Identifying a good finish for wood is essential to any woodworking endeavor. Whether you are a hobbyist or a professional woodworker, you will have to choose a suitable finish at some point to protect your wood or improve its aesthetics.
Among the most popular wood finishes are shellac and polyurethane. So you may want to know how the two compare.
This article compares shellac vs polyurethane side by side to help make it easier for you to identify which product may suit your next project better.
What is Shellac?
Shellac is a wood finish made from resins secreted by female lac bugs on certain trees. The shellac used as a wood finish is a commercially viable variety resulting after processing and dissolving dry flakes of the product in a solvent such as alcohol.
Shellac naturally dries quickly and can work as a wood sealer or finish. When using shellac on wood, you can apply multiple coats and complete the projects within the same day due to the fast-drying property.
Shellac pros and cons
Like any wood finish, shellac has its share of strengths and limitations.
- The product adds a warm amber tone that can enhance the wood’s natural grain and beauty.
- You can have it in a high-gloss finish
- Retains its color for long
- Shellac dries very quickly
- Shellac is not as durable as polyurethane or varnish; water and alcohol can dissolve it off the wood surface.
- The product has a very limited shelf-life; it needs to be used within six weeks of mixing it with alcohol.
What is Polyurethane?
Polyurethane wood finish is a synthetic resin available in liquid form but with varying thicknesses from one product to the other. It is available in both water and oil-based varieties and dries to form a tough film on wood or other surfaces where it is applied.
Due to its strength, the product works perfectly on a wide range of surfaces, including cabinets, furniture, floors, doors, countertops, windows, etc.
Pros and cons of polyurethane
Like shellac, polyurethane has strengths and limitations. This section looks at both sides of the coin.
- Both water-based and oil-based polyurethanes are long-lasting and highly durable.
- Forms a hard-wearing film protecting surfaces against abrasion, water, and moisture damage.
- Polyurethane offers better resistance to heat and chemicals, making it ideal for kitchen applications like furniture.
- Poly is available in clear versions that help wood retain its natural color.
- Polyurethane can take longer to dry than shellac.
- Some polyurethane types turn amber over time due to UV exposure.
What is the difference between shellac and polyurethane?
The difference between shellac and polyurethane is that Shellac is a quick-drying natural resin secreted by the female lac bug and adds a warm tone to wood. Polyurethane wood finish is an artificial resin available in both oil and water-based forms. Shellac dries in 30 minutes while polyurethane takes 2-6 hours to dry.
Shellac Vs Polyurethane Side by Side
Here is a detailed look at both products for a more straightforward comparison.
Polyurethane vs shellac: Common uses
Shellac has a wide range of cosmetics, food coatings, and dentistry uses. However, we focus on its use as a popular wood finish in this case.
You can use the product as a primer or sealant for wood, glossy varnish, and wood stain. It does an excellent job of blocking tannins as a wood sealant or primer.
When used in fine furniture or other wooden items, shellac is often applied as a protective topcoat, albeit less durable than other varnishes and polyurethane.
On the other hand, polyurethane is used as a protective topcoat for furniture, wooden floors, trims, countertops, cabinets, decking, and several other wooden surfaces indoors and outdoors.
However, water-based polyurethanes are commonly used in indoor applications, while oil-based varieties are more commonly used in exterior applications.
Shellac or Polyurethane: Colors
Shellac is naturally available in various warm shades. The common shellac colors include medium brown, yellow, blonde, gold, amber, and orange.
In contrast, polyurethane has no distinct natural color. The product usually comes in clear form, but the oil-based versions can leave an amber tint on wood due to its solvents.
Wood surfaces coated with most polyurethanes may also turn yellowing over time due to sun exposure. This yellowing is more common with oil or solvent-based polyurethanes.
Polyurethane vs Shellac: Sheen levels
Shellac usually creates a high-gloss or semi-gloss sheen with a beautiful tint.
On the other hand, polyurethane surfaces have various sheen levels, including lustrous, mid-gloss, satin, and matte. You can choose the sheen level that best matches your project goals with polyurethane.
Shellac vs Polyurethane: Ease of application
Both shellac and polyurethane offer a wide range of options regarding application methods. For example, when working with shellac, you can apply it to your project with a lint-free cloth, paintbrush, or spray can.
The surface should be dry and ready for a second coat in half an hour or one hour. Ensure you scuff sand between coats of shellac to create a smooth, even surface.
Polyurethane is also applied with a cloth, paintbrush, foam brush, or sprayer. Like shellac, you must sand the surface before applying polyurethane to achieve the best results.
However, ensure you use a synthetic-bristled brush when working with water-based poly and a natural bristled brush for oil-based polyurethane.
Both shellac and polyurethane typically require about three coats for the desired coverage. Additionally, you need to work within the wood grain for most products.
Related post: How to Remove Shellac from Wood
Polyurethane vs. Shellac: Drying time
Shellac takes about 30 minutes to one hour to dry and be ready for recoating. That’s a relatively quick drying time so that you can apply around three coats in less than six hours.
The drying time will depend on whether the product is water-based or oil-based with polyurethane.
Water-based poly dries relatively quickly, albeit slower than shellac. On the other hand, oil or solvent-based polyurethanes tend to take more time to dry.
You can often expect water-based polyurethane to dry completely in about two hours, so you can recoat in three to four hours.
However, oil-based poly undergoes a chemical reaction when curing and will take 24 hours or longer to complete drying. Therefore, a project involving oil-based poly can stretch across several days.
Which is better, polyurethane or shellac?
Both shellac and polyurethane have their strengths, but polyurethane tends to offer more durability, making it a relatively better wood finish. It also goes on clear, helping you preserve the natural color of your wood, which can be perfect if you prefer the wood’s color. Water-based poly and shellac dry relatively quickly and do not hold up well to household chemicals and heat. Nonetheless, polyurethane is still much more durable than shellac.
What is shellac good for?
Shellac is an excellent natural primer that forms a strong undercoat for other wood finishes. It also works great as a wood sealant that blocks tannins and unpleasant odor. As a topcoat, you can use it as a wood stain due to its natural shades or apply it as a lustrous wood finish.
What is the difference between polyurethane, shellac, and lacquer?
- The main difference between polyurethane, shellac, and lacquer is that polyurethane is a synthetic resin or liquid plastic available in solvent or oil-based and water-based formulations.
- Shellac is a natural tinted product with numerous uses in cosmetics, food coatings, and woodwork, where it is used as a primer, sealer, and lustrous topcoat.
- Lacquer is a crystal-clear wood finish made of shellac mixed with alcohol that forms a glossy, tough protective coat on wood, metal, and other surfaces.
- While lacquer is a product of shellac, the two wood finishes differ because lacquer shellac is crystal-clear and can consist of synthetic ingredients.
Is shellac good for waterproofing?
Shellac is highly resistant to water, but it is not waterproof. It is not ideal for waterproofing applications as it will only withstand water for approximately four hours, after which the surface may sustain some water-related damage. Find out whether polyurethane is waterproof in this article.
Is shellac water-based?
Shellac is not water-based. It’s an alcohol-based solution. Shellac is made from the resin of the lac beetle, which is native to Indian and Southeast Asian forests. The insect secretes a hard, protective covering over its body to ward off predators and protect itself from the elements. This covering is what we know as shellac.
Should you use shellac or polyurethane for kitchen cabinets?
Shellac is better for kitchen cabinets compared to polyurethane, so if you want an eco-friendly kitchen you can use it. The product makes your kitchen cabinets water-resistant and gives them an umber-tinted finish. Shellac is also great for coating and sealing old finishes plus you can easily repair it from chips.
What does shellac do?
Shellac brings out the natural grain and enhances the inherent beauty of wood if you apply it. It can be used on both unfinished and finished surfaces and provides a durable finish that resists scratches and stains. So far it’s among the best wood finish options now for centuries.
Shellac Vs Polyurethane: Final Thoughts
Finding an appropriate wood finish for any interior or exterior project can be challenging, especially due to the numerous options available on the market. As a result, you will often need to do some homework to weed out what is less suitable for your needs.
Thankfully, researching is what we do best, and we are happy to compile this kind of guide to make your life easier. We hope this detailed comparison helps you find the best finish for your next woodworking project.