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.


  1. what do you mean mask it?

  2. Hi Wendy.
    "Masking" is just another term for covering the vinyl graphic with a sheet of tape after you've cut and weeded it. The tape is also called transfer tape because it's used to transfer the vinyl graphic to the intended surface.

  3. Can you use a wet application when applying oracal 631 to glass?

  4. Yes but, since ORACAL 631 has a water-based adhesive application fluid should be used very carefully if at all. Use only as much as you need to moisten the surface and squeegee it out from under the vinyl as soon as you have it positioned where you want it. Then allow about 15 minutes for it to dry before you try to remove the transfer tape, and expecit it to take a little longer for the adhesive to bond completely.

  5. Are you saying that the only way to get a good contact to the masking is that I have to heat EVERY decal that I send out of my shop?…seriously?…I was considering this product for a new line of items, but not sure now. Has anyone had any success with just using a high tack transfer such as R-tapes high tack?

  6. Hi Scott. If you're sending it out to be installed by the customer, you wouldn't heat it beforehand. But, if you're using a standard, high tack paper tape, your customer may have to. That's one reason we're so happy about the new Main Tape Preview Plus GXF101.
    It's a high tack clear tape that works much better, making the heating unnecessary. For more information, please refer to my September 28th blog post.

  7. Can I get a sample 24 width to try? I went to order some and it only comes in 24 x100 yards lengh. I really don't want to purchase that much until I can try it first as I was having trouble with my first run using Oracale 631 for interior applications. Not sure if it's the release tape (we used HT55 which is recommended by Oracal) or my printer, if she has the depth setting not correct. Oracal Rep said it might be the adhesive being cut into and the glue comes up into the cuts thus making some not come off the backing. For some of our tests (before we go live with our sight) some fo the vinyl stayed on the backing and some stuck with the release tape so we would like to try the Preview Plus. A sample if possible.

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