Polyurethane provides a protective shell that acts like a translucent shell that deflects impacts while preventing damaging water from reaching the stain. Many wood projects aren’t complete without a polyurethane coating. However, polyurethane must undergo a drying time to create a hard coating for this protective magic to work out. Perhaps you’re asking the question, how long does polyurethane take to dry?
Well, the answer to this is if it’s water-based polyurethane, it takes about 2-4 hours to dry enough to receive a second coat. Meanwhile, if it’s an oil-based polyurethane, it takes about 6-10 hours. However, after applying all the coats, it takes most polyurethane about 24-48 hours before being subjected to light.
There are different types of polyurethane, and each of them has its unique properties as well as their different drying and curing times and as much as those numbers can provide general guidelines as regards polyurethane drying times, these drying periods can also depend on various factors such as humidity level, air temperature, type of base, wood condition amongst others.
Well, you still need to follow through with this article completely for everything that needs to be known about the drying time of polyurethane. The drying time of each polyurethane type, we’ll also be reviewing each of these factors that can affect drying times.
Drying time for water-based polyurethane.
Although it takes less time for the water base to evaporate in the air than oil-based, it is still important to wait 24 hours before water-based polyurethane is hard enough to receive light trafficking.
Meanwhile, ordinarily, the drying time for water-based polyurethane is significantly less. Most of this water-based polyurethane will dry to the touch and be ready for light sanding and a second coat about 2 hours after application.
Drying time for oil-based polyurethane
It is crucial to follow the manufacturer’s instructions when it comes to the drying time of oil-based polyurethane because the drying time of each product varies. However, most oil-based polyurethanes take between 6-10 hours to dry enough and get hard to be subjected to light.
Meanwhile, many manufacturers would always suggest waiting 24 hours before subjecting oil-based polyurethane to light foot traffic. Most times, it’s safe to wait for a total of 48 hours.
This increase in drying time is because oil-based paint is generally thicker than water-based paint, and it also contains a higher amount of volatile organic compounds.
Importance of polyurethane drying time.
There are a few reasons why understanding the drying time for a polyurethane product is essential before purchasing it and when using it.
Most polyurethane usually requires at least three coats and sometimes as many as six coats to provide the protection and smooth finish that they are known for. So most of this polyurethane, especially the oil-based products, always has a window of time when the polyurethane is ready for its second coating.
Moreso, if you’re applying polyurethane to an exterior surface, you must know the time required to get dried up to ensure that rain and wind don’t ruin its surface with water or airborne debris or dirt.
However, the weather is also one factor that aids the drying time of polyurethane. Before applying any polyurethane product, be sure to have checked the weather forecast properly and ensure it is suitable enough to use the polyurethane-based on its dry time.
Also, if you apply the second coat when the first coat is yet to get dried, trust me, it’ll ruin the consistency of the first coat.
Apply the coat too late, and you’ll find out that it doesn’t adhere properly to the first coat. So you see that having a complete understanding and following the guidelines is essential as to how polyurethane drying time works.
Lastly, dry time affects the length of the overall project. An oil-based polyurethane that requires about 12 hours between costs to dry may extend the size of the project to several days more. This may be due to specific applications such as living areas in a home or main hallway.
Factors that drying times of polyurethane.
The drying times most manufacturers give are ranges of several hours, and this is because some environmental factors can affect their drying times. Let’s review some of these environmental factors and discuss how they affect drying times
While humidity can increase dry time, the temperature can also increase dry time. So it is safe to say both temperature and humidity work hand in hand in affecting dry times.
The reason why this is so is because of the higher percentage of moisture in the air. The high saturation level makes it difficult to absorb more evaporated water, extending its drying by 12 hours.
Perhaps if the humidity level is extremely high, the polyurethane may not be able to dry at all. Low humidity that is below 40 percent, in comparison, can make the polyurethane dry more quickly as the dry air absorbs the moisture from it.
So while maintaining a wet edge, it is vital to apply the polyurethane quickly to achieve a consistent coat.
When polyurethane is applied in climate-controlled buildings, its drying time is usually based on 70-degree temperatures. Meanwhile, this temperature level cannot be achieved when working in a storage shed, garage or driveway.
Higher temperature will shorten drying time as hotter air temperature will dry the chemicals or water vapor in the polyurethane more quickly. However, lower temperature, conversely, will lower the drying time as it takes a longer period for evaporation to occur.
While temperature below 65 degrees will begin to affect dry time, temperatures less than 55 degrees are too cold, resulting in the polyurethane remaining tacky indefinitely.
Polyurethane base type
The type of base type a polyurethane uses has a significant impact on its drying time, whether primer, polyurethane, paint, or stain. Water-based polyurethane may feel dry to touch in minutes after it’s an application and dry enough for a second coat in an hour or two.
Meanwhile, oil-based polyurethane will remain tacky for up to 10 hours. Oil-based coatings are longer to get dried than water-based coatings. The time it takes to complete a polyurethane project from beginning to end can be dramatically increased by this difference.
Ventilation is also one factor that can affect the dry time of polyurethane. When the room is well ventilated, the polyurethane tends to dry more quickly as the flow of air will constantly supply fresh air, absorbing more moisture from the drying polyurethane.
However, it would help if you were very careful with the ventilation. Opening a window to add moist outside air to air-conditioned dry air could get the room humidity increased and, in the process, extend the drying time.
Though using fans could be an excellent way of keeping a room ventilated, however, you should remember that they also stir up dirt and dust to fall on the surface of wet polyurethane.
Applying polyurethane to freshly sanded wood would open wood grains well suited for receiving moisture. In the process, the raw surface will allow the wood to suck in the moisture from the polyurethane, increasing the dry time significantly.
It is essential to pay attention to this as most bare unstained wood receiving polyurethane is freshly sanded. Once the fresh coat is on the un-stained wood, the wood fibers become sealed, and the subsequent coats will dry more in line with the manufacturer’s guide.
Polyurethane tends to try more quickly, depending on how saturated your wood is. Woods that are yet to dry completely would have a longer dry time as the polyurethane tends to look for blank cells to inhabit.
However, in comparison, dry wood will suck up the polyurethane more easily, hence drying faster. Meanwhile, this applies to only the first and second coats as the additional coats will adhere to the previous layer of polyurethane and get dried.
Final thought – How long does polyurethane take to dry?
Well, in the light of this, I’m convinced this post has been able to see you through some unclear situations. From this article, you can quickly tell the time duration it takes for different types of polyurethane to dry either before applying the next coat or after using all the skins and waiting for the polyurethane to be subjected to sunlight.
We were able to discuss some of the factors that impact drying times. Some of these factors, in most cases, increase the drying time duration. Also, the curing time of polyurethane was summarized in this piece. I wish you good luck with your project!