With woodworking with kitchen cabinets or other furniture items around your home, you’ll find many finish options. For example, to increase the wood-protecting properties and stop it from getting scratched easily, one finish can be applied on top of another.
Many people, however, wonder, can you put lacquer over polyurethane? In our guide, you can find the long answer to this question, which happens to be no. You can’t use poly over lacquer as they are two different materials.
By the end, you’ll find the best protective layer for your wood surface, be it wood furniture, cabinets, or wooden floors. You’ll see various products and how you apply lacquer or apply poly to get that prized high gloss finish you want. (Learn Can You Drill Into Spackle)
What Finishes Can Be Applied Over Lacquer?
Knowing what you can apply to lacquer means you need to understand the lacquers.
Despite their similarities, the lacquer is not confused with varnish, as its durability and consistency are far lower than shellac. The lacquer tree produces lacquer as sap, hence its name.
What is Wood Lacquer?
Lacquer thinner is made from lacquer tree sap resin, and synthetic lacquers offer many uses and benefits.
Below are lacquer types.
Acrylic Lacquer
Acrylic lacquer dries rapidly, and if you don’t want the yellowing appearance that nitrocellulose lacquer finish products have on interior wood surfaces, this is a perfect alternative.
This is because of the acrylic-based resin in the composition, which gives the lacquered wood an opaque-transparent aspect. The most popular version is the CAB-acrylic lacquer finish.
Water-Based Lacquer
Water-based lacquer finishes are the way to go if you care about the environment.
A water-based lacquer finish is non-toxic but less combustible, which is a big plus in dry climates where lacquered furniture could quickly catch fire.
This type is popular for lacquered furniture and has become increasingly popular among enterprises that work with wood, such as furniture, repair, and building.
Although water-based lacquer is the safest alternative, you should still take proper safety precautions.
Nitrocellulose Lacquer
For many decades, nitrocellulose lacquer was the most regularly used lacquer until the present surge of alternative lacquers became accessible.
Most lacquers of this type are plant-based solutions containing nitric and sulfuric acids and cotton, which helps the breakdown of nitrocellulose and serves as an emulsifier.
The lacquer finish dries quickly, like other lacquer finishes making it ideal such lacquer finishes ideal for high-volume industries like furniture and automobiles.
When brushing lacquer, you only need one coat, which is a fantastic bonus as applying only one layer saves time and money.
Acrylic lacquers have some drawbacks, including they may shrink, and resulting cracks can appear.
Yellowing and scratching are also found in such a lacquer finish, and lacquer finishes are affected by heat.
In addition, because moisture can become trapped in an application, you’ll find you have an opaque finish. You can use a slower-drying lacquer thinner to thin the lacquer consistency to fix this.
Catalyzed Lacquers
Not only do catalyze lacquers contain nitrocellulose-based resins, but they also contain urea-based resins, which offer an extremely durable finish and make this lacquer water-resistant.
Once an acid catalyst is introduced to the lacquer, the chemical can cure. If you prefer to mix your own post-catalyzed lacquer, be conscious of your proportions and follow the directions carefully. (Learn Can You Keep A TV In The Garage)
Can You Use Urethane Clear Over Lacquer?
Scratches and water damage are common problems with lacquer finishes. Before you start, you’ll need to test the furniture to see what kind of lacquer finish it has, whether regular or catalyzed.
Catalyzed lacquer offers a durable coating and is long-lasting. Use a cotton tip swab dipped in lacquer thinner or mineral spirits to dab an inconspicuous place on the object.
If the lacquer becomes sticky because of the thinner, the finish is regular lacquer, yet the thinner will not affect catalyzed lacquer finishes.
Second, polyurethane is not the best choice when painting over a wooden surface covered in lacquer finishes.
Polyurethane coats won’t stick to the lacquer and peel off over time with everyday use.
Use an alkyd varnish instead. Alkyd varnishes are polyester resin that adheres to surfaces better and is easier to fix.
Alkyd varnishes offer a more natural appearance and are less prone to fading. Ensure the alkyd varnish with polyester resin offers the same finish as the lacquer, and a gloss finish is a safe choice.
Lacquer should never be used over Alkyd varnish since it has a stronger solvent than varnish and will eat away at the finish underneath.
Is Lacquer Better Than Polyurethane?
When coating any wooden surface where you want to see the wood grain, you’ll need to pick between adding lacquer or should you apply polyurethane?
Here you can see a few differences between the two compounds.
Application
Polyurethane is more challenging to work with because of its thick nature, so you can’t add a poly finish in thin coats to speed up drying.
You’ll need a good brush, but applying polyurethane is more about technique as this helps prevent brush marks from ruining the finished product.
Lacquer is fluid and requires a low-pressure sprayer, protective eyewear, and a woodworking respirator mask during application. However, once you have the equipment, the application is simple. (Learn How To Dispose Of Glass Table Top)
Finish Quality
If we’re talking about durability, polyurethane over lacquer is the winner. While it is harder to apply when applied correctly, oil-based polyurethane offers a strong and durable result and will protect the wood underneath.
Many lacquer finishes are, however, extremely durable nowadays. However, over time, it is more prone to yellowing and scratches. If quality is essential, putting poly on your wood is the way.
Drying Time
Most woodworkers use lacquer because it dries faster than a poly finish. However, it comes at sacrificing durability, so you should choose poly over lacquer.
Polyurethane dries in hours, whereas lacquer can dry in as little as 10 minutes.
Lacquer and polyurethane both work well as wood finishes. However, you must select the one based on the project, the turnaround time, and the desired outcomes.
Polyurethane is essentially a liquid version of plastic. Professionals consider it the best protective coating for many surfaces, such as wood, plastic, primed metal, paper, some fabrics, unglazed masonry, and rubber.
It has a thicker consistency than lacquer, but you can thin it to match lacquer’s consistency and use a spray nozzle to apply it.
There are two types of finishes available: water-based and oil-based, as well as matte, semi-gloss, and gloss.
Oil-Based Polyurethane
If you need a long-lasting finish, oil-based polyurethane is the way. It looks great, but it also dries slower than water-based polyurethane.
Always work in a well-ventilated environment and wear protective gear. Oil-based polyurethane is hazardous, but it also has a powerful stench. In addition, while it seeps and absorbs into the wood, the extremely durable polyurethane top is absorbed into the wood.
It can also be used on many other materials.
When using oil-based polyurethane, a few small drawbacks exist. And that disadvantage is that it yellows if you have applied it on a light-colored wood. You will also need mineral spirits for any clean-ups.
Oil-Based polyurethane combines and handles heat well for wooden floors and tables.
It makes oil-based polyurethane so appealing to its ability to withstand moisture, allowing you to utilize it on your patio.
Water-Based Polyurethane
This choice should be favored because it is more environmentally friendly and less hazardous.
Because it is heat-sensitive, it should not be painted on surfaces that are exposed to heat, such as in the kitchen or your workshop. Although lacquer dries a little faster than its oil-based equivalent, it still dries faster than both. (Learn How Long Does It Take For Loctite To Dry)
One advantage is that you can expect a simple clean-up when you’re finished.
Polycrylic
This is the most environmentally friendly of all polyurethane products, as it is the least hazardous and emits the most negligible odor of all water and oil-based polyurethanes.
It takes only two hours to dry initially, but it will still need to cure, taking up to 24 hours.
Polyurethane Advantages and Disadvantages
When determining which product to use, you should weigh the benefits and drawbacks of each alternative. Although each product serves the same basic purpose, they differ in durability and finish. Take a look at the list below for some of the benefits and drawbacks of polyurethane.
Pros
- Oil-based polyurethane is durable
- The poly coating is heat-resistant
- Water-based poly and polyacrylic are less toxic with fewer odors
- Water-based poly and polyacrylic dry fast
Cons
- You can see a yellow tinge when painted on light surfaces
- You need to follow safety measures
- Not very heat resistant
- Not hardy or long-lasting
- It takes a long time to dry and cure
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Lacquer Application
The most convenient option. Because of its thin consistency can be applied from a spray can for a smooth, even application.
It’s easier to get a smooth finish on smaller surfaces than bigger ones.
When spraying, always wear a respirator mask to protect your lungs from fumes from the spray canister and an eye mask to protect your eyesight from lost vapors.
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Brushing on lacquer vs. polyurethane dries quickly, so you’ll need to work swiftly.
Because of the thinness inconsistency, you may need several coats as you’ll get a thin, even coat. In addition, you’ll find sanding needed when you add more layers or re-finish an older piece of furniture.
If you’re making a comparison, would you choose poly over lacquer? Alternatively, lacquer over polyurethane?
Lacquer is the easier alternative in terms of application because it does not require a thinner to pass through a spray nozzle.
Even if you are not spraying but brushing, you will notice fewer remaining brush strokes. Remember to practice horizontal brush motions rather than vertical brush motions.
- Like many other projects, the hardwood surface needs to be prepared before it can be lacquered.
- To do so, lightly sand the surface to remove any irregularities. After that, you’ll need to dust off and clear up any dust particles from the dusting before you can begin lacquering.
- After applying your first thin layer of lacquer and giving it enough time to cure, you’ll need to sand it down again.
- To give it gentle smoothing, use 320-grit sandpaper.
- Any dust left over from the sanding must be removed before applying the next coat.
- Repeat until you’re happy, which usually takes three or four coats.
Polyurethane Application
When applying an oil-based polyurethane, you must use a natural-bristle brush, while water-based polyurethane products require a nylon-bristled brush.
- Some people like to apply polyurethane with a foam brush, a roller or even rub it on with a cloth.
- The initial preparations for the wooden surface area include sanding it down to smooth it out and laying wood-grain filler on top.
- Working with the grain yields the best results, so paint the poly in that direction with large, lengthy strokes to produce an equal surface.
- After the initial layer has dried for the appropriate period, a light sanding is required.
- This aids in the adhesion of the two layers. You can sand down the surface with 320-grit sandpaper and remove the dust afterward.
- You can add another layer after that, but two coats should suffice.
