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Can I Use Paint Sprayer To Spray Polyurethane?

Just when you thought the polyurethane you used added a nice coat to you, only to find brush marks or roller fibers on the last coat.

So, it's natural to ask, "Can I spray urethane with an airbrush??" After all, spray painting not only gives it a gorgeous, smooth finish but also saves a lot of time and paint usage, so why not do the same with urethane?

This is an excellent question, and one I'm going to answer now, but with an extended caveat.

Yes, you can spray polyurethane with a spray gun. Spraying urethane to make it smooth and streak-free is difficult to achieve with a brush or roller, however, not every type of urethane can be sprayed.

Be sure to read the directions before buying your unused polyurethane.

Why can use paint sprayer to spray polyurethane?

Water-based polyurethane and oil-based polyurethane

Polyurethane produces a smooth, gorgeous finish when sprayed, but using the wrong one can produce sub-optimal results. While water-based and oil-based polyurethanes do the same thing, they have some unique properties that you need to consider.

1. Color

The first thing you need to notice is how different they look. In the jar, the oil-based polyester looks yellow, while the water-based polyurethane spray looks creamy. Oil-based polyurethane is amber in color when dry and darkens over time. Water-based polyurethane, on the other hand, dries crystal clear and stays clear for the rest of its life.

For such a choice, it comes down to personal preference. Oil-based polyester is excellent if you prefer darker, more lively shades. However, if you want to keep the wood's color intact, stick to water-based polyurethane.

2. Drying time

While spray urethane dries faster than brushing or rolling, the wait time for oil-based urethane is still a nightmare. On average, you will need to wait 5 to 12 hours for the oil-based urethane to be ready for the second and third coats.

After the waterborne polyurethane dries, it can be reapplied under favorable conditions in 2 hours or less. It takes 4 hours even if you are using an oil based quick drying product.

If you're in a hurry and want to finish your project in a day, you only have one option.

3. VOCs and Toxicity

Spray polyurethanes are made from isocyanates, which emit toxic volatile organic compounds (VOCs). This toxicity is exacerbated when sprayed.

While both types emit VOCs, the levels in oil-based polyurethanes are much higher. This is because the chemicals required to make oil-based polyurethanes contain high levels of VOC-containing chemicals.

Therefore, extreme care needs to be taken when spraying polyurethane. Keep away from any children, pets or anyone with breathing difficulties in a ventilated area.

4. Clean up

Another factor to consider is how easy it is to clean the tool when you're done. Waterborne polyurethane spray can be diluted and cleaned with water and a spray gun cleaner. This makes it easy (and cheap) to clean up any mess in the process, which can help you save time even further.

Oil-based polyurethanes are diluted and cleaned with mineral spirits. As you might expect, this takes more time and a higher difficulty.

5. Cost

This won't affect your product's prospects, but it will affect your expectations. When you spend a lot on the finish, you want it to be worth it.

While oil-based urethane is less expensive and water-based urethane is more expensive, it does save time on your project and cleaning supplies are cheaper.