By Melissa Donovan
Window graphics offer a purpose as well as an aesthetic. Depending on the type of material used, a digitally printed window graphic provides privacy, retains heat in a building, and showcases a brand’s motto or a recent promotional sale.
Media designed for window applications can be wet or dry installed. This article examines both and determines when it is best to use one over the other, as well as the challenges and advantages of each.
Above: FLEXcon’s seeTHRU-sign product line includes perforated window films. This application was printed and installed by E. H. Teasley & Co. & Inkjet International.
Wet and dry application of window media are the two main techniques. Choosing one over the other depends on a number of factors, including installer preference and environmental conditions.
Gareth Newman, academy manager, Drytac, says “which application method used can be narrowed down to the experience of the installer, location, size of graphic, and how complex fitting could be.”
“Wet and dry techniques can be used in almost any window application. You want to determine what is best for you as the installer—think about what’s the environment you’re installing in, how large the job is, what the customer’s budget is, weigh the time it will take with both application options, and what film is being used to see if wet application fluid can be used,” recommends Michael Aldrich, product manager, FDC Graphic Films, Inc.
Environmental situations play an important role. “Conditions of high heat and humidity can cause moisture to get behind the graphic being installed, which will interfere with the adhesive wet out and bond. High heat may cause a higher tack adhesive to exhibit higher initial tack, making rework more difficult,” advises Bekie Berg, product manager, FLEXcon Company, Inc.
In regards to wet installation of graphics on windows, the premise is that when using application fluid or water, the graphic is able to be slid around to achieve perfect positioning—before squeegeeing out the liquid, explains Matt Edwards, product manager – digital print media, General Formulations.
This process is referred to as “floating” the graphic on the surface, notes Ross Burnham, senior marketing manager, Mactac. Projects that incorporate intricate patterns of cut vinyl utilizing a pre-mask benefit from a wet application process. Similarly, Burnham says the same approach is used for window graphics that are optically clear.
“When installing optically clear window films, a wet install gives bubble-free results, as the installer can easily squeegee out any air bubbles during the installation process,” agrees Wayne Colbath, national sales manager, Continental Grafix USA, Inc. He adds that wet applications are typically completed when products feature an adhesive backing that does not egress air efficiently.
“Products without air egress will have air bubbles without a wet application. An experienced installer may be able to accomplish this dry but a lot of extra caution is necessary to ensure all the air between the window and the adhesive surface is removed. Air egress window films automatically remove excess air bubbles,” explains Edwin Ramos, director of sales, GBC SEAL, a division of ACCO Brands.
A dry installation, argues Edwards, requires a little more preparation and precision. “Relying on the hinge method and application tape to align and install.”
Prior to applying a window graphic using dry installation, “extra care must be taken to ensure that the glass is perfectly dry,” advises Doug Phelps, business development manager – architectural films, Avery Dennison Graphics Solutions.
Berg notes that the dry method is more suitable for cold weather installation, installing mid day on a sunny day when possible. “This allows time for the window to warm and will provide the best possible outdoor conditions.”
Dry application makes sense for materials where the air egresses naturally, the media has an repositionable/removable adhesive technology, or where the construction/engineering of the media is not conducive to wet installation, for example perforated window films, explains Colbath.
“The same channels that allow air to easily escape from the graphic would also trap application fluid, creating an issue with appearance and potential adhesive failure,” warns Burnham.
Window type and size is also influential. Phelps notes that wet installation is actually easier on larger windows.
Aldrich agrees. “The larger the window, the easier it can be to use a wet application. A colder temperature can dictate application, or you can use a low temperature application fluid. Air egress may be able to be applied at lower temperatures and these window films don’t need wet application fluid.”
“Typically the decision to install wet or dry is based on the size of the project and the availability of an installation team. Larger projects almost always install wet. Retail stores with multiple locations that are advertising for a specific campaign are ideal places to use a dry apply window graphic,” advises Jim Halloran, VP sales and marketing, Lintec of America.
There are scenarios where both the media and the window combined dictate the type of installation technique used. “If you have a high grab adhesive on a optically clear PET that is very large, most likely you would use wet as this gives you a chance to line up the panel in the desired location and take your time applying the graphic making sure that there is no trapped air or water, which destroys the overall appearance of the window. However, if the graphic is smaller and manageable then dry installation might the best way as there is less mess and the install is quicker,” admits Newman.
Wet Method Specifics
There are pros and cons to every application technique and window graphics are no exception. The list of advantages and disadvantages for wet installation is a bit more lengthy than dry application, as there are more variables at play like the application fluid, media, adhesive, and window.
“The advantages to wet are ease of air egress, as well as ease of repositionability during installation. Also, it really provides unmatched quality when working with any optically clear film, or films where view through is desired,” notes Colbath.
Visually, the wet application method ensures a clear view—when completed properly. “Wet application allows a clean installation of media that can be optically clear. The air release channels that allow a media to be dry applied increase the amount of hazy appearance in a clear film. So this is a consideration when choosing media. Determine how much of the media is going to be printed or a solid color to look at, rather than looking through the glass,” advises Jen Daly, application engineer, 3M Commercial Solutions.
“A benefit for complex cut graphics utilizing the wet method is that 100 percent of the adhesive is contacting the glass surface. This increases the durability of the finished piece, increasing the useful life of the graphic,” says Burnham.
Challenges here involve the application of the media itself, as the process is more involved. According to Nekoosa, when applying using a wet method, it is preferred to lightly mist the substrate with application fluid—using the least amount of fluid to accomplish the application process is key. It’s important to note that spraying the adhesive side of the graphic with application fluid is unnecessary, unless applying large panels. Spraying cut vinyl letters with fluid can also cause the lettering to loosen up on the application tape or cause the lettering to fall off.
The application fluid in question needs to be vetted, especially in regards to how it will react with the media’s adhesive. “Adding water with solvents or surfactants can negatively impact the adhesive. For example, clear vinyl decals with water-based adhesives can turn cloudy 24 to 72 hours following application as the adhesive reacts to the liquids. Some window fluids will actually break down the adhesive and can cause failure as they outgas or disrupt the bond, leaving residue behind upon removal,” warns Edwards.
“If the film has a water-based adhesive it is not recommended to use wet application fluid because this could cause the adhesive to get cloudy,” says Aldrich.
According to Berg, a wet solution should contain either an approved application solution or a mixture of four to six drops of Joy detergent to one gallon of lukewarm water. She does not recommend using soap that contains lotion, cream, fragrance, or ammonia as they can interfere with adhesion.
“Installing with a warm water, soapy solution will allow the installer to slide the film around and get a nice seam if necessary,” suggests Halloran.
It is also important to allow time for the graphic to dry out and the adhesive to fully bond before making the final trim. “If you begin to trim your graphic before the leading edges have the chance to fully dry out and cure, you could accidentally pick up the graphic and create a peel line in what was an optically clear adhesive,” notes Newman.
“It’s critical to ensure all the water is removed from behind the graphic. This requires working out from the center to the edges and wiping the edges to be sure no water is left behind. The use of an application tape is not recommended with the wet method. The adhesive will take longer to bond and removal of a tape that has stronger adherence to the graphic than the graphic to the window may cause the graphic to lift upon removal of the tape,” adds Berg.
Dry Method Specifics
The dry method of application is fairly straightforward with the media and the window the players in the process. Without an application liquid, a major step is eliminated, but that doesn’t mean dry application doesn’t have its own challenges.
Burnham notes that “graphics designed for dry installations are helping the untrained local employee to be successful in putting up these prints, many times without the need for any specialized tools.”
“The advantage of a dry application is that air egress films can be applied in lower temperatures in some cases. Also, there is no wet mess, which saves money and time, and there are repositionable adhesive options,” adds Aldrich.
Reinforcing that dry apply is preferred for perforated film materials and products with an air egress liner, Berg says that the suggested application temperature is 40 to 50 degrees Fahrenheit unless otherwise specified by the manufacturer.
“Proper alignment is critical because minimal rework is possible with the dry method. Also, air bubbles may appear under the film and can take time to remove,” she continues.
There is no overwhelming answer to whether dry or wet application is better than the other, especially in regard to cost effectiveness. As mentioned before, many factors are involved in the final outcome and the installer’s experience level is also paramount here.
“Talented installers can be equally profitable with either method, working with a range of materials and producing a quality installation. As with everything, practice makes perfect, and consistent quality with experience can overcome minor cost differences in materials,” notes Edwards.
Halloran suggests a wet apply method with a professional installer if the project involves an entire building or a series of conference rooms, for example. “Professional installers are very efficient, can be in and out of the office in a day, and give the most professional affect.”
When it comes to working hours—time spent installing and then having the job be officially in use—Phelps argues that dry installation will be faster. “In general, dry installation allows you to activate the film immediately after application. While for the wet installation, it will be necessary to wait for 12 hours after installation, adding up on the working hours needed to complete a job. That might affect the installation costs, especially in smaller projects.”
Dry application means “less time required on site, less mess, less equipment and steps, but more experience is required to complete larger graphics,” agrees Newman.
Ramos believes this translates to dry apply repositionable being less expensive because it “requires less skill and no tools to install and position it.”
“The dry application method could be more cost effective because the need for application fluid is eliminated and clean up is minimal. However, the cost of the dry application film may be more due to the adhesive technology allowing the ease of application. This is where you weigh the time and extra supply cost with a wet application,” proposes Aldrich.
As such, Berg advises that it is best to balance everything based on “performance, installation time, and material cost combined. If dry method installation is possible without taking too much time or rework, it may be the most cost-effective solution, even if it costs more in material. Wet method, if done properly, may allow the installer to work faster—saving time and costs. Weighing all of the factors—graphic size, material type, environmental conditions, and access to the windows—is important when determining which method may be most cost effective.”
Install Any Way Today
Dry and wet application methods for window graphics are used. Which technique is chosen depends on the installer’s expertise, size of the window/graphic, type of media, and environment the graphic is placed in. Each process offers its own set of challenges, but when done correctly provides a stellar appearance.
Nov2021, Digital Output