Are you looking for smooth finish for a woodworking or furniture project? Two of the top contenders for varnish are polyurethane (which itself can be oil- or water-based) and polycrylic. These are both clear, glossy finishes, and are claimed interchangeable—so what’s the difference?
Deciding on the right finish can sometimes be a daunting task, or even trial-and-error, which can be expensive. I’ve been there! This article will explain each of these products, the pros and cons of using them, and make your polyurethane vs polycrylic dilemma easier to resolve.
Polyurethane vs Polycrylic: What is the difference?
The essential difference has to do with the application of these finishes—how thin the coats should be, how long they take to dry, and so on. Both polyurethane and polycrylic are long-lasting and scratch-proof, but polycrylic dries much faster than its counterpart.
But drying time is not the only factor you should take into consideration! There are several more subtle differences in these finishes that can make or break your project’s final look.
What is Polyurethane?
You can think of polyurethane as plastic in liquid form. It is usually a brush-on finish, which means you have to be careful to keep the coating consistent. You don’t want an uneven or bubbly finish. Since polyurethane can take up to twenty-four hours to dry, you can take your time.
Always be careful when using polyurethane! Because it is toxic, you should apply this finish in well-ventilated areas, and allow the project to dry completely before bringing it into an enclosed space. Liquid polyurethane can be toxic to the skin as well, and is highly flammable.
There are two types of polyurethane: oil-based and water-based.
Oil-based polyurethane tends to be more durable, water resistant, and heat resistant than water-based polyurethane. It also has a slight yellowish tint which is more noticeable on light-colored woods and paints.
Water-based polyurethane dries faster and is more transparent (though in my own experience a yellowish tint can appear after some time). It is also less toxic than oil-based polyurethane.
What is Polycrylic?
Polycrylic, a water-based finish, is more versatile than its polyurethane counterpart. Because polycrylic is a completely transparent finish, it can be used over light woods and paints. This product is also less expensive than polyurethane, if money is a concern of yours.
This finish is safer to use if you have children or pets. There’s no need to worry if you make a mess with polycrylic: you can easily clean it up with soap and water. Use a soft rag to clean your skin and wash your clothes as soon as possible to prevent permanent stains, if necessary.
It is recommended that you do not use steel wool to clean surfaces finished with polycrylic. A stray strand could become lodged in the finish and rust, creating an ugly stain.
Polyurethane vs Polycrylic: Suggested Projects
When it comes down to it, your project will be the deciding factor in which product you finish with.
For example, if you’re finishing a tabletop that will be exposed to water, consider using an oil-based polyurethane. If you’re running late on a project or it just needs to dry quickly, polycrylic may be the best choice.
Polyurethane can be used for:
- book cases,
- picture frames,
- wardrobes, and
- wood flooring.
When using polyurethane, some of the most important questions to ask yourself are:
- Where am I going to apply it?
- Will this project be safe and out of the way while it dries? (That is, is it possible any children or pets could be exposed to toxic fumes, or could bad weather affect the finish?)
- How much time do I have to complete it?
- Does it matter if my project could yellow slightly?
Polycrylics are good with interior projects, such as:
- doors, and
- cabinets, as well as
- kids’ furniture and play areas.
When using polycrylic, ask yourself these questions:
- How large is my project? (Because polycrylic dries quickly, sometimes the finished product can look uneven if applied too late.)
- Can I lay my project flat to apply the coat? (Polycrylic can run if applied too thickly to vertical wood such as doors, so try to apply thinly and watch for drips.)
Sometimes even people with a lot of experience use incorrect application techniques. These mistakes can range from using the wrong kind of brush to simply stroking up and down rather than forwards and back.
This YouTube video shows you how to apply a polyurethane finish without bubbling, running, or puddling.
The creator of the video, Paul, explains the difference between several types of polyurethane, and demonstrates good and bad applicators to use. His application technique comes towards the end of the video after he delivers a lot of helpful tips that can apply to polycrylic users as well.
This YouTube video shows you how to apply a polycrylic finish, achieving the same smooth, glossy finish as the polyurethane.
It can sometimes take longer for polycrylic users to finish, depending on the size of the project and how fast the finish dries. Despite the time constraints, you should try to achieve as smooth an application as possible to prevent bubbling and unevenness.
(A personal note: the creator of this video uses a foam brush, which in my own experience can leave rough patches in my finish. I prefer to use brushes prescribed by Paul from the polyurethane video.)
Related: Top 7: Best Woodworking Clamps
Let’s summarize the difference between polyurethane and polycrylic finishes. It is important to consider these points in context of both your project and your situation—that is, whether you’re working from home and/or living with others.
- liquid plastic
- available in oil base and water base
- toxic and flammable
- good for exterior and larger projects
- completely transparent
- easily cleaned up with soap and water
- safer to use around children and pets