How To Spray Polyurethane With Airless Sprayer?

Polyurethane is one of the best materials used for floor finishing and wood finishing. It provides solid shine and high durability for the surface.

The paint market is full of different kinds of materials but polyurethane is a very unique spray, particularly for wood. As it is available in various types so the spraying techniques also differ according to the size of the project.

Spraying polyurethane with an airless sprayer is very easy if you handle it accurately. With a little prep work, you can use an airless paint sprayer to spray polyurethane. You can do it better and faster than a paintbrush.

Painting Polyurethane With The Airless Sprayer

Polyurethane is a coating material usually used to protect wooden surfaces. It can be applied with brushes and rollers but they cause scratches and stains on the surface.

That’s why the experts prefer spraying polyurethane with an airless sprayer which produces a beautiful finish coat and saves money and time.

Wagner introduced airless sprayers especially for small jobs at the house, like painting doors, fences, and small pieces of furniture. It can deliver a large quantity of paint in a short time. It can be used easily.

What Happened When You Spray Polyurethane?

When you spray polyurethane with an airless sprayer, the paint coat dries soon leaving a little chance of falling dust.

You can also control the thickness of the paint coats easily. On the other hand, if you apply polyurethane with brushes, they can leave bubbles on the surface.


An airless sprayer provides the quality of work and finishes coating in very less time. Polyurethane is a liquid plastic and a little difficult to apply.

So for understanding how to spray Polyurethane with Airless Sprayer, this article will guide you step-by-step about using Wagner or an airless sprayer thoroughly.

How To Spray Polyurethane With Airless Sprayer?

Polyurethane is a solid plastic-type material, so there is a common question always asked that can you spray polyurethane with an airless sprayer? The answer is absolutely yes.

When you start spraying polyurethane with an airless sprayer on some surfaces, you have to follow the instructions.

So, check the complete process discussed below:

#1. Arrange The Necessary Supplies And Prepare The Workspace

First of all, prepare the workplace where you want to start your spraying work. The place must be neat and clean. Spread some plastic sheets on the floor to avoid drops of the liquid.  A painter’s tape can be used for this purpose.

Arrange other required things like pair of gloves for your safety, breathing protection to handle the paint chemicals, fully covered glasses for your eyes, etc.

You should also arrange electricity and lights. The area must be ventilated and away from the dust.

#2. Prepare or Sand The Painting Surface

Next, sand the surface before spraying the polyurethane. Your painting surface must be clean and dirt free. Sanding will help you to level the surface for applying polyurethane smoothly. Always sand the surface with a fine-grit sandpaper.


You must take care, if there are bugs or dirt on your surface, you can’t get the perfect finish.

#3. Thin The Polyurethane Using Right Thinner

For getting a fine finish, pour the right amount of polyurethane into the thinner to make it ready for spraying. It will help the polyurethane to flow through the nozzle of the sprayer easily.

It is necessary to thin water-based polyurethane using water or solvents like alcohol and oil-based polyurethane using lacquer thinner or mineral spirits. Keep the ratio 4:1 so the polyurethane flows better. Otherwise, the polyurethane will lose its color and consistency.

However, you can apply a coat of polyurethane without mixing thinner if you want your desired coat without it.

#4. Set Up or Prepare Paint Sprayer

While spraying polyurethane with Graco airless sprayer, first you should clean and wipe the paint sprayer. Then pick the right key or tip to attach to the sprayer. The tip should be between 1.0 and 1.5mm.

For getting a fine finish, always select the quality sprayer with an adjustable knob, it will enable you to control the quantity of paint flow through the nozzle.

The paint sprayers often come with different spray nozzles. You will have to set up the sprayer to adjust the right amount of paint coming through the tips.

#5. Test The Sprayer

When you have completed the primary essential steps (adjusted the gun and prepared the mixture of polyurethane), test the sprayer first to see if it sprays smoothly and dries well.

If there is any issue, add the thinner again to polyurethane, adjust the knob, and test again to get the required result.

#6. Start Spraying Polyurethane

After testing, when you got the desired result, can you spray polyurethane with a Wagner sprayer? Yes, of course, don’t hesitate now. Start spraying polyurethane with an airless sprayer. Just keep the following things in mind;

  • #1: There should be 10 inches distance between the nozzle of the sprayer and the surface to avoid splashes.
  • #2: Either spray polyurethane parallel or vertical and ensure that the entire surface is sprayed well.
  • #3: Stay a short time before applying the next round of spraying coats.
  • #4: Apply 2 to 3 coats of polyurethane for covering the surface accurately.
  • #5: Let each coat dry at least 3 hours before recoating.
  • #6: Sand with 320-grit sandpaper before spraying a new coat of polyurethane.
  • #7: Don’t sand after the final coat.

#7. Let The Surface Dry and Clean

Let the polyurethane dry at least for 3 days, clean the surface using water and then you can use it.  You must remember, that if you spray oil-based polyurethanes with Airless Sprayer, the surface requires a lot more time to dry. So, take care and enjoy.

Here is the video tutorial:

YouTube video


You can spray both types (oil-based or water-based) of polyurethane with a pump sprayer. But you have to follow the simple steps explained above in detail.

If you have an airless sprayer and the exact polyurethane, a well-ventilated workplace, and all other necessary supplies with you, this article will be surely fruitful and 100% helpful for you.


Hi, Cristopher here. I have been working in the home improvement industry for the past 15 years, and I have developed strong expertise in spray guns and paint sprayers. I have a deep understanding of how these tools work and how to get the best results from them. In addition to my practical knowledge, I am also running this website dedicated to sharing tips and tricks for using spray guns and paint sprayers.

John Smith

John Smith is a professional artist and painter with over 10 years of experience using spray guns in his artwork. He has been featured in various exhibitions and galleries throughout the United States and Europe. He is also a passionate educator, having taught painting techniques and spray gun usage to art students at the university level. In addition, he has authored several books on painting and is a regular contributor to art magazines.

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