finishes and thicknesses are available along with a unique range of adhesives that allow wall graphics to be easily changed if the image starts to look dated, or if it is no longer suitable.
If a print is being over-laminated, it is important to ensure the chosen laminate conforms to the material it is applied to. One must take the time to research options and, if in doubt, seek the manufacturer’s advice for compatibility as shrinkage, peeling, and disfiguring need to be avoided.
When it comes to fitting, it is crucial to allow enough time for the installation. Many elements need to be considered when applying printed materials and special attention must be given to avoid stretching the graphics. Anything that is disfigured will want to reconfigure back to its original state, decreasing adhesion and ultimately deforming the graphics.
The simple task of removing the liner can also play a factor in the success of an installation. It is recommended one removes the liner from the face film rather than the face film from the liner. This will reduce stretching, which could otherwise damage the overall impact of the finished graphics.
When installing the final product, it is important to plan the positioning of overlaps in advance, as these will be crucial to the result and the ultimate impact of the graphics. Deciding which panel gets fitted first will determine the way the overlaps will be seen, which is especially relevant when positioned near a door or entrance to a room.
Wall graphics present a great opportunity for printers by transforming a space without necessarily committing to a permanent change. However, for this benefit to stay in place many factors need to be considered, such as wall surface preparation, type of paint, and the type of adhesive on the print media. After all, the success of the installation lies in the preparation.
Dave Newbery is a regional sales manager for Drytac Europe. He has spent more than 30 years in the wide-format industry in sales and management. Newbery has worked for both distributors and manufacturers and has an in-depth knowledge of print media and equipment. He can be reached via email at email@example.com.
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