How To Spray Polyurethane With Wagner HVLP & Airless Sprayer?

Did you feel disappointed when you noticed brush marks or roller fibres on your final coat of polyurethane even after you applied a perfect finish? And you may wonder, as the spraying paint gives a lovely, smooth finish, will it work similarly to polyurethane? Therefore, a natural question would be, How to spray polyurethane?

A polyurethane layer is a liquid plastic that, once dry, forms a tough and durable layer that can protect various surfaces, like a polyurethane coating that protects wood from moisture damage. Therefore, if you have decided to spray polyurethane for your upcoming project, check out our complete guide below!

Can you spray polyurethane with a spray gun?

how to thin polyurethane for spraying

Yes, It is easier to spray polyurethane since it requires no precise technique. Using a paint sprayer to spray polyurethane delivers a beautiful finish coat that adds beauty to everything from floors to furniture and cabinets. Also, it can add durability to any wooden surface.

Most commonly, you will be looking for an Airless spray gun, an HVLP sprayer, or a conventional spray gun. An airless sprayer is the best option when it comes to the highest production. An HVLP spray gun will save you money and help to apply polyurethanes or other thinner coatings well.

Plus, conventional spray guns are usually the most cost-effective method of spraying polyurethanes or paint.

Check out this guide to learn if an HVLP, Airless sprayer, or pump sprayer suits your upcoming project. Furthermore, you may want to consider how you feed the spray gun with materials.

Note: Simply read the instructions and thin the paint accurately for spraying polyurethanes with pump sprayers.

Among the most common options are pressure and gravity guns. The heavier body coating of polyurethane may require a pressure-fed spray gun. However, spraying polyurethane requires a few extra steps but will result in a more attractive finish and fewer mistakes.

The best way to spray polyurethane is presented in this step-by-step guide. We’ll cover the preparation and application steps throughout this process, so there’s no need to worry about spraying polyurethane.

1- Choosing The Right Sprayable Polyurethane

You should consider several factors when choosing spray polyurethane for your project. The kind of spray you select will affect the drying time and the final result.

Both types of polyurethane offer good looks and are excellent in their way, but they have different advantages and properties. So it is essential to decide whether to use an oil-based polyurethane or water-based polyurethane spray.

You can spray oil-based polyurethane like Minwax polyurethane and water-based polyurethane like Varathane polyurethane.

Choosing Oil-Based Polyurethane versus Water-Based Polyurethane

* Can You Spray Water based Polyurethane?

No doubt, Water-based poly tends to be more transparent than oil-based polyurethane. Water-based poly produces fewer toxic fumes and volatile organic compounds than oil-based polyurethane, making them better for the environment. However, water-based polyurethanes are less durable than oil-based polyurethane.

* Can You Spray Oil based Polyurethane?

Yes, DIY furniture looks more beautiful when coated with oil-based polyurethane, which is not the case with water-based polyurethane. Also, you can spray polyurethane for wood. Water-based polyurethanes are best for lighter woods, while oil-based ones generally enhance the color of darker woods.

2- Spray Polyurethane Dry Time

Water-based polyurethanes dry faster than oil-based polyurethanes, so you should choose the ones that suit your work best depending on your needs and preference. Water-based Polyurethane sprays take two hours to dry, and they can be recoated and cleaned with water whereas you will need five to twelve hours for oil-based polyurethane to dry completely.

Even with fast-drying oil-based ones, the fastest it takes is four hours. You only have one choice if you have short of time and need to complete your project quickly.

3- Finishing Touch

When it comes to the finishing look of your polyurethane coating, you have to choose between a water-based or oil-based spray. Polyurethanes based on water are thinner and, as a result, require more coats whereas oil-based polyurethanes require fewer coats because of their thicker consistency for finishing.

Thus, the finishing effect of oil-based polyurethane is better than Water-based polyurethanes.

4- Work Environment

The two types of Polyurethanes require special working conditions for optimum performance. Water-based polyurethane dries fast so that you can use it anywhere. On the other hand, you should use oil-based polyurethanes in a clean environment because they may take time to dry.

In case, when oil-based polyurethane is not used in a clean environment, insects and dust will stick to the surface over time and reduce the quality of the finish.

5- A Final Touch-Up

A water-based polyurethane usually requires two or three touch-ups after spraying. So, it is necessary to give a second coat to the surface once it has dried to achieve a good finish that eventually improves the surface’s quality.

However, oil-based polyurethanes perform best in this area. With its first coat, oil-based polyurethanes give the surface a nice shine and appearance and do not require additional coats to provide protection.

6- Cost-effective

The most important consideration is cost. Oil-based poly will be less expensive than water-based poly. Thus, if you are concerned about your budget, it is best to try oil-based polyurethanes.

How to Spray Polyurethane?

Can you use a paint sprayer for polyurethane?

This step-by-step guide will be beneficial when spraying polyurethane paint for wooden or other surfaces. Take note of the following steps before proceeding.

1- Prepare Your Work Area

Organizing your work area should be your first concern. Make sure that the working room is clean before beginning your work. It is necessary to spray the material or any surface in a clean space. Furthermore, keep all the things you need for spraying within reach, but not too close.

2- Sand The Surface

Preparing the surface on which you will spray the polyurethane paint is another important step after setting up the working area. You should have a clean, dirt-free surface. If necessary, wipe the surface with a clean cloth before spraying. Moreover, sand the project surface before applying any stain or polyurethane to get a quality finish.

3- Setting Up The Sprayer

Spraying polyurethane in the right amount is the key to success for your project. In this regard, you need a quality sprayer with an adjustable knob that allows the controlled amount of product to flow through the paint sprayer. Plus, it would be a bonus if the paint sprayer came with multiple spray tips.


It’s a good idea to test the amount of spray on a drop cloth or cardboard box first, and then adjust the dial until it is as you want it.

4- Thinning Polyurethane To Spray

Sprayable polyurethane must be appropriately prepared before starting spraying. The thicker coats of polyurethane may require thinners to make it easier to spray. If you are unsure whether you need a thinner or skip this thinning step, then apply the paint without adding thinner and see if you like the final results.

For this purpose, if you notice large clots or an orange peel effect after spraying the material without thinner, you may want to either add thinner or try a slightly higher air pressure setting.

*What is the right amount of thinning for spraying polyurethane?

Polyurethane needs to be at least 10% thinner before spraying. Adding thinner is usually determined by referring to the coatings technical data sheet, which will list appropriate thinners or cleaners that you can often use for thinning purposes.

5- A Cleaning And Drying Process

Let your paint dry. After the paint has dried, clean the painted surface with water.

Spray polyurethane vs. brush on

If you apply poly using a paintbrush, you will quickly see the delicate lines left by the brush bristles. So, if you want to apply a second layer of polyurethane, you must sand it lightly to remove brush strokes, dust it thoroughly, and sand it again.

Plus, the brush needs to have the perfect angle and be high-quality. With each poly application, you’ll need a feather-light touch to make your brush strokes less noticeable. Polyurethane can be applied without brush strokes using a paint sprayer.

Additionally, you can apply lighter coatings with Wagner sprayers or Airless sprayers so that each layer dries much faster.

Best Way To Spray Polyurethane Finish

It is also essential to use good techniques to get a good finish. Consider your application technique, equipment, polyurethane characteristics, and where you spray to ensure that your coat is applied efficiently and looks better.

When spraying polyurethane, you should aim to apply thin coats for the best results. To get a smooth finish, smaller spraying fluid nozzles 1.0 – 1.4 mm typically or air assist airless tip sizes are needed.

For spray guns, you will generally hold the gun closer to the product surface, while air assists airless spray guns need to be held farther away.

It is recommended to sand between each coat of polyurethane (usually with about 220 Grit sandpaper) as this will help create a surface that will adhere to the next.

If you want polyurethane to be protective, you should increase its thickness through multiple thin coats.

How to spray water-based polyurethane?

There are some benefits of switching from solvent-based polyurethane to water-based polyurethane, such as a lower fire hazard and odor and minimal environmental impact. This change cannot be easy since water-based polyurethane is challenging to apply.

Although we have found that pulling the release on the gun and covering the area while moving the gun is pretty similar, some distinct differences can create problems that are potential barriers to switching. Thus, we have provided all the solutions to your issues below:

  • Before you start spraying, you need to be careful not to stain the surface.
  • In cold weather, water-based coatings don’t atomize as efficiently. For this reason, you can use air-assisted airless and airless sprayers.
  • A water-based coating can even be thinned with water to improve atomization.
  • A major challenge in converting to water-based finishes is cleaning the spray guns and equipment, and it is best to disassemble your guns and scrub every part with a brush afterward. Plus, Spray gun manufacturers often sell a gun-cleaning solvent.

Tips to spray polyurethane with HVLP Wagner or Airless Sprayer

The process of spraying polyurethane can be fast and easy, but it can also be painful if you don’t know how to handle it properly. So, following are some tips for ensuring a smooth finish:

  • Make sure not to get drips and runs on vertical surfaces when you are applying polyurethane.
  • Do not spray more than one thin coat until it is completely dry.
  • In case of runs, use a sharp razor blade to remove them gently.
  • Be sure to spray in clear light, so you don’t overspray or miss any areas of the piece.
  • Before you begin, prepare all your safety and cleaning tools.

Conclusion on How to Spray Polyurethane!

All in all, we are hopeful that the topic How to spray polyurethane is now crystal clear to you. Also, you can ensure that your coating will apply efficiently and look better by considering your application equipment, technique, where you spray, and the properties of the polyurethane you want to use. Now, you all know that a good way of achieving a professional-looking finish on wooden surfaces is to spray polyurethane.
Good Luck!

FAQs on How To Spray Polyurethane?

Can polyurethane be sprayed?

Yes, Absolutely. Polyurethane spray finish is durable and attractive, and it looks great on all wooden surfaces, from furniture to floors. There are numerous spray polyurethanes available in which spray cans and paint sprayers are the most popular ways to apply polyurethane.

Do you need thinning polyurethane to spray?

The polyurethane coating possesses long-lasting durability, meaning the liquid itself is pretty thick and honey-like. So, a thinner will be necessary before spraying your polyurethane. It is best to start by testing the polyurethane without thinner to see how it feels, then add thinner if needed. In short, The thinner the polyurethane, the better the finish.

How to thin polyurethane for spraying?

It is necessary to mix oil-based poly with paint thinner, whereas water-based poly is mixed with water. You can make the base coat by mixing two parts polyurethane with one part paint thinner. Turpentine, paint thinner, mineral spirits, and even water works well for thinning polyurethane. Painters often use turpentine, a strong-smelling substance, to thin polyurethane.

What pressure are you using to spray polyurethane?

The spray pressure for the base coat should be between 26-29 PSI. Also, It’s nice to spray a clear coat at a 2-3 psi pressure to get better atomization and flow out.

Can airless sprayers be used for polyurethane?

The majority of paint sprayers can be used with polyurethane, including airless sprayers. Make sure to clean the sprayer thoroughly before and after use, and you should use the correct viscosity of polyurethane.

Is it possible to spray polyurethane with a pump sprayer?

You can spray polyurethane with pump sprayers. Applying a thin coat of polyurethane (as thin as possible) will give you the best finish. It means using smaller fluid nozzles (1-1.4mm) or making a quick pass over the surface of the product. 

Meet Your Hola Paints Author

Jennifer is an experienced professional working with paint sprayers, painting tools, and other supplies. She provides valuable painting tips for visitors according to her experience.