Polyurethane is usually applied with a paintbrush. But, using a paintbrush over a large surface is tedious and time-consuming. So, can you apply polyurethane with a roller?
You can apply polyurethane using a roller, but you must use the right type of roller per type of polyurethane. The best roller for polyurethane is a lambswool roller.
The lambswool roller can absorb and apply oil-based polyurethane smoothly. You can also use a foam roller to apply oil-based polyurethane, but never use it for water-based polyurethane.
Before applying polyurethane with a roller, you must dip the roller into mineral spirits. The mineral spirits will prevent the roller from absorbing too much polyurethane and prevent bubbles.
Types of Polyurethane:
There are two types of polyurethane; oil-based and water-based. Can you use a roller for both of these types?
You can use foam, microfiber, and lambswool rollers to apply oil-based polyurethane. Oil-based polyurethane has a thick flow, so these rollers absorb the polyurethane well.
The thick flow of oil-based polyurethane allows the roller to spread it smoothly and without brush marks. However, oil-based polyurethane takes longer to dry, especially if applied with a roller.
You can only use certain types of rollers to apply water-based polyurethane. For instance, you can use fiber and lambswool rollers for water-based polyurethane, but you can’t use a foam roller.
Since water-based polyurethane has a lighter flow, you can only use specific rollers to apply it. For instance, foam rollers are porous and can absorb more water-based polyurethane than needed. This results in uneven coats. So, you shouldn’t use foam rollers for water-based polyurethane.
However, fiber and lambswool rollers will spread the water-based polyurethane evenly.
A Roller Spreads Polyurethane Equally
You will get an even finish if you roll on polyurethane because the roller applies polyurethane evenly regardless of the direction you roll. Also, a roller will prevent you from overapplying polyurethane in some areas.
When you use a roller to apply polyurethane, the wide body of the roller allows you to cover more areas in one roll than any other tool. This is the difference between a roller and a paintbrush. You can overapply polyurethane using a paintbrush, while you can’t with a roller.
Paint Roller Types for Polyurethane:
The paint roller must be lint-free and absorb oil-based polyurethane evenly. Also, the roller shouldn’t leave paint streaks behind.
Here are the types of rollers recommended for polyurethane:
The foam rollers are designed using a commercial foam material. These rollers have impressive absorption, making them ideal for absorbing and applying oil-based polyurethane.
However, foam rollers are not ideal for water-based polyurethane. Foam rollers will cause streaks and paint drops when used with water-based polyurethane. Also, foam rollers aren’t very durable.
Microfiber rollers are woven paint rollers wrapped with a layer of microfiber cloth. The cloth has short and small fibers causing the roller to apply multiple layers of polyurethane without streaks or marks.
The microfiber roller is a great roller for water-based polyurethane. The roller is durable and can be used for multiple polyurethane applications as long as the roller is well-maintained.
Lambswool roller is gotten from lamb wool. The wool is knitted together to prevent the layers from separating or pulling apart.
The lambswool roller has a synthetic backing that makes the paint application faster and easier than other rollers. In addition, the soft nature of the roller makes it possible for the roller to fit in bumps and release polyurethane evenly. However, lambswool rollers are expensive.
Tip: To get the best finish possible, always buy high-quality rollers that are compatible with the type of polyurethane you will use.
Pros & Cons of Using a Roller For Polyurethane
Here are the advantages of applying polyurethane with a roller:
- Using a roller for polyurethane saves you time as you cover more space faster.
- A paint roller doesn’t leave brush marks behind once the polyurethane dries.
- Using rollers correctly will give you a smooth polyurethane finish.
- You can use the same roller to apply different types of polyurethane.
- Rollers are ideal for large walls and floors due to their quick application.
- You get to re-coat polyurethane quicker.
Here are a few shortcomings of using a roller for polyurethane application:
- Rollers can’t apply polyurethane on corners and curves, so you’ll still need a paintbrush for touch-ups.
- High-quality rollers are expensive.
- Using rollers to apply polyurethane increase the chances of paint bubbles.
- Before applying polyurethane with a roller, you must dip it into mineral spirits or turpentine.
How to Roll on Polyurethane?
Applying polyurethane with a roller is an easy task. However, you need the right instruction and tools.
Here are the tools that you need for this task:
- Mineral spirits
- A clean paint bucket or plastic container
- Painters tape
- Polyurethane paint
- Polyurethane paint roller (lambswool or fiber roller)
- Lacquer thinner
1. Prep Work
First, prep the surface you will paint. If you want to paint a wall, remove all objects on the wall (wall sockets, photo frames, etc.). To paint a floor, remove all the furniture. If it’s a wooden surface, clean it.
Cover or tape objects with a painter’s tape for objects you can’t move.
Next, you must wipe the surface and apply a primer if required. A primer will produce a smooth and even layer for the polyurethane to stick to.
2. Sand the Surface
Polyurethane sticks to well-sanded surfaces better. However, if you primed the surface, you don’t need to sand it since polyurethane will stick to a primed surface.
However, if you apply polyurethane on a bare surface (such as wood), you need to sand the wood to remove loose dirt and bumps. To sand the wood, use 180-grit sandpaper.
Sanding will produce a lot of dust — so wipe the surface after sanding.
3. Pour Out the Polyurethane
To apply polyurethane with a roller, you must pour the polyurethane into a large clean bucket. With a paintbrush, you can dip the paintbrush into the polyurethane container, but a roller has a larger body and doesn’t fit into the polyurethane container.
Check the manufacturer’s instructions to know if you should thin the polyurethane or not.
You also must pour a few cups of mineral spirits into a flat container or tray.
4. Apply the Polyurethane
Before you dip the roller into the polyurethane bucket, you must dip the roller in mineral spirits. The mineral spirits will prevent the roller from absorbing too much polyurethane. However, you should damp the roller with mineral spirits and not soak it.
To apply polyurethane with a roller:
- Dip the roller into mineral spirits.
- Shake the roller to remove excess mineral spirits.
- Put the roller into the polyurethane take and allow it to absorb the polyurethane.
- After a few seconds, take the roller out and apply the polyurethane.
Don’t press the roller into the surface as it can cause paint bubbles and streaks. Instead, move the roller back and forth until you apply all the polyurethane. Once you apply all the absorbed polyurethane, dip the roller into mineral spirits first, then dip it into the polyurethane and apply it.
5. Apply a Second Coat
When you apply the first coat, leave the polyurethane to dry for at least 3 hours before applying a recoat. While you wait for the polyurethane to dry, you must prevent the roller and paint from drying up.
To prevent the polyurethane roller from drying, put it into a plastic bag and then into a fridge. This prevents the roller from drying or turning sticky. Once you need a second coat, remove the roller from the fridge and re-use it.
Before applying the second coat of polyurethane, dip the roller into mineral spirits. You need 2-3 coats of polyurethane for proper coverage. Before applying the third coat of polyurethane, let the second coat dry and put the roller into a fridge.
After rolling the polyurethane, clean the rollers and other painting equipment.
How To Clean a Polyurethane Roller?
Here are the tools you need:
- Paint roller squeezer
- Mineral spirits
- Dish soap
- A bucket of warm water
- A metal comb
Here is how to clean your polyurethane roller:
- After applying the last lap of polyurethane, shake off the excess polyurethane left on the roller. You can also use a paint roller squeezer for this.
- Mix dish soap with warm water and soak the roller in the soap mixture.
- After a few minutes, remove the roller and wash off polyurethane residue.
- Dip the polyurethane roller in mineral spirits and use a metal comb to clean and untangle the roller. This will also remove stuck polyurethane paint in the roller.
- When the polyurethane roller is clean, rinse it in cold water and store it properly.
- If the roller isn’t completely clean, you can repeat the steps.
In summary, rolling on polyurethane is possible. But, you need the right type of roller for the type of polyurethane.
For instance, you can use microfiber and lambswool roller for water-based polyurethane. For oil-based polyurethane, you can use a foam roller too.
Also, you must wait until the polyurethane dries before applying a recoat. This prevents sticky polyurethane and uneven finish.