How To Speed Up Polyurethane Drying Time Quickly

The usual Polyurethane drying time

The final look of Polyurethane coating is a glossy and paint-like layer. To get such a finish, woodworkers need to apply and wait for the Polyurethane to fully form the resin layer though they could still speed up Polyurethane drying time.

The waiting time is different as there are three types of it. They are oil, water, and combination. 

The water-based one is the fastest of all. The coat can dry between 1-9 hours for brands with fast-drying substances.

Meanwhile, the oil-based one dries in 4 hours for the fastest, but the standard time for oil-based usually takes 24-48 hours.

The stated drying time refers to when you can apply another coat. To touch the layer, the drying time for water-based is 24 hours, and oil-based is 48 hours.  

Steps to speed up Polyurethane drying time

While some speed up Polyurethane drying time, others doubt the result will be similar. Don’t worry; the steps below give an instant drying process without altering the quality.

  • Choose the water-based rather than the oil-based

With not-so-different results, use water-based Polyurethane for a quick result. It has been mentioned before that an oil-based one has a long drying time.

  • Mix with thinner

Thinners like Naphtha make Polyurethane evaporates faster. As the thinner has a higher evaporating rate than turpentine or spirit, it helps the Polyurethane to dry faster.

  • Place some heat sources near 

The direct sun, hair dryers, heat lamps, space heaters, and others make liquid evaporates quickly. Place the wood near the heat source. You will get a faster drying time though the curing time is still the same.

  • Create a less humid environment

Besides heat, low humidity also makes the drying process goes faster. To create such an environment, set a dehumidifier or AC.

Factors that speed up Polyurethane drying time

After applying the steps above, there are still some conditions that influence the duration of drying. Prepare these factors best, so you can get the shortest drying and curing time.

  • The polyurethane type: though oil-based takes longer, some types require less time, like Minwax high-build polyurethane. It is because the high-build ones need less coating. For water-based, rust-oleum varathane Polyurethane dries in two hours.
  • The drying system: instead of waiting for the Polyurethane to dry naturally, set the drying system that involves the best condition to speed up Polyurethane drying time (explained below) with tools like heaters, dehumidifiers, hair-dryers, heat lamps, or fans. 
  • The additional ingredients: some brands add extra solvents, stains, natural oils, or add-in drying agents. Each addition affects the drying time, whether it speeds up or slows down.
  • The wood and its surface: woods containing more oil are hard to absorb Polyurethane and dry slower. Moreover, the surface’s conditions, like its cleanness, rawness, being sanded or not, also influence the drying process. Raw wood with a clean sanded surface dries fastest.

The best condition to speed up Polyurethane drying time

Another way to accelerate the drying process is to prepare the best condition for the wood. The ideal condition includes temperature, humidity, and ventilation.

Firstly, just like any other liquid, Polyurethane will evaporate and dry quickly in a high-temperature environment that should be 26-35 Celsius or 79-95 Fahrenheit.

Though the sun provides warm temperatures, its UV rays damage the wood because Polyurethane is not UV resistant.

Then, the ventilation influences the airflow and humidity. A less humid room with good air circulation can speed up the polyurethane drying time and reduce the odor problem.

You can also use the tools mentioned before or simply let the windows open. 

Why you should speed up Polyurethane drying time

Everyone might have his/her answer to the question above. Some may have a certain deadline to finish the wood. Yet, longer drying time brings more risks to the wood.

During the long drying process, dust or other unwanted things could damage the surface. The long drying time also signifies something wrong during the application process or even in the wood.

Hence, the woodworkers need to speed up Polyurethane drying time to fix the condition. 

Things to avoid when you speed up Polyurethane drying time 

  • Overheating: setting an extreme temperature above the normal room temperature could cause a fire. So, set the normal temperature or raise it just above the normal.
  • Adding certain thinners or Naphtha: liquid with volatile and flammable hydrocarbon mixture should not be mixed with Polyurethane as they are prone to fire hazards.
  • Excessive coatings: for each layer, just add a normal stroke to the surface. Not only is it good to speed up Polyurethane drying time, but it also gives a neat finish look.
  • Leave the wood in an open space: at least there are two major damages to wood: dust and UV rays. Dust sticking to the surface makes it bumpy, and some pinholes from bubbles might also appear. Furthermore, UV rays damage the wood to the grain. 

Causes of the longer Polyurethane drying time

Some speed up the drying process because their woods are not drying. The causes may be:

  • Too thick coats
  • Cold weather or low room temperature
  • Humid environment
  • Limited air movement
  • Not knowing the type of Polyurethane that you use
  • Expired Polyurethane
  • The wood types

All the mentioned causes could be prevented by checking and preparing before the application. Another possible cause is impatience feeling.

When the first coat has not been set yet, but you have already applied another, the second will take forever to dry. Despite external factors that you cannot control, you should control yourself when applying Polyurethane.   

How to fix the not-drying Polyurethane

When you are suspicious of your Polyurethane, you first need to check the polyurethane type and its usual drying time.

Once you are sure and find it is past its drying time, figure out the cause. Fix the problem and then apply the steps to speed up the Polyurethane drying time above.

Fixing might result in less quality furniture, so double-checking and preparing beforehand are more suggested.

While you apply the steps and tips above, please be aware that drying too quickly or an insufficient drying process could also cause cracking.  

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