In selecting an overlaminate for vinyl 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.
Calendered vinyl, is not appropriate for a vehicle wrap with curved surfaces,
especially one with as many curves as the bumper on a car. The reason is that calendered vinyl films have memory. If you stretch a calendered vinyl, it tends to spring back to its original shape.
For curved surfaces,
such as those that you encounter when performing a vehicle wrap, you should always
use a cast vinyl overlaminate. Cast vinyl films not only have the ability to stretch, but will also shrink when
need. This probably sounds a little
strange to you. So let me explain.
When you apply vinyl film to a concave surface, you must
stretch the film so that it can reach into the corners. Keep in mind that when you stretch something
it becomes thinner. Using cast vinyl
media with a cast vinyl overlaminate is
the right product solution for this application.
Cast vinyl films possess very little mechanical stress,
because of the way they are manufactured.
In applying these films, you typically heat the material to make the
film more pliable so you can stretch it when you need to, but also to break the
memory of the film.
After you have
applied the film, you should also post heat the graphic using an industrial heat gun, such as a Steinel Programmable Heat Gun.This secondary heating process locks the film
in place. Failure to properly heat the vinyl film often leads to the film
failing.
When you apply vinyl wraps to a convex surface, such as
the corner of a bumper or the radius at the end of a van, you do not stretch
the film to make it conform. Instead,
you typically have an excess of material.
In photo A below, you will notice the extra film that has accumulated as I am applying the graphic. In this situation, I have more film than I need. Trying to stretch the film is no solution and will only make matters worse. How can you eliminate this extra film? Rather than stretching the vinyl wrap, I must shrink it, again using an industrial heat gun.
In photo A below, you will notice the extra film that has accumulated as I am applying the graphic. In this situation, I have more film than I need. Trying to stretch the film is no solution and will only make matters worse. How can you eliminate this extra film? Rather than stretching the vinyl wrap, I must shrink it, again using an industrial heat gun.
In photo B
below, I am using a heat gun for this
shrinking process.
As the vinyl wrap film is heated, it contracts. Instead of the vinyl film becoming thinner, as it does when you stretch it into a concave surface, it
actually becomes thicker. In a way, when you heat the vinyl graphics to make it contract,
you are shrink wrapping the vinyl onto the car surface. See photo C below. Voila! Magically the
excess material disappears. A cast vinyl film with a cast vinyl overlaminate
has the flexibility to respond to heat in this manner.
While vinyl graphics made with a cast vinyl film have the needed
conformability characteristics, other plastic films do not. While sign makers
frequently use calendered films and calendered overlaminates for vehicle
graphics, in most cases, they are the wrong films for the application.
In
comparison to the manufacturing process used to make cast vinyl films, calendered vinyl films are forced through a series of gigantic rolls, which stretch the
material and induce tremendous mechanical stress into the film. Heat these vinyl graphics all you want, and you will
never completely break the memory of the film. When used for applications, such as vehicle wraps, and these vinyl graphics often
fail, pulling away from the surface to which they have been applied.
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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
About Jim Hingst: 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 325 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.
© 2016 Jim Hingst
I really enjoyed reading this article, and found it quite informative. And especially the part about wrapping the vehicle. Thanks for sharing! I generally prefer RTS for vehicle wrapping in london and would recommend it to all.
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