Lacquer vs. Polyurethane: Which Should You Use?
Your choice of finish is as important as other vital things in a woodworking project such as your choice of timber and power tool. And what you use to finish the wood can make or break the project.
Although there are various wood finishes that you can use, lacquer and polyurethane are two of the most famous ones and also what many armature and seasoned woodworkers tend to use a lot.
What makes polyurethane and lacquer popular is that overall both do not take as much effort to apply as other wood finishes and clean up is also pretty easy. However, the two have some distinct differences and each will also have some pros and cons.
Understanding what sets polyurethane and lacquer apart will make it easy to pick the perfect finish for your projects.
When you want a clear or transparent finish that shows the wood grain, lacquer is always the best option. And although some woodworkers will sometimes confuse or use the term synonymously with varnish, it is vital to know the two are different kinds of finish.
Lacquer is a resin-based solution that is in most instances emulsified by oils and it dries into a hard and transparent film when you expose it to air. However, there are also some types of lacquer that will have a pigment to provide a darker finish.
There are three common types of lacquer which are acrylic, nitrocellulose and water-based. Acrylic lacquer stays clear for its lifetime and it is a solution to the yellowing problem that is characteristic of many other finishes.
Water-based lacquer, on the other hand, is less toxic and more durable than most other kinds of finishes while the nitrocellulose types form a protective film that can withstand a lot of abuse.
Lacquer absorbs into the wood to form a better and more long-lasting bond. And this is one of the main things that set it apart from polyurethane as the latter is more of a coat for the wood since it is a polymer.
Also, lacquer is one of the easiest wood finishes to apply. It comes as a thinner finish straight from the container, hence making it easy to apply without adding anything. And you can apply most types of lacquer with a spray gun straight from the can.
When you apply lacquer you will get a really hard finish that will make the workpiece highly resistant to damages from water, heat and both alkalis and acids.
You will also need just one coat when using lacquer to finish your wood, and this makes it more cost effective as a single can last long. Adding an extra coat of lacquer is in most cases pointless as it just dissolves into the original one to form a single coat and it does not make any difference.
- Easier to apply. Lacquer comes as a thinner liquid than polyurethane and most other types of wood finishing, and hence making it easier to apply. With most types you do not have to worry about leaving brush strokes on the workpiece as it is possible to spray them to the workpiece from the can directly.
- Fast drying. While polyurethane can take anywhere between one and three days to dry, lacquer only requires about an hour to dry completely. This fast drying capability is a great feature when you have a strict project deadline or just hate to wait for several hours/days for your wood finish to dry.
- Better climate tolerance. Lacquer tends to tolerate changes in climate better than polyurethane. It is one of the few wood finishes that are compatible with various solvents, and so it is possible to add one of these solvents to lacquer to compensate for the weather condition.
- Easy to repair. Although lacquer penetrates into the wood and is quite long lasting, it will not last for eternity. However, unlike polyurethane, it will be easy to repair and remove. For repairs, you only need to add another coat to the wood surface and it will dissolve into the original coat to form a new and better-looking coat.
- Limited scratch resistance. The low solid content in lacquer will result in poor film building properties and this leaves the wood more prone to scratches. With polyurethane, you get a tougher and more scratch resistant film as it is more of a wood protectant than a penetrant.
- High VOC content. Most types of lacquer will have a high VOC content and so they will be more harmful to the environment than polyurethane.
Polyurethane is a common wood finish that you are likely to see in most professional woodworking workshops. And as its name suggests it is basically a plastic in the form of liquid (at least until it dries).
It comes in various finish varieties from satin to glossy, and in two kinds which are water-based and oil-based polyurethane.
Water-based polyurethane tends to dry faster than the oil-based version but still not as fast as lacquer. Also, it is no toxic and easy to clean with water, but it produces some bubbles that make it harder to achieve a smooth and level surface.
The water-based version of polyurethane will not hold up well to heat and chemicals, and so it will be best for things that will not be exposed to the extremes. And they include side tables, desks, and bookcases.
The oil-based types are slow-drying and hence much easier to apply than the water-based polyurethane. And this makes it possible to create a more level surface that will also be smooth and glossy.
But, the oil-based type of polyurethane is harder to clean and also contains some harmful or toxic compounds.
Read More: Oil vs. Water Based Stain
Polyurethane being a polymer, it acts as more of a protective coat for the wood as it does not penetrate deep like lacquer. And this coat offers excellent resistance against scratches, heat, acids, and wear.
This tougher seal that polyurethane creates makes it better than lacquer for use on anything at the seafront as it can also withstand moist salted air.
- Durable coating. Polyurethane might take longer to dry but it forms one of the most durable coatings. Once the plastic hardens, it forms a permanent coat that will last for a long time and protect the wood from scratches and other common elements such as heat and acids.
- Best for wood floors. You will rarely see wood floors finished in anything else besides from polyurethane, and this is also due to its durability. If you apply the right type of polyurethane and enough coats on your wood floors, you can be sure of getting one of the hardest and most durable finishes among all wood finishing types.
- Beautiful appearance. Besides from the obvious protection that polyurethane provides for the wood, many woodworkers also find the finish more appealing. Although lacquer provides a clear finish that highlights the wood grain, the finish that you get with polyurethane is more beautiful on your furniture and other workpieces.
- Long dry time. While lacquer starts to dry in minutes and is dry completely in under one hour, the average polyurethane will take about one day to dry and some can even take a couple of days.
- Harder to repair. In case you make a mistake when applying lacquer, all you will need to do is to add some solvent to correct it. However, with polyurethane, you have to do a lot of sanding and apply another coat. Also, sanding is necessary between coats as urethane will not bond properly without sanding.
- Slower application. Since you have to brush on polyurethane, it takes longer to apply than lacquer which you can spray straight from the can using a high volume and pressure spray gun.
Both polyurethane and lacquer would be great for any woodworker to have in the workshop as they are some of the best wood finishes out there.
But for those that are looking for something that is fast drying, easy to apply and more absorbent, lacquer is the best choice between the two.
Also, lacquer is the ideal pick for those that are keen to show the natural grain of the wood as it provides a clear finish.
However, if you are in the market for a tough and durable protectant finish that also creates a more beautiful look, polyurethane is a great choice. Also, polyurethane is the best choice when working on wood floors.
Overall, lacquer seems to have an edge over polyurethane due to the ease of application and shorter drying time.