Want to refinish your old workpieces and wondering if you can use polyurethane over a lacquer finish?
Yes, you can use polyurethane over lacquer, but the finish might not be long-lasting. Both finishes are chemically incompatible with each other and can result in cracking and peeling of the polyurethane. However, you can add a neutral coat of shellac or sand the lacquer finish to improve the adhesion.
We tested it out by applying polyurethane over lacquer and share our insights here.
Polyurethane and lacquer are popular finishes for wood surfaces, but they have different properties and solvents.
Many people wonder whether it’s possible to put polyurethane over lacquer, and the answer is yes, it is possible.
However, it’s important to understand the compatibility of the two finishes and to properly prepare the surface before applying polyurethane.
While it’s not always recommended to apply polyurethane over lacquer, it can be done in some cases.
The two finishes can create a chemical reaction and cause issues such as poor adhesion, cracking, peeling, or other defects in the finish.
Therefore, it’s important to consider the condition of the surface and the need for proper preparation before applying polyurethane over lacquer.
Do a small test first to see if polyurethane and lacquer are compatible.
Clean (using lacquer thinner or mineral spirits) and dry the surface, then apply some polyurethane and let it dry.
Check if it sticks well and looks good. If yes, you can use polyurethane over lacquer. If no, choose another finish.
Before using polyurethane, clean the lacquer surface well.
The surface should be completely free from dirt, dust, or debris to ensure that the polyurethane adheres properly and provides a smooth finish.
Use a soap and water solution or a stronger cleaner if needed.
Wipe the surface with a cloth or sponge and rinse with water. Let it dry completely without heat.
Sand the lacquer surface lightly with fine sandpaper to make it smooth and ready for polyurethane.
To sand the surface, use fine-grit sandpaper such as 220-grit.
Sand the surface lightly in a circular motion, being careful not to sand through the protective lacquer layer and damage the wooden surface.
After sanding the surface, wipe it clean with a soft cloth to remove any dust or debris.
You can also use a vacuum cleaner or a tack cloth to ensure the surface is completely clean.
If there are any big scratches, use coarser sandpaper to fix them.
After checking the compatibility, cleaning, and sanding the surface, it’s time to apply the polyurethane.
Use a brush, roller, or spray gun to apply polyurethane over lacquer.
Generally, a brush is recommended, but you can also use a roller to apply polyurethane over larger workpieces at the cost of the surface finish.
Similarly, you can spray polyurethane to cover a large work area in less time, enhancing productivity.
Stir the polyurethane gently and apply it in thin coats.
Avoid shaking the can, as this can create bubbles and affect the final finish.
You can also use wipe-on polyurethane to apply PU with a rag to ensure thin, uniform coats on hard-to-reach areas.
Sand the surface lightly with fine sandpaper after each coat of polyurethane dries. Wipe away any dust with a cloth or vacuum.
Apply the next coat of polyurethane the same way. Repeat until you get the finish you want.
Let the final coat of polyurethane dry and cure fully before using the surface. This can take hours or days, depending on the weather.
Don’t use or wet the surface until it’s fully cured. Take care of the finish to make it last longer.
Use polyurethane over lacquer when:
While it is possible to apply polyurethane over lacquer, it is best to stick to one type of finish when refinishing or repairing a surface to avoid compatibility issues.
Products from different manufacturers often have different formulations, so test them before applying them to the actual workpiece.
Also, it is important to identify the type of lacquer on your workpiece and use the compatible type of polyurethane (water-based or oil-based) accordingly.
Yes, you can apply lacquer over tung oil to enhance its durability and finish. However, it is important to allow the tung oil finish to cure completely before applying lacquer.
No, lacquer finishes are not inherently water-resistant. Exposure to water can cause a lacquer finish to soften, blister, and peel. To increase the water resistance of a lacquer finish, you can apply a clear topcoat such as polyurethane or a water-resistant lacquer.
Yes, you can apply lacquer over polyurethane, but both finishes have compatibility issues and can result in poor adhesion and peeling.
