Woodworkers may find it challenging to choose the right finish to use, especially if they are just starting to paint. This is because several finishes have different qualities and pros and cons for each. What’s the Difference Between Polyurethane, Varnish, Shellac, and Lacquer? This is a common question most people ask before choosing the right finish. There are lots of differences among these finishes. The differences vary based on the similar characteristics they feature.
I did some research, and here’s what I’ve found:
Varnish Vs. Polyurethane Vs. Lacquer Vs. Shellac: What’s The Difference?
They differ in drying and curing times, durability, and application methods. Polyurethanes are water- or oil-based synthetic plastic resins commonly used in interiors such as hard floors. While varnish is made of resin, oil, and solvent, it is designed for outdoor projects. Lacquer is stronger and more wear-resistant than Shellac and varnish.
But that’s just a brief snapshot, and there’s a lot more to know.
We will carefully look at the Difference Between Polyurethane, Varnish, Shellac, and Lacquer? Also, we will discuss other things such as the pros and cons of each finish, the advantage a finish has over the other, chat comparison, and lots more.
Let’s go.
Chart comparison
| Properties | Varnish | Polyurethane | Lacquer | Shellac |
|---|---|---|---|---|
| Curing | 24 days | 30 days | 2 weeks | 1 week |
| Fastest Drying | 30 minutes | 2 hours | 1 hour | 30 minutes |
| Colors & Tints | Can be tinted | color pigment | color varieties | aniline dye |
| Sheen | 30% | low sheen level | 40%-90% | 3%-5% |
| Durable & Lasting | durable | highly durable | highly durable | less durable |
| Toxicity | Toxic | irritating and toxic | dangerous | harmful |
| Budget | $13-$20 | $15-$20 | $20-$25 | $20-$25 |
| Application | Brush | Brush or roller | Bristle brush | Brush or pad |
| Clean Up | Mineral spirit | Water | mineral spirit | mineral spirit |
| Repair | steel wool | sanding and recoating | wet coat spray | 0000 steel wool |
Polyurethane
What is Polyurethane?
Polyurethane is a synthetic resin and a type of varnish used in finishing various surfaces such as woodwork, cabinets, or floors. It remains one of the best varnishes for painters due to its transparency, resistance to abrasion features, resistance to fungus, water, and mildew. It has a quick-drying feature when compared to other types of varnishes. Polyurethane can come in glossy or flat sheens.
Suppose you apply it as a varnish on surfaces. Water-based and oil-based Polyurethane improves your wood’s resistance level and other surfaces to household chemicals, water/moisture, abrasion, mar, heat, and scuff.
Polyurethane is readily available in two types: water-based poly and the oil-based or solvent-based Polyurethane. The water-based Polyurethane dries faster than the oil-based Polyurethane. At the same time, water-based Polyurethane is friendlier than oil-based Polyurethane.
Pros of Polyurethane
- It is durable
- It can stand the test of time
- Cost-effective
- The water-based Polyurethane dries faster
- Varieties of colors and tints
- Beautiful appearance
Cons of Polyurethane
- The oil-based Polyurethane takes longer to dry
- There’s a need to sand in-between coats
- Brushing as the most common application method
- makes the application process slow
How to Apply Polyurethane?
Applying Polyurethane depends largely on the type of poly you want to use. The way you’ll apply water-based poly will be different from that of oil-based. Let’s take a look at the procedures to follow to apple each of the two polyurethane types:
How to apply water-based Polyurethane
Supplies needed: synthetic fine bristle brush, cloth, or foam pad, tack cloth.
Steps:
- Start by roughing up the surface
- Applying a thin coat of water-based poly
- Allow the surface to dry
- Apply the second thin coat of poly
- Allow it to dry
- Repeat steps 2 & 3 and continue until you fine with the layers of poly
Usually, three layers of water-based poly may be enough if you work on lightly used surfaces. However, four to five poly coats will be ok if you’re working on wood projects. You won’t need to sand the surface before applying the poly solvent.
How to apply oil-based Polyurethane
Supplies needed: natural brush,
Steps:
- Sand the surface with fine 180-grit sandpaper
- Clean the surface to remove sanding dust
- Apply oil-based poly in thin layers
- Allow the surface to dry out completely
- Sand the surface with finer 320-grit sandpaper. Sand lightly
- Apply the second coat
- Repeat step 4, 5 & 6.
- Allow the project t dry
The best way to apply Polyurethane is with a foam or nylon brush. Applying a thin coat is always the best choice, leaving it to dry overnight before applying the second coat. Applying these coats usually takes about 3-4 coats. Polyurethane is always clear after you apply it. However, if you apply it in thick layers, it may provide a cloudy appearance.
Lacquer
What is Lacquer?
Lacquer is a finish most woodworkers prefer over other finishes. Thanks to its easy applications and quick-drying feature as a thinner finish. Lacquer provides users with a smooth and glossy look while offering durability on the surface as well. Moreover, it is highly resistant to damage due to its ability to penetrate the surface of the wood. It requires a high-volume and low-pressure sprayer when it is time to apply in a room with adequate ventilation.
Lacquer has three different variances: water-based, acrylic, and nitrocellulose lacquer. It is easier to repair when the need arises. Lacquer is commonly used on high-end furniture thanks to its thin texture and effective blending with previous coats.
Pros of Lacquer
- Hard curing and durable finish
- Impervious to water and other liquids
- As it ages, it doesn’t turn yellow or get cloudy
- There’s no need for extra care
- It has a super maintenance feature
Cons of Lacquer
- The application can sometimes be difficult (it requires equipment and a dedicated spraying area)
- It can produce toxic off-gassing during the first application (it is safe once it becomes dry)
- Removal of dents and scratches can be very difficult
How to Apply Lacquer?
Things to know when applying a lacquer finish
- Never use a brush-on finish
- Don’t over-brush the surface
- Be quick when brushing the surfacing
- Work in a well-ventilated workspace
- Choose either an airless sprayer or aerosol spray cans
- Add a thin coat at a time
- Use a high-quality natural bristle brush
You can apply Lacquer with either a brush or spray. However, it is not advisable to try brush and brush on a spray-on lacquer application. This is because the spray versions dry faster. Brush-on Lacquer also has a quick-drying time, but it is designed to provide at least a bit of time for application and even out the finish.
It is always advisable to use a bristle brush, preferably the one with high-quality natural bristles. Ensure you work quickly adding a thin coat. Also, avoid brushing too much the work. You can add extra coats later if you need to even out the finish.
However, if you are working with Lacquer and choose to spray over it, ensure you are not doing it in an enclosed room. Ensure there is available ventilation as much as possible. Lacquer has strong solvents and a strong odor, making it inflammable.
Steps to Apply Lacquer
- Prepare the wood surface by sealing wood cracks and holes suing lacquer-based filler. You can also use water-based filler
- Sand the surface with fine 180-grit sandpaper. Start with less fine grit sandpaper
- Clean the surface to remove sand dust
- Apply Lacquer using a brush. Spread the Lacquer while the move the brush back and forth
- Allow the surface the dry
- Sand the surface again but this time with 32-grit sandpaper
- Apply the second lacquer coat
Shellac
What is Shellac?
Shellac is a non-toxic wood finish that helps to improve the natural grain, adding smoothness to the surface of the wood. It has a warm-colored finish when it is applied to wood. Its color ranges from clear to garnet, making the wooden surface more attractive. It is also a film-forming finish that helps in protecting the wood surface.
Shellac is more effective as a sealant than a finish. By implication, Shellac comes as a water-resistant solvent that keeps your project protected from moisture. Besides, it prevents unpleasant and strong smells being released by the project. Shellac is easy to apply and works well on damaged faded pieces.
Pros of Shellac
- Has an easy application process
- Enhances the natural beauty of wood surfaces
- It has a quick-drying feature, enabling users to apply several coats in a day
- Doesn’t get discolored or spoilt by age
- Can be used and reused
- Adhere well to the surface
Cons of Shellac
- Only high gloss availability (users can dull it with 0000 steel wool)
- Alcohol can remove it
- It has lesser durability compared to other finishes but is not too difficult to repair
Application
Shellac is best applied on a wood surface. The denatured alcohol in this finish makes its evaporation process a very quick one, making several coats applicable in a day. You can use a brush, cloth, or even sprayer to apply it. After 30 to 60 minutes, you should sand the workpiece again for the second shellac coat application. If the outcome is far from your expectations, you may need to apply another coat to achieve the desired outcome.
How to Apply Shellac?
Things to know when applying Shellac:
- Flow shellac liberally onto the surface
- Apply Shellac in long, smooth strokes
- Tip off and spread the solvent along the grain of the wood
- You must sand between shellac coats
- Start application from dry to wet boundaries
- You don’t need to sand between shellac coats
- Start with a dry brush
- Keep the surface wet throughout as you apply Shellac
Steps to Apply Shellac:
- Sand the surface with a fine 320-grit sandpaper
- Remove the sanding dust and deposit and smoothen the surface
- Mix shellac solvent: Add 32 oz of shellac flakes to 4 liters of alcohol
- Pour the mixture into a clean can
- Dip your bristle brush into the container
- Spread the Shellac with the brush along the wood grain. Make sure strokes are smooth
- Wait for about 4 hours and allow the coat to dry
- Sand the surface with 400-grit sandpaper
- Clean the surface to remove sanding dust
- Buff out the final coat to remove the sheen with 0000 steel wool
Varnish
What is Varnish?
Varnish is a transparent, hard, and protective finish. It is used for the finishing of woods and other related materials. Traditionally, it combines drying oil, resin, or thinner solvent. The varnish finish is glossy. However, they may be designed for the production of satin or semi-gloss sheen with the addition of flatting agents. Varnish also comes in different types: natural resin, modified natural resin, and synthetic resin.
Pros of Varnish
- Natural enhancement of woods
- Protection from dirt, sunlight, and water
- Easy application
- Versatility
- Heat resistant
- Strength
Cons of Varnish
- It can become dull or yellowish over time when exposed to direct sunlight
- It requires utmost care when mixing to prevent bubbles
- There’s a need for mineral spirit or lacquer thinner to clean
How to Apply Varnish?
Things to know before applying varnish:
- During coating on varnish, ensure you have a light touch to work with.
- Also, make sure that you are bending only the tip of your brush.
- For right-handed persons, it is always best to begin from the upper-left corner of the surface you are working on.
- Varnish a one-foot square area, and brush in the direction of the wood grain, not back and forth.
- Apply at a temperature of about 70 to 75 degrees Fahrenheit for proper curing.
- You can apply varnish with a brush, pad, or roller.
- Work in a well-ventilated workspace
Steps to varnish wood surface:
- Start by sanding the surface. Use fine grit sandpaper
- Remove all sanding dust
- Thoroughly but slowly stir the varnish. Do it gently to avoid forming bubbles
- Pour varnish into a container
- Add gum turpentine to thin varnish
- Apply varnish slowly with a brush, roller, or pad
- When you are done, proceed to the adjacent square of similar directions.
- Apply the sealer coat. However, the varnish itself can act as a sealer.
- Apply the main varnish coat.
Varnish vs. Polyurethane vs Lacquer vs. Shellac: Differences
Curing & Fastest Drying Time
Varnish takes about 24 hours to cure fully. Its drying time also takes about 30 minutes, making it one of the best finishes with a quick-drying feature.
Polyurethane is also a great and popular finish with a curing time of about 30 days. However, the water-based Polyurethane has a fast drying time of 2 hours. The oil-based Polyurethane may take longer.
Lacquer has a curing time of 2 weeks, and its fattest drying time is 60 minutes.
Shellac, a finish mostly suitable for touch-up work does not take long to cure. Within just 10 seconds, you can have your shellac finish cured. It has the fastest drying time of 30 minutes.
Colors & Tints
Varnish can be tinted with any color of your choice. Polyurethane can be tinted with the use of color pigment. You can also choose to tint Lacquer with different colors. Aniline dye or alcohol-based stain can be used to tint Shellac.
Sheen
Varnish has a relatively low level of the sheen of about 30%. Polyurethane has a very low level of sheen.
Lacquer has a sheen level of 40%-90%.
Shellac has a 3% to 5%=gloss sheen.
Durable & Lasting
Both Polyurethane and Lacquer have more durability compared to other finishes. They can be applied to outdoor woodwork and have the ability to withstand different conditions. They are also a good choice for indoor use.
Varnish and Shellac have durability as well, but not as Polyurethane and Lacquer.
Toxicity
Varnish can be toxic if the solvents and resins are ingested. Polyurethane is also toxic if it is not cured and can be irritating to people who live with respiratory problems. Correct application may prevent it from being toxic. Lacquer is a clear coating that can also be dangerous to swallow. The fumes can be harmful if ingested. Shellac contains methanol which is toxic as well.
Odor
Varnish produces an odor that can even be noticeable after months of application. Polyurethane has isocyanates and VOCs responsible for producing an unrelenting toxic smell. Lacquer has a strong odor and can become concentrated in a newly painted room and may cause headaches in some people. Shellac has a strong smell too but can dissipate quickly after application.
Water Resistance
Varnish has waterproof properties that help to seal woods. To a certain degree, Polyurethane can resist water. Lacquer is a tried and true sealant with amazing waterproof properties. Shellac has a water-resistant property that can withstand water even up to 4 hours.
Heat Resistance
Certain varnish can resist heat moderately. Polyurethane is generally a durable finish that can protect against heat and scratches. Lacquer has heat-resistant features as well when they are exposed to high temperatures.
Application
Varnish is best applied to surfaces such as roof trusses from the atmosphere, windows, doors, and wood protection. Polyurethane is best applied with a brush or roller. It is suitable for surfaces such as floors, furniture, and other surfaces. Lacquer is applied with a bristle brush, preferably a natural and high-quality brush. For Shellac, it is best to use a brush or pad it on wood.
Repair
You can use 0000 steel wool and paste wax to repair varnish. To repair Polyurethane, sanding the surface lightly and wiping it using clean clothe is the best. Reapply a thin coat again. For Lacquer, is best to spray a wet coat on the cracked area to cover it. Once it hardens, the blemish disappears.
Clean Up
Other kinds of finish may require you to get mineral spirit to clean them up when the need arises. However, when it comes to easy clean-up, water-based Polyurethane is the easiest as you don’t need any mineral spirit to clean up. You can use just water as the name implies.
Budget
The budget for these finishes may vary depending on the size of the product and size. However, the budget for varnish ranges from $13 to $20. Polyurethane may cost between $15 to $20. For Lacquer, you must budget between $20 and $25. Shellac requires a budget of $20 to $25.
Shellac vs. Polyurethane
Choosing between Shellac and Polyurethane can be tricky and overwhelming when it comes to finishing wood surfaces. Shellac is a finish that does not contain any amount of VOC, making it the least toxic finish available. However, oil-based Polyurethane remains one of the most toxic varnishes you will ever find. It emits a higher level of VOCs when you apply it. Even after its application, it continues to emit VOCs for a significant time. Water-based Polyurethane on the other hand has low or zero VOCs.
Shellac is a type of Lacquer that doesn’t cure. It can only harden your floor through the environment. It contains denatured alcohol and resin as its two ingredients. You’ll notice a gentle sheen and warm glow whenever you apply Shellac. It reflects only the natural properties of the wood.
Polyurethane is a varnish that finishes and cures at the same time. They can harden through chemical and natural processes. It is a durable finish suitable for wood surfaces. It can either be water-based or oil-based finish.
Lacquer vs. Polyurethane
Lacquer is a varnish and behaves like every other non-curing finish. It is more like water. When applied to the surface of the wood, it absorbs it and forms a stronger bond that cannot be easily disrupted. However, it can peel and discolor after a long time. It is easy to apply and dries quickly like water-based Polyurethane. Lacquer produces a glossy and smooth finish. Yet, it maintains its durability on your wood finish. There are three types of Lacquer: water-based Lacquer, acrylic Lacquer, and nitrocellulose lacquer. Each of the types has its own properties and unique identities. You can easily apply multiple coats with Lacquer.
On the other side of the coin, Polyurethane is a kind of plastic that protects the wood. It can withstand abuse whether it is for interior or exterior use. Although it shows similar identities with a lacquer finish, poly differs significantly. Unlike Lacquer, Polyurethane features a thick texture. It is not easy to apply with mere spray. It has to be thinned with some thinning agent. The drying time of Polyurethane depends on whether you’re using water-based or oil-based type. Coating polyurethane requires sanding. It takes time for poly to dry.
Varnish vs. Polyurethane
Varnish is an older type of finish that is manufactured from solvents, oils, resins, and solvents. At times, people often mistake the term varnish to represent all types of wood-finishing agents. However, there is a difference between poly and varnish. Varnish has lower susceptibility to UV light damage. Thanks to its higher solids ratio, it is suitable for exterior projects. Polyurethane can be either water-based or oil-based plastic resin for wood coating. It can also be used as a wood finish.
While varnish is suitable on deck chairs, outdoor decks, and softwoods, Polyurethane works well on hardwoods, picture frames, bookcases, wood flooring, and desks. Polyurethane is more durable than varnish, although it is prone to UV damage and cracking. Varnish is stronger against UV threats and more flexible. Under suitable conditions, varnish can take up to 6 hours to dry. Water-based poly dries quickly, but oil-based can take up to 24 hours.
Lacquer vs. Varnish
Although both Lacquer and varnish are excellent in adding incredible glossy and shiny finishes. There are differences between them. Lacquer is a solvent-based finish with quick-drying features which can be used on wooden projects. It provides an extremely gloss finish due to the solution content of Shellac in alcohol, creating a synthetic coating for the surface. Varnish is a finish for topcoats with transparency and hardness. Its protective finish help to produce a glossy finish on the surface it is applied on.
Varnish is often preferred if you’re looking satin or semi-gloss sheen finishes as end products. It boasts a high level of protection. When it comes to versatility and protection, Lacquer takes the upper hand.
It offers a higher level of protection and can create matte and high-gloss finishes.
Lacquer vs. Shellac
Lacquer is more user-friendly than Shellac due to the difference between thinners. When you have the right lacquer thinner, you can apply it at cold temperature without any issue. Shellac is a natural finish derived from the lac bug, imparting a warm tone while also adding depth to the grain.
Shellac has the ability to hold color and produce a glossy finish. It can also produce a wide variety of colors. On the other hand, Lacquer can only hold the natural color of the wood it is applied on. Shell. Lacquer requires to be polished before it can dry. But Shellac naturally dries to a high-gloss and shiny finish. Lacquer is more durable and so has become a more popular choice among painters and crafters.
Best for Outdoors
Lacquer is the best choice for outdoor uses. The sun will help to prevent it from fading while ensuring it remains its gorgeousness. Regardless of if you go for the matt or gloss finish, Lacquer remains the best for outdoor use over Shellac. On the other hand, Shellac isn’t a good choice for outdoor use. It produces a white ring if you try to set a wet glass on furniture with a shellac finish. It becomes soft over time if water touches it, wearing away from the surface it is applied on.
Best for Crystal Clear Finish
Lacquer is clear nitrocellulose dissolved in a solvent. However, it helps to produce a crystal-clear appearance when you apply it on surfaces and a hard-wearing finish. Applying it with a sprayer also helps to produce a smoother surface making it the best choice for crystal finish. Shellac is a natural finish that produces a mid-gloss sheen and a lustrous appearance.
Final words
Considering the above differences and features of these different finishes, you would have known the Difference Between Polyurethane, Varnish, Shellac, and Lacquer?. Ultimately, if you are concerned about choosing the easiest spray application with good durability, you may go for Lacquer. A catalyzed lacquer may also be the best option to consider for good spray and durability. Varnish finishes provide an easy brush-on application, making it a great choice.
Shellac is a better choice for most touch-up work and fast work. You can consider working with water-based Polyurethane. However, your choice of selection may also depend on what you want. Choosing the right qualities depends on the application’s importance. Consider the pros and cons to know what will work well for your woodworking.
My name is Mark, and I am a software engineer and the founder of OnWoodWorkingArt.
I grew up with a passion for woodworking and now have my woodworking studio with a group of like-minded friends who love to create woodworking. My dream is to have a more extensive workshop and be able to make woodworking my main business.