In the world of wood finishing, there are many options to choose from. Two popular options are shellac and polycrylic, each with its unique properties and use.
The question arises, can you use polycrylic over shellac? In this blog, we will explore the compatibility of these two finishes, their pros and cons, and what to consider when deciding which one to use for your project.
Whether you are a DIY enthusiast or a professional woodworker, understanding the differences between shellac and polycrylic will help you make an informed decision about the best finish for your project.
What is Shellac?
Shellac is a natural resin that is derived from the lac bug. It is collected from the trees that the lac bug feeds on and processed into a material that is used as a wood finish.
Shellac has been used for centuries in woodworking and is known for its excellent adhesion properties, fast drying time, and high gloss finish.
It is a versatile finish that can be used on a variety of surfaces, including wood, metal, and ceramics. Shellac is also a natural product and is considered environmentally friendly.
What is Polycrylic?
Polycrylic is a type of water-based polyurethane finish that is commonly used in woodworking and furniture making. Unlike traditional oil-based polyurethane finishes, Polycrylic is water-based and provides a clear, glossy finish that is easy to clean and maintain.
Polycrylic is known for its durability and resistance to moisture, heat, and chemicals. It is a popular choice for those who are looking for a finish that provides protection and enhances the natural beauty of the wood without yellowing over time.
Polycrylic is also a low-VOC (volatile organic compound) finish, making it a more environmentally friendly choice than traditional oil-based finishes. It is easy to apply and dries quickly, making it a great choice for projects where time is a factor.
Types of Shellac
There are several types of shellac available on the market, each with its own unique color and characteristics. Some of the most common types of shellac include:
- Blond Shellac: This type of shellac has a light yellow color and is often used as a sealer or primer. It provides a subtle color to the surface and is ideal for use in light-colored woods.
- Amber Shellac: This type of shellac has a warm yellow tone and is commonly used to finish light-colored woods. It provides a warm glow to the surface and enhances the natural beauty of the wood.
- Garnet Shellac: This type of shellac has a reddish tint and is typically used to finish darker woods. It provides a rich, warm tone to the surface and can bring out the natural grain patterns of the wood.
- Orange Shellac: This type of shellac has an orange color and is ideal for use in medium-colored woods. It provides a warm, rich color to the surface and can help to enhance the natural beauty of the wood.
- Dark Brown Shellac: This type of shellac has a dark brown color and is ideal for use in dark-colored woods. It provides a rich, deep color to the surface and can help to enhance the natural beauty of the wood.
Types of Polycrylic
- Clear Polycrylic: This type of Polycrylic provides a clear, glossy finish that enhances the natural beauty of the wood without adding any color.
- Satin Polycrylic: This type of Polycrylic provides a satin finish that is less glossy than the clear finish. It is ideal for those who want a subtle sheen that is not too glossy.
- Matte Polycrylic: This type of Polycrylic provides a matte finish that is ideal for those who want a low-gloss finish. It is a great choice for surfaces that will be frequently handled, as it provides a non-slip surface.
- Semi-Gloss Polycrylic: This type of Polycrylic provides a semi-gloss finish that is a compromise between the high gloss of the clear finish and the low gloss of the satin finish.
Pros and Cons of Using Shellac
Pros
- Fast Drying Time: Shellac dries very quickly, making it a popular choice for projects where time is a factor.
- High Gloss Finish: Shellac provides a high gloss finish that can enhance the natural beauty of the wood.
- Excellent Adhesion: Shellac has excellent adhesion properties, making it a great choice for surfaces that are prone to peeling or chipping.
- Versatile: Shellac can be used on a variety of surfaces, including wood, metal, and ceramics.
- Environmentally Friendly: Shellac is a natural product and is considered environmentally friendly, making it a great choice for those who are concerned about its impact on the environment.
Cons
- Sensitivity to Heat and Moisture: Shellac can be sensitive to heat and moisture, and may not be a suitable choice for surfaces that will be exposed to these elements.
- Limited Color Options: Shellac is available in a limited range of colors, so if you are looking for a specific color, it may not be available.
- Requires Multiple Coats: In order to achieve a smooth, even finish, multiple coats of shellac may be required.
- Can be Difficult to Repair: If shellac is damaged, it can be difficult to repair, and the entire surface may need to be stripped and refinished.
Pros and Cons of Using Polycrylic
Pros
- Water-Based: Polycrylic is water-based, making it a more environmentally friendly choice than traditional oil-based finishes.
- Easy to Clean and Maintain: Polycrylic is easy to clean and maintain, making it a great choice for surfaces that will be frequently handled.
- Durable: Polycrylic is known for its durability and resistance to moisture, heat, and chemicals.
- Fast Drying Time: Polycrylic dries quickly, making it a great choice for projects where time is a factor.
- Versatile: Polycrylic is available in a range of finishes, including clear, satin, matte, and semi-gloss, making it a versatile choice for a wide range of projects.
Cons
- May Yellow Over Time: Polycrylic may yellow over time, particularly when exposed to UV light.
- Can Be Difficult to Repair: If Polycrylic is damaged, it can be difficult to repair, and the entire surface may need to be stripped and refinished.
- May Require Multiple Coats: In order to achieve a smooth, even finish, multiple coats of Polycrylic may be required.
Importance of Using Dewaxed Shellac
- Improved Adhesion: Dewaxed shellac provides a better surface for Polycrylic to adhere to, which can lead to improved durability and longevity of the finish.
- Reduced Risk of Finishing Issues: Using dewaxed shellac eliminates the risk of Polycrylic not adhering properly or peeling off, as the wax in shellac can prevent proper adhesion.
- Consistent Finish: Using dewaxed shellac ensures a consistent finish, as the absence of wax in the shellac reduces the risk of finish imperfections.
- Better Protection: Dewaxed shellac provides better protection for the wood, as it forms a more solid and durable base for the Polycrylic finish.
Using dewaxed shellac is important when applying Polycrylic over shellac, as it provides a better surface for adhesion, reduces the risk of finishing issues, ensures a consistent finish, and provides better protection for the wood.
Tips for Testing Polycrylic Over Shellac
- Test a Small Area First: Before applying Polycrylic over a larger surface, it is recommended to test a small area to ensure compatibility and to check for any potential issues.
- Clean the Surface: Clean the surface of the shellac thoroughly to ensure that it is free of dirt, dust, or oils that could prevent the Polycrylic from adhering properly.
- Sand the Surface: Lightly sand the surface of the shellac to remove any imperfections and to provide a smooth surface for the Polycrylic to adhere to.
- Apply a Thin Coat: Apply a thin, even coat of Polycrylic to the test area and allow it to dry completely before inspecting it.
- Inspect the Test Area: Inspect the test area to check for any issues, such as adhesion problems or finish imperfections. If the test area is successful, proceed with applying Polycrylic to the rest of the surface.
Testing Polycrylic over shellac is important to ensure compatibility and avoid potential issues. By testing a small area, cleaning the surface, sanding the surface, applying a thin coat, and inspecting the test area, you can ensure a successful application of Polycrylic over shellac.
Comparison of Polycrylic and Shellac
| Feature | Polycrylic | Shellac |
|---|---|---|
| Type of Finish | Water-Based | Solvent-Based |
| Durability | Good | Good |
| Drying Time | Fast | Fast |
| Availability of Finishes | Clear, Satin, Matte, Semi-Gloss | Clear, Amber, Orange, Dark |
| Compatibility with Other Finishes | Good | Good |
| Environmental Impact | Low | Moderate |
| Maintenance | Easy | Easy |
| Cost | Moderate | Moderate |
FAQs
Yes, polycrylic can be used over painted surfaces as long as the paint is completely dry and free of dust and oils.
Typically, two coats of polycrylic are recommended for a durable and smooth finish.
Yes, polycrylic can be lightly sanded after it dries to remove any dust nibs or to smooth out any drips.
Polycrylic can yellow over time, especially if exposed to direct sunlight. To minimize yellowing, it is recommended to use a water-based polycrylic or one that is labeled “ultra-clear.”
Typically, you should wait 2-3 hours between coats of polycrylic. However, it is best to refer to the manufacturer’s instructions for specific drying times.
Conclusion
Using polycrylic over shellac is technically possible, but there are a few considerations to keep in mind. It’s important to properly prepare the surface of the shellac by scuffing and cleaning it, and using a water-based polycrylic will help ensure a smooth and even application.
While polycrylic provides a durable finish that is resistant to water damage, it is also important to note that most polycrylic is self-sealing, meaning that another layer of product cannot be applied over it. If you are looking for a hard and resistant finish, polycrylic is a good option.
However, if you need to reapply a different finish or product in the future, you may want to consider using lacquer instead. Ultimately, the choice between polycrylic and shellac will depend on your specific project requirements and the final look you want to achieve.
