Polyurethane vs Lacquer (Do You Need Both)?

When choosing a sealant for your furniture, most painters will advise you to go for lacquer or polyurethane. Both of these top coats are durable and easy to maintain. So what’s the difference between both top coats?

Polyurethane on one hand is a sealant that leaves a thick, strong, and moisture-resistant film on wood. Due to the thickness of the paint, polyurethane rarely penetrates wood fibers.

Lacquer on the other hand isn’t as thick as polyurethane. Lacquer is a thin sealant that has a light flow. The thinness of the sealant makes it penetrate porous materials like wood and plaster.

So which of these top coats is the best? And which do you need for your task? Let’s go into detail about both top coats. First, let’s check out polyurethane and what the top coat is used for?

What is Polyurethane?

What is Polyurethane?

Polyurethane is a plastic-like sealant. There are two types of polyurethane finish; oil-based and water-based polyurethane. Each type of polyurethane has its features, drying time, and strength. But oil-based polyurethane is the most common.

Polyurethane is a polymer that contains polyol and diisocyanates of isocyanate compounds. The reaction of the polyol (alcohol) with the isocyanate or diisocyanates creates the polyurethane finish.

Polyurethane is very strong, durable, and common for its water resistance. The finish is used to cover furniture and interior walls.

There is also exterior polyurethane that is designed to be used on outdoor furniture and exterior walls. These polyurethane products have additives that make polyurethane finish moisture and UV resistant.

Exterior polyurethane is usually oil-based and designed to be very thick. So it’s best to apply with a paintbrush or thin before using the polyurethane. You can thin oil-based polyurethane with turpentine or mineral spirits. Water-based polyurethane should be thinned with water.

However, polyurethane has one flaw. The sealant tends to yellow over time and this is most common with the stronger oil-based polyurethane. Now let’s check out what lacquer is used for.

What is Lacquer?

What is Lacquer?

Lacquer is a very common sealant used to finish wood and stains. Lacquer has a thin flow and as such is a light sealant. This means lacquer is very easy to apply and dries quickly. Lacquer finish is also very durable, glossy, and smooth. The durability of lacquer is because it penetrates the wood. This gives it a stronger grip and such, increased durability.

Lacquer is commonly used in indoor areas of the home where detail is important. This includes shelves, kitchen cabinets, drawers, and the likes. What’s common with these areas is that they aren’t heavily used and as such can be protected with a thin sealant like lacquer.

However, lacquer has one flaw. The paint isn’t very durable and tends to not last very long on outdoor furniture or exterior walls. But how does lacquer fair when compared to polyurethane? Let’s take a closer look into the paint make-up and features of both top coats to find out.

Polyurethane vs Lacquer: Head to Head

First, let’s start at the beginning, the paint make-up.

Paint Make-Up

In terms of paint make-up, lacquer has natural make-up while polyurethane has synthetic make-up. Lacquer is gotten from natural substances like tree sap. Also, lacquers contain shellac which is secreted by the female lac bug.

Polyurethane however is gotten from catalysts, paint chemicals, additives, resins, and alcohol. The paint make-up makes lacquer have a thinner flow compared to thicker polyurethane.

Paint Adhesion

Lacquer adheres better to wood than polyurethane. This is due to the thinness of the lacquer. Since the paint is thin and runny, it tends to soak in wood fibers quickly and easily. This gives it increased grip inside the material used.

Polyurethane on the other hand has a thicker flow and as such is less likely to soak in wood fibers. Polyurethane is known to sit on the material and produce a thick and durable film. Since poly doesn’t soak in wood as much, its paint adhesion is not as strong as lacquers.

Durability

Both lacquer and polyurethane are very durable finishes. Both top coats if applied correctly will last at least a decade on wood before you start to notice chipping. However, polyurethane is more durable than lacquer.

This is because polyurethane is mixed with different additives that give the finish a plastic-like film. This plastic finish is resistant to moisture, dents, and even heat. Polyurethane finish can expand and contract based on temperature changes.

Lacquer on the other hand has a shortage of additives and chemicals meaning that lacquer can be easily affected by dents, dust, and chipping. This makes lacquer less durable than polyurethane.

Paint Thinning

Polyurethane has to be thinned before you apply it. This is because the paint has a very thick consistency and laying polyurethane on thick means it will take forever for the paint to dry.

Asides from that, the polyurethane will be uneven and bumpy. Polyurethane can be thinned with turpentine or water depending on the paint’s base.

Lacquer however can be applied without thinning first. It’s not advised to even thin lacquer because the top coat already has a thin flow.

Related Read: Can You Apply Polyurethane Over Shellac?

Paint Fumes

You must have noticed that paint usually have an odor. The odor you perceive is the smell of paint chemicals reacting to the atmosphere after being applied. With lacquer, the smell of the paint chemicals is toxic and can be harmful if inhaled in large quantities.

However, several varieties of lacquer paint don’t produce toxic fumes. Acrylic lacquer, water-based, and nitrocellulose lacquer are known to be non-toxic.

Polyurethane has that offensive smell and paint fumes regardless of the type of polyurethane that you use. This is because of the presence of isocyanates in the paint coating.

All types of polyurethane contain either isocyanates or diisocyanates. Both these substances shouldn’t be accumulated by humans in large quantities as they will cause health issues. So in terms of paint fumes, you’ll be safer with non-toxic lacquer.

Indoor or Outdoor?

Because lacquer is safer to use, the paint is commonly used indoors. Lacquer is common on furniture like cabinets and shelves. Also, since lacquer has a thin or light flow, it is less durable and thus more ideal for indoor surfaces that won’t see heavy traffic.

Polyurethane however is more ideal for outdoor or exterior application. This is because the paint is more durable.

Asides from that, polyurethane usually has additives that make the paint coating resistant to UV rays of the sun. Polyurethane also has a thick plastic sheen that is resistant to water in case of rainfall as well as dust and stain-resistant.

Exterior polyurethane is the best for outdoor or exterior applications.

Ease of Application

Lacquer is easier to apply than polyurethane. For starters, you don’t have to thin lacquer before applying it. Polyurethane however will need a solvent or paint thinner to be applied smoothly.

Also, there is a higher risk of ruining polyurethane than lacquer while applying the paint. Lacquer is also less likely to reveal brush strokes and marks after application.

Lacquer also dries quickly which means you can shape the finish sooner making you complete the paint job quicker. Polyurethane however will require several hours and up to 3 days before you can shape the finish.

Paint Variety

In terms of paint variety, you have a broader range of paint types to choose from with lacquer. You have acrylic, nitrocellulose, water-based, oil-based lacquer, and other types. Also, lacquer comes in a variety of colors so your choices aren’t limited.

Polyurethane gives you a limited variety. It’s usually just water-based or oil-based polyurethane. However, you can also get a satin, medium gloss, or high gloss finish.

Clarity of Finish

In case you don’t know, polyurethane and lacquer are both clear top coats. When used, lacquer and polyurethane produce a clear finish but the clarity of polyurethane idle any last long.

Polyurethane especially oil-based polyurethane tends to yellow after some time. Lacquer will remain clear for several years.

Paint Cleaning and Maintenance

With both paints, you can easily wipe off stains with a rag and soapy water. However, polyurethane tends to attract dirt and dust nibs especially while the paint is drying. Since poly takes so long to dry, this gives enough time for dust to accumulate on the paint coating.

The Cost of The Finish

Lacquer finishes tend to cost more than polyurethane. Though both paints have around the same price tag, you’ll need to purchase more quantities of lacquer. This is because lacquer is a thin paint and as such, you’ll need multiple coats to fully cover an area.

Also, it’s best to apply lacquer with a spray gun or paint sprayer due to its thinness. But if you don’t have a sprayer already, buying one will cost some cash. Also, renting will cost you more than buying a paintbrush for polyurethane application.

So which of these top coats do you need? Let’s find out.

Related Read: Can You Paint Over Lacquer?

Should I Buy Polyurethane or Lacquer?

The answer depends on a few factors. Before deciding on which of the top coats to go for, answer a few questions.

How Much Do You Want To Spend?

Though both paints cost around the same, lacquer finish tends to require more paint and as such more money. This is due to the thin nature of lacquer.

Indoor or Outdoor?

If you want to cover an indoor material, you can go with lacquer. For outdoor application, go for polyurethane preferably oil-based exterior polyurethane.

How Much Protection Do You Need?

If you want to pick a sealant for high traffic or heavily used areas like tabletop, chairs, walkways, and the likes, polyurethane is your pick as it is more durable.

If the material to be painted will not see a lot of action, you can go with lacquer paint.

Final Words

Overall, polyurethane and varnish are both great paints. Both top coats are durable, strong, and water-resistant.

The decision on which to go for depends on your taste and needs but I hope the guide above has been helpful.

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