PSA Veneer Application Instructions and FAQ
Some helpful information about "peel and stick" veneer.

Application Instructions
The steps below will help you get the best possible bond on your veneer panel. Work carefully and take your time. Feel free to contact us if you have any questions. We are here to help make your project a success!

Acclimate the Veneer and Project Surface
PSA veneer and the substrate surface must be acclimated before use. Place the veneer between two sheets of plywood, MDF, particle board or similar flat surfaces. The veneer will gradually flatten out completely. It may be necessary to place some weight on top of the sheets. Let it acclimate to your shop's environment this way for no less than 72 hours. Some sources indicate that acclimating for five days is ideal. It is also important that your shop humidity is approximately 40% relative humidity. Higher or lower RH could result in the veneer developing an irreversible buckle. It is also recommended that the work area temperature is kept between 65° and 85° F.

Make a Test Panel
Avoid jumping right into the main veneer project. Instead, follow the instructions below with a test piece of PSA veneer and some scrap material from the project surface. You'll be glad you did this because there is a short learning curve to using this kind of veneer. Proceed to the main project only if you are satisfied with the performance of the test panel.

Getting Started

1. The best way to prepare the project surface begins with a light sanding using 150-180 grit sand paper. Do this only if you are certain that sanding will not create hazardous dust. PSA veneer is not suitable for use on bending plywood or any non-rigid substrate.
    
   
2. Use a clean cloth to wipe the project surface with denatured alcohol. This will remove many surface contaminants that can prevent the PSA from adhering. The surface should be free of dust when this is complete.
    
   
3. It is often a good idea to coat porous substrates with shellac or oil-based polyurethane. When dry, sand the surface lightly using 180-220 grit paper. Test with scrap to see if a coating like this is suitable for the project surface. You may find that a coating makes a huge difference in bond strength on porous surfaces.
    
   
4. Cut the veneer to the approximate size of the project surface. Allowing some extra width and length give you room for error when the veneer is set onto the project. The ideal amount of extra material will depend on the size and complexity of the panel as well as your precision when applying the veneer. Keep in mind that PSA adhesives bond instantly on contact.
    
   
5. Small Projects:
   Remove the protective film from the back of the PSA layer and carefully set the veneer onto the project surface. Smooth out the veneer using finger pressure and going along the grain (never across it).
    
   
6. Medium to Large Projects:
   Remove a few inches of the protective film on the back of the PSA veneer. Then carefully align this exposed tacky section of the veneer and with the edge(s) of the project surface. If possible, allow a bit of overhang. Many users will find it helpful to have an extra person who can hold one end of the veneer up and off the project surface as the other person carefully peels back more of the protective film and then sets that area of veneer onto the project surface using hand pressure to smoothly press the veneer into position. Continue removing the protective film and setting the veneer down as you work toward your helper. It is very important to avoid pockets of air between the project surface and the veneer so work slowly and methodically.
    
   
7. Use a veneer scraper to set the bond as described in the section below. Always scrape along the grain, and never across it. No additional clamping is necessary after the scraping process is completed.
    
   
8. Most users find that a fresh razor knife is the best tool for trimming excess veneer from the edges of the panel. Final clean up of the edge can be done with light sanding.
    
   
9. Allow 24 hours before applying a stain/finish. Water-based stains and finishes can cause wood cells to expand so always apply the first coats lightly. Flooding the surface with a heavy water-based stain/finish can results in bubbles forming on the surface.

Setting the Bond
PSA veneers require a veneer scraper to set the adhesive and permanently bond the veneer to the project surface. As indicated by the name, this type of adhesive is sensitive to pressure. The most durable level of adhesion is achieved when a maximum amount of pressure is used to set the bond. More pressure equals more strength.

Don't make the mistake of using a roller to set the bond. It simply will not work since it doesn't concentrate pressure evenly. A veneer scraper doesn't look like much but it works wonders. The scraper tool uses a simple but powerful concept in which the leverage of hand and arm force focuses pressure at the tip of the tool to create a durable bond. It almost guarantees a perfect bond when used correctly.

To achieve maximum bond strength, be sure to scrape the entire surface of the veneer using the centerline technique shown below. Most PSA veneer manufacturers recommend scraping the surface twice. Always scrape along the grain! Never scrape across the grain as this will stretch the veneer and lead to ripples and buckling.

Begin at the center of the veneer and work toward the edges in the sequence shown below. This method will prevent bubbles in the veneer and create an excellent bond. Start in the center and while firmly pressing downward, pull the scraper tool in the direction of the arrows shown below. Be sure to pull the scraper over each inch of the veneer to get the best possible bond.

Frequently Asked Questions About PSA Veneer

What is PSA veneer?
Pressure sensitive adhesive (PSA) is a glue layer added to the back of paper-backed veneer. It comes with a protective backing that the user removes when applying it to the project surface. A liquid glue is not needed because the PSA layer is the adhesive. Though a bit expensive, it is perhaps the easiest way to apply veneer and it can be used on a variety of project surfaces.

To what surfaces can I apply a PSA veneer?
PSA veneer bonds to most smooth surfaces that are dry and free of dust and contaminants. We have seen success with PSA veneer used on laquered, varnished, painted, and powder-coated surfaces provided that these coatings were in good condition. PSA also bonds to plywood, MDF, particle board, and some metal surfaces such as aluminum. PSA veneer is not suitable for substrates made from bending plywood (also known as "wiggle wood") or any other non-rigid surface.

Who makes the PSA layer?
Like most suppliers, our PSA is 3M's #9505. We have been offering it for more than 15 years on our paper-backed veneers and it works well for the majority of our customers. It is an excellent adhesive for many projects such as custom speakers and basic furniture projects.

Can the veneer be repositioned if accidently set incorrectly?
Generally speaking, it is almost impossible to lift and reposition a PSA veneer once it is applied. Any hope of repositioning depends on the project surface and the size of the area that is in contact with the veneer.

Will the scraper tool scratch my veneer?
The scraper tool will not damage the veneer surface if used correctly. The "blade" on our veneer scraper is made from high density polyethylene. This is a low-friction plastic that glides across the surface without marring the wood.

Can I use a roller instead?
A handheld roller is not suitable for applying PSA veneer. It simply does not concentrate enough pressure over the contact surface to create a durable bond. A veneer scraper is a must!

Can I make my own veneer scraper?
A wide block of softwood like pine can typically be used as a scraper. Lightly round-over the long grain side of a block of pine and use that edge as a scraper. Don't use the end grain side as this could damage the veneer surface.

Should I apply a coat of contact cement first if I am using a PSA veneer?
No. Doing so would be a very bad choice. The PSA layer can be affected by the polymers and solvents in contact cement.

How do I test my veneer to make sure it is bonded properly?
Since there are many combinations of veneer, substrates, adhesives, finishes, and environmental conditions, we highly recommend testing a small piece of veneer with your application and finishing process before you begin the main veneer work. Keep in mind that maximum adhesion occurs approximately 48 hours after the veneer is applied.

Be certain to check for bubbles before applying your finish. If bubbles are present, this may be the only time to address these issues. The best way to check for bubbles is to place a strong work light beside the veneered panel and no more than 15 degrees above it. Look for peaks and shadows across the panel.

How can bubbles be removed from the veneer surface?
Most bubbles can be easily repaired with additional scraping - along the grain, not across it. Another option is to place a piece of cotton or flannel cloth over the bubble and gently heat the bubble with a clothes iron. Keep the iron in motion to prevent overheating the veneer. Once the veneer is lightly heated, scrape the bubble again until the area cools down.

Does the substrate have to be stripped of any surface coatings before the PSA veneer is applied?
PSA veneer can be applied over a smooth painted or lacquered surface if that coating is durably bonded to the substrate. The veneer application will only be as durable as the coating under it.

How do I stain and finish a veneered project?
Since it is a real wood product, veneer stains just like solid lumber. However, many users find that they get a more even stain color if they sand the veneer one grit grade higher than the rest the project. If the solid wood part of a project was sanded with 150 grit sandpaper, then consider sanding the veneered parts with 180 grit to get optimum color matching.

It is best to apply a protective finish to the veneer when the ambient humidity is 55% or less. Do not use heavy coats of finish. Instead build up multiple smaller coats which dry faster and trap less solvent under the finish. Additionally, most catalyzed finishes will "check" or crack if applied too thick.

Can the veneer be stained and finished before I applying to the project surface?
Generally speaking it is not ideal to pre-stain a veneer for because the process of applying a paper-backed veneer with PSA requires the use of a scraper tool which can smear, mar, or scratch the finish.

Can I buy just the PSA layer?
No. The adhesive layer would be very hard or perhaps impossible to apply without machinery dedicated to performing the application task.

Why does my veneer not have the PSA applied all the way to the edge of the sheet?
The PSA film used on a 4x8 veneer sheet is 48" wide. However, the veneer is typically over-sized an inch or so in width because the factory process of applying the PSA film is imperfect. It is a challenge to line up the PSA film with the exact edge of the veneer, so the factory will often over-size the veneer sheet by up to an inch. You simply have to trim those edges off, but you still end up with 48" of width on a 4x8 veneer.

Does the PSA layer on the veneer have a shelf life?
It seems odd, but yes. The manufacturer states in their product literature that the shelf life is 12 months.