Applying Oracal 631 – Mask it, Heat It, and Flip It

As residential and commercial wall graphics become more popular, many people are turning to Oracal 631 to produce indoor graphics. Oracal 631 Exhibition Cal is a 3mil calendered vinyl designed specifically for indoor use. Its name indicates its intent as a graphic marking film for indoor trade show and exhibition graphics. 631 has two unique properties that make it ideal for these kinds of applications: a removable adhesive and a matte finish.

Because these graphics are generally temporary, 631 is the only Oracal decorative plotter film with a removable adhesive. All other Oracal plotter films are designed for medium to long term outdoor use and feature a permanent acrylic or solvent adhesive. Because of its removable acrylic adhesive, graphics applied with 631 can be removed cleanly with little or no residue.

The other feature that distinguishes 631 from the rest of the Oracal line is its matte finish. Generally, Oracal plotter films offer the highest gloss levels in their segments. With 631, Oracal goes in the other direction by offering 48 colors in a matte finish. This is appropriate for a vinyl designed for corporate communication in the brightly lit world of convention centers where a graphic rendered in high gloss vinyl might not be as legible as it should be.

The cloud to the silver lining of 631’s matte finish is difficulty achieving release from the Kraft paper liner.  Typically, Oracal vinyls require the use of high tack transfer tape because of their dense face stock. High tack tapes such as R-Tape 4075 or Main PerfecTear Plus work very well with Oracal plotter films.  But even high tack tapes have trouble with 631 Exhibition Cal. There’s a good reason for that. And there’s a simple solution.

The reason for the release resistance is 631’s matte finish. That lovely low gloss color is achieved by giving the vinyl a slightly rougher surface that breaks up light reflection. That coarseness is too fine to be felt by your fingers, but is enough to degrade the contact area between the tape’s adhesive and the surface of the vinyl. This weakens the bond between the application tape and vinyl, making it difficult for the tape to get a grip.

The simple solution is heat. To achieve a better bond between the tape’s adhesive and the vinyl’s surface, simply heat the tape after you’ve masked the vinyl. This softens its adhesive and makes it more malleable so that when you squeegee the tape onto the vinyl, the adhesive fills more of those little gaps, resulting in a stronger bond between the tape and the vinyl’s face stock. The result is a smoother, easier release.

This can be done with a standard issue heat gun or even a good quality hair dryer. Since we have lots of housewives who use Oracal 631 with their Craft ROBO and Cricut cutters for scrapbooking and hobby applications, I wanted to come up with the simplest possible solution.  So I borrowed my wife’s Remington ProAir 1875 (an 1875 watt blow dryer) set the heat to “high”. Here’s the process in four easy steps.

  1. Heat the masked graphic for two minutes, holding the dryer or heat gun about 2 inches from the tape.
  2. Apply pressure with a squeegee to force the tape’s warm adhesive into the 631’s textured face stock.
  3. Turn the masked graphic over, set it flat on the table, and peel the liner backwards, away from the tape. It will come off cleanly and easily.

Step three is very important. Many Oracal vinyls resist releasing because of their denser face stock. This is especially true of thinner vinyls like 651 Intermediate Cal.    Adopting the “Oracal flip tip” has made life easier for lots of our customers.   Heating the tape before you flip the vinyl will produce the same happy results with 631.

The heat gun idea occurred to me as some of our managers were discussing  631’s unique properties with our Oracal representative. As crafty and creative as sign makers are, I’m sure there are other ways to approach this problem. If you have an application trick that you’ve found helpful in your shop, feel free to share it in the comments. And let us know if you find this tip helpful.