Application Fluid: Guidelines for Use

What is Application Fluid? Why do some sign-makers say you should never use it? When should you use it, and when should you avoid it? What's the best way to use it without causing unwanted complications? Does the kind of vinyl matter? Does the kind of app tape matter? These are just a few of the many frequently asked questions we hear from customers about application fluid. The answers to these questions and more are below in our basic guide to application fluid.

The What, When, Why & How of Application Fluid

What is application fluid and how does it work ?

Application fluid is a product designed to help apply vinyl graphics with precise placement. Normally, when you apply a pre-masked vinyl graphic to a substrate, you remove the release liner, then position the vinyl on the substrate. This positioning is the tricky part. If you're applying vinyl to a fixed-position substrate like a vehicle door or storefront window, the letters must be placed precisely. This can be done with careful measuring and a hinge method. Or, you can move the vinyl around until it's just right. Of course you can't re-position the vinyl in this way with the adhesive touching the dry substrate. That's where application fluid comes in. Application fluid provides a temporary lubricant that allows you to move the vinyl around or pick it up and repeatedly re-position it until you get that Goldilocks moment and it's just right.

Now that you know what it's for, you might ask how it works.

Most application fluid comes in gallon and quart bottles with a sprayer for the quarts. You simply spay a fine mist on the substrate and/or the back of the pre-masked vinyl and tape. This is done of course after you remove the release liner. Then you place the vinyl in the general area you want, and move it into place. Then use a squeegee and some paper towels to force the fluid out from under the vinyl and soak it up. Once you've squeegee'd all of the fluid out from under the tape and vinyl, you can begin to remove the tape and finish the application. Depending on the kind of tape, the kind of vinyl, and the amount of fluid used, it may take a while before you can remove the tape and finish the job.

Why use it and when?

As noted above, the most common reason for using application fluid is to get precise placement of an applied graphic. It gives installers some 'wiggle room' or a 'fudge factor'. The most common uses for wet applications are vinyl graphics on vehicle doors and windows, large banners, and storefront window graphics. But you can also use it for simple things like cor-plastic yard signs and real estate signs. Those who prefer dry application generally achieve proper placement by the old adage, measure twice cut once. Or, in this case, measure twice, stick once. A good dry application can be done on most of these same substrates using a hinge method. The advantage of the hinge method is that the vinyl's position on the substrate is verified before the release liner is removed exposing the adhesive. First you place it, then you stick it. Hinges are also useful in applying very large graphics like vehicle wraps in which squeegeeing adhesive fluid out from under the vinyl is simply not feasible. There are several examples of hinge method installations in our Basic Vinyl Application Guide, and a little more about hinges and transfer tape for digitally printed vinyl graphics here.

Why not use a drop or two of soap mixed with water?

If you are going to use application fluid, why not just make your own? Some people do by diluting dish washing detergent. That's an economical approach, but not a good one. Dish washing detergents are not designed for use with vinyl graphics so there may be chemicals in the detergents that can degrade the adhesive and cause your applied graphics to fail. If you do decide on wet application, do yourself and your customers a favor, and use fluids like SureGlide, RapidTac, Rapid Tac II, or Splash. All of these products are formulated specifically for use with sign industry vinyl.

How to Do Wet Right

What are the guidelines for applying wet application successfully? There are really only a few basic tips to remember. Use the fluid properly and be mindful that the kinds of vinyl and tape used to affect your workflow.

Quickly and Sparingly

The basic rule of thumb for successful wet application is to use the fluid sparingly and quickly. Using too much fluid or leaving it on the substrate too long can retard vinyl adhesion, and cause severe problems with the application tape. Don't flood the substrate! Spray a fine mist on the tacky bottom of the vinyl after removing the release liner. Spread it around with your fingers to get a thin, evenly applied coat of fluid. If you prefer, you can also wet the substrate, but do it the same way; a fine mist spread with your fingers to assure a thin, even coat.

No puddles! When you place the graphic on the substrate, you should feel a little tack, but you should be able to easily lift and reposition the graphic. If you're swimming the vinyl across a wave of application fluid, you've overdone it. As soon as you have the graphic positioned where you want it, begin forcing the fluid out from under the masked vinyl with your squeegee and soak it up with paper towels. You'll find that you have to squeegee the entire graphic several times before all the fluid is expelled. Be thorough, but be efficient. This should be done quickly because leaving excess fluid under the vinyl and tape can cause the tape to de-laminate. The adhesive layer will detach from the face film and remain on the vinyl in a gooey residue. It's gross and annoying.

Vinyl & Substrate Variables.

Pay attention to the type of vinyls and substrates you're using. Some work better with fluid than others. Sign industry vinyl films are made with either acrylic or solvent based adhesives (acrylic is sometimes referred to as "emulsion". You can learn more about that here). Because acrylic adhesives are water-based, they weaken more when exposed to application fluid.

If you're doing a wet application with an acrylic adhesive vinyl, you should be prepared to wait a while before removing the transfer tape. The adhesive won't 'wet out' or bond with the substrate as quickly as usual. It may take 30 minutes or more for the vinyl to set before the tape can be removed. It will take another day or two for the adhesive bond to become permanent, so advise your customer to treat the applied graphic gently for the first few days.

Vinyls with solvent adhesives will wet out more quickly but should also be given a few extra minutes before the tape is removed. Rough substrates already challenge the bond between vinyl and substrate. Never use application fluid to apply vinyl to a rough or textured substrate (i.e. wall graphics with 'knockdown' or bumpy texture). It may take hours before you're able to remove the tape and finish the application.

App Fluid Combinations to avoid

• Reflective and Metalized films: Reflective vinyl should always, always be applied dry. Use of application fluid with reflective vinyl is sure to cause the graphic to fail. Likewise, metalized films like chrome and holographic vinyls should almost always be applied dry. The foil layers used in the construction of these films can be easily corroded by exposure to fluid. Wet applications tend to cause extreme failure in the form of visible corrosion that makes silver films blacken like tarnished silverware. There is one exception to this rule. RapidTac II is especially formulated to work with metalized films and can be used with most metalized PVC and polyester vinyls without corroding the foil layer.
• Clear App Tape: Paper tape has a porous face film that allows the fluid to pass through so it can be driven out from under the tape with pressure and soaked up with a paper towel. Not so with clear tape. Clear transfer tapes have plastic face films that trap application fluids under the tape. As noted above, trapped application fluid can delaminate the adhesive. If you're doing a wet app with clear tape and the adhesive stays behind when you remove the tape, it's probably because you used too much fluid or left it there too long.
• Cleaning Agents: Don't use Windex or other cleaning agents before wet application. Sign industry application fluids like SureGlide and RapidTac contain cleaning agents that are compatible with the vinyl. Other cleaners may contain chemicals incompatible with the vinyl adhesive or app fluid producing unexpected problems. Use your application fluid to clean the substrate before applying the vinyl.
• High tack vinyl and acrylic adhesive films: As noted above, application fluid weakens acrylic adhesives more than solvents. The weakening of the vinyl's adhesive makes it harder to remove the tape without pulling the vinyl off the substrate. High tack transfer tape exacerbates this problem by pulling even harder on the weakened vinyl. Our test samples were applied using high tack paper tape on MACtac 8900, an indoor vinyl with an acrylic adhesive (Fig 1). It took over 40 minutes before we were able to remove the tape without pulling the vinyl from the cor-plastic sign blank. Most of that delay was due to the fluid weakening the adhesive, but a medium tack tape would get it done more quickly by putting less stress on the vinyl's adhesive.
• Tape tip: If you must use high tack paper tape, (or if you just want to speed up the process), wet the back of the application tape with your app fluid of choice before removing the tape. The fluid will permeate the paper tape's face film and soften its adhesive making it easier to remove the tape without pulling up the vinyl. This tip can also be used in dry applications to prevent bubbles caused by stressing the vinyl when removing a high tack transfer tape. Due to their plastic face films, this tip doesn't work with clear tape.

Whether you apply vinyl graphics dry or wet is largely a matter of personal preference. But if you do decide to use wet application, these simple tips will help you avoid some common pitfalls and get the maximum benefit from this useful vinyl installation tool. 

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