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Saturday, April 21, 2012

The Right Overlaminate for Vinyl Signs & Vehicle Graphics

By Jim Hingst

Each type of overlaminate has its own  unique properties. In selecting the right overlaminate for a specific application, this story reviews your options.

Selecting the right overlaminate for a particular graphics application requires just as must consideration as selecting the right digital print media.  And for many, it can be just as confusing, if not more so. For starters, just page through any distributor catalog, and you will find a wide array of options, nearly as extensive as your media choices.


With all that’s available, how do you pick the best one for the job? As self-help guru Anthony Robbins instructs: “If you want better answers, learn to ask better questions.”  In selecting the right  overlaminate, here is a list of questions for you to consider: 

1.   What is the application? It's important to pick the right film for the job. Whether the task involves floor graphics, perforated window graphics or fleet markings will dictate the appropriate overlaminate.

2.   What substrate will receive the graphics? Will it be smooth, such as flooring, an acrylic or polycarbonate sign face, or will the graphics be applied over rivets or corrugations?

3.   What environment will the graphic  be subjected to? Will there be temperature extremes, UV light, water or pollution? Will it be subject to acidic or alkaline cleaning agents, or could it be exposed to vandalism, grease or road salts?

4.   Under what lighting conditions will the graphic be viewed?

5.   What are the job's durability requirements?

6.   Is the overlaminating film compatible with other components of the graphics system?

Answers to these questions, will help you select the right overlaminate for your particular application. Before you make a decision, you need a good understanding of the types of overlaminates available.  The range of products to choose from includes a variety of facestocks: polyester, polypropylene, polyvinyl fluoride (PVF), polycarbonates, and cast and calendered vinyl. Picking the best overlaminate requires matching product performance characteristics to the application’s demands.

Fleet Graphics. 

Fleet graphics can take a beating from acidic and caustic chemicals, to the bleaching effects of summer sun, scratches from low hanging branches, and the sandblast effect of dirt and sand as a vehicle rumbles down the road.   

These environmental extremes necessitate that you protect all printed vehicle graphics with either a liquid clear coat or an overlaminating film.

In selecting an overlaminate for vinyl fleet graphics, the general rule of thumb is: use a cast vinyl overlaminate for cast vinyl graphics; use either a calendered or cast overlaminate for calendered vinyl graphics. 

Screen Printed Fleet Graphics. 

When choosing an overlaminate for screen printed fleet graphics applications, test the components before using them in production. Because screen printing deposits an extraordinarily thick layer of ink,  these printed graphics typically require an overlaminate with a heavier coating weight of adhesive. An overlaminate with a thin adhesive coating will bridge the edge, causing a slight, but noticeable, air pocket.

Large, laminated graphics should be covered with a heavyweight, low-tack premask. This masking prevents scratches in the overlaminate during installation. It also prevents vinyl graphics from stretching during the application process. Even a laminated graphics can stretch like a piece of warm taffy, when applying graphics in hot weather.   If you are installing a fleet graphic, with multiple panels and one panel stretches, you may need to play some games to get the multiple points of alignment to match from one panel to the next.


Transit Markings. 

Public vehicles, such as buses and train cars, are common targets of marauding vandals armed with cans of spray paint. To protect vinyl graphics from this urban artistry, expensive polyvinyl fluoride (PVF) overlaminate films provide the utmost protection.

Because PVF is a low-energy plastic, paint has difficulty sticking to it. These films, which also provide excellent UV and abrasion resistance, are ideal for graffiti-proof markings, but because these films don’t stretch, they can be used only for flat applications. 

PVF’s anti-graffiti properties don’t last forever. If solvents are used to clean vandalized graphics, the cleaning chemicals can etch the surface.  The result is that the next time the graphic is spray painted,  complete removal of the graffiti may not be possible. As an alternative to solvents, try cleaning tagged graphics with a nylon-bristle brush and citrus-based cleaner, such as Simple Green®.

Perforated Window Graphics. 

Some vinyl companies recommend or require an overlaminate with their perforated window-graphics film. This precludes using application fluid, because fluid would be trapped inside each little hole.

So why use an overlaminate at all? Failure to use an overlaminate on perforated window graphics films, can result in problems.  An overlaminate protects the printed image from the degrading UV rays of the sun, thereby increasing the useful life of the graphic.   Without an overlaminate,  dirt can collect in the holes, which can cause the edges to lift. An overlaminate also prevents the film’s holes from filling with water, when it rains, obscuring vision through the graphic in a storm.

For  store windows or other flat applications, you can use a polyester overlaminate.  Curved surfaces, however, require the use of a cast vinyl overlaminating film. Following graphics application, you should coat the edges of the graphic with a commercial edge sealer.

Tankers and Cement-Trucks. 

Clear coating provide great short-term protection for signage and promotional pieces, but they don’t outperform overlaminates for demanding applications. Graphics on chemical tankers are frequently subjected to chemical spillage. Acids, caustics and solvents can quickly erode the ink and clear coat system of printed fleet markings, as well as leech the plasticizer from pigmented vinyl, embrittling it and causing the film to crack. Cement-truck graphics, which are easily damaged by caustic cement and harsh cleaning chemicals, should also be overlaminate-protected.

Although vinyl overlaminates are usually best for vinyl markings, chemical tankers and cement trucks are an exception. For protecting markings subject to chemical damage, a polyester overlaminating film was the best choice 30 years ago, and remains so today.

Shortcomings of Polyester Overlaminates. 

While polyester overlaminates exhibit outstanding chemical and temperature resistance — features that also make it an excellent protective film for warning labels. But, because polyester isn’t conformable, it can’t be used over rivets, corrugation or compound curves.

Graphics laminated with polyester require special handling. To prevent tunneling, delamination or bubbles between the overlaminate and base film, graphics are best stored and shipped flat. During installation, take special care to avert delamination.

Furthermore, to prevent edge lifting, graphics applied to the surfaces of tankers that haul caustic or petroleum-based products should be coated with a commercial edge sealer.

Floor graphics.  

Because floor graphics must withstand extraordinary abuse from pounding foot traffic, dirt, grease, grit and chemical cleaners, polycarbonate overlaminates are the best choice for these demanding applications. Not only can this tough, resilient film withstand heavy daily traffic, its matte texture prevents slippage.

To ensure that a floor graphic is slip-resistant, overlaminates are rigorously tested. One industry standard is American Standard for Testing Materials (ASTM) D2047.

This ASTM test checks the overlaminates’s coefficient of friction, the force required to move one material over another. In essence, the test measures the traction a pedestrian could expect as he or she walks on a floor graphic.

Installation Tip: Following application, all floor graphics should be waxed with a product recommended by the film manufacturer to prevent edge lifting.

In-Store, P-O-P and Exhibits. 

As digital printing has grown in the sign industry, so has the use of overlaminates for signage, interior-wall and tradeshow graphics, and P-O-P applications.

Thick polycarbonate overlaminates are also often used for the protection of exhibit materials. These rigid films are available in a variety of thickness. 

In engineering tradeshow graphics, a good practice is to select  materials (media, backer and overlaminate), which when laminated together will provide a construction, which is at least 20 mils thick.

Polycarbonate overlaminates are well suited for exhibit and display graphics because they provide excellent lay-flat characteristics, and their velvety texture eliminates any glare from overhead lighting. Polycarbonate can also withstand the rough handling encountered when rolling and unrolling tradeshow graphics.


Conclusion.   

In selecting the right overlaminate for  a job, the most important consideration is the application.  To keep your customer happy, also make sure that you understand your customer’s expectations and any special requirements of the job.  To get the answers you need, ask questions – plenty of them. 

For more information about overlaminates and  vinyl graphics, refer to my  book, Vinyl Sign Techniques and the Graphic Installers Handbook by Rob Ivers.




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Vinyl Application Videos

Squeegee Technique. Nothing is more basic in vinyl application than the squeegee. But some squeegees work better than others. And there are right ways and wrong ways to use this simple tool. This video clip reviews squeegee selection, squeegee care and squeegee technique. Click to Link

Wet Applications. Dry applications are typically recommended for most vinyl applications. For those exceptions to the rule, this instructional video explains the right way to perform a wet application. Click to Link

Application of Window Graphics. Installing vinyl graphics on glass can be challenging, because the adhesive aggressively grabs onto this high energy surface. Repositioning graphics on window is generally difficult, if not impossible. This instructional video explains how to dry apply window graphics right the first time. It also describes the necessary steps required for surface preparation. Click to Link

Transferring Frosted Window Graphics Films.  Because frosted window films are highly textured, transferring cut vinyl graphics can be problematic. This video provides direction in selection of the right application tape and how to apply these films quickly, easily and without problems. Click to Link

3-Step Surface Prep. This instructional video describes how to properly clean the surface of a vehicle before applying pressure sensitive vinyl graphics to a trailer or doing a full wrap of a car or van. This three step surface prep involves detergent washing, solvent cleaning and a final wipe down with IPA. Click to Link


Vinyl Application Over Rivets. Applying vinyl graphics on vehicle surfaces with rivets is challenging for most sign makers. Vinyl failures to these surfaces are all too common. This video demonstrates some tips and procedures, used by professional decal installers, which will make these demanding applications easier and more trouble-free.  Click to Link

Vinyl Application to Corrugations. Learn how to apply vinyl graphics to corrugations in a relaxed state. Forcing films into the valleys of corrugations puts too much mechanical stress on the film. Sooner or later, the vinyl will lift or tent in valleys. Click to Link

Applying Air Egress Vinyls. Vinyl films with air egress release liners have almost eliminated bubbles and wrinkles from applied graphics. Air egress release liners with their highly textured surface structure are problematic. Not much will stick to these liners other than the vinyl film. At RTape our best premask solution for air egress liners is a special Conform® tape called 4761RLA. Click to Link

 Do You Have Questions or Comments?

About Jim Hingst: Sign business authority on vehicle wraps, vinyl graphics, screen printing, marketing, sales, gold leaf, woodcarving and painting. 

After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.

Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer.  Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.

Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for  publications, such as  Signs Canada, SignCraft,  Signs of the Times, Screen Printing, Sign and Digital Graphics and  Sign Builder Illustrated. He also posted more than 500 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published.  Vinyl Sign Techniques is available at sign supply distributors and at Amazon. 



© Jim Hingst 2018

2 comments:

  1. it can be just as confusing, if not more so. For starters, just page through any distributor catalog, vinyl window graphics printing

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