When you are planning a new project, it is crucial to get the timing right, or it could cost you money and your reputation. After all, nobody wants to be the contractor who promises to deliver a piece in a few days, only to show up a month later.
One thing that causes delays is underestimating dry times. When someone asks, “how long does polyurethane take to dry?” they usually want to know how long it takes to cure.
What is the difference? Keep reading to find out.
How Long Does it Take for Polyurethane to Dry?
It takes anywhere from 2 hours to 24 hours for the polyurethane to dry, depending on the type of polyurethane you use. However, polyurethane needs at least 3 weeks to cure fully. While some water-based polyurethanes dry and cure in 3 days, estimating the project duration for another couple of weeks is better.
What is the Difference Between Drying and Curing Time of Polyurethane?
Drying time is the period between coats of polyurethane, while the curing time is when the wooden surface is ready for use.
When polyurethane dries, it means it has stopped being tacky and is now dry to the touch. You can then apply another coat or more as required.
After the final coat has dried, you can walk on the surface with socks on, but you shouldn’t put heavy things on it as it isn’t yet strong enough to support a lot of pressure.
You also shouldn’t spill any liquid on it, or it will seep through to the wood, and you’ll have to start all over. In other words, it is not yet durable, water-proof, or useful.
The drying time varies for polyurethane in the manner below:
- Water-based polyurethane can dry in as little as 1 hour.
- Oil-based Polyurethane takes at least 4 hours for fast drying formulae.
In comparison, other primers need 12-24 hours to reach the drying stage.
How Long Does Polyurethane Take To Cure
When the polyurethane is cured, it means that it has dried completely. You now have the finished product that will support your furniture, handle foot traffic and withstand scratches for the next few years with ease.
The curing time is as follows:
- Water-based polyurethane takes 3 days to 21 days.
- Oil-based Polyurethane lasts for 21 and 30 days.
Brands such as General Finishes recommend that you wait the full 21 days after applying the final coat of the water-based topcoats before active use.
We’ve created a polyurethane cure timetable so that you don’t lose your patience, as some might take up to a month, depending on the prevailing weather conditions.
|Water-based Poly||Oil-based Poly|
|Time between coats||8 hours||24 hous|
|Dry to touch||24 hours||48 hours|
|Ready to place things||2 days plus||4 days plus|
|Completely Cured||20 days||30 days|
Factors that Affect the Drying of Polyurethane
Several factors affect how soon polyurethane dries. They range from the base it’s made of to the conditions they are applied under. Some of these factors are:
1. Type of polyurethane
There are two major types of polyurethane going by their base composition, and they affect their drying time. They are:
a). Oil-based polyurethane: this type of polyurethane uses petroleum products and mineral solvents as the base, making it quite thick and durable.
Oil Based Polyurethane Drying Time
Oil-based polyurethane takes anywhere from 4 hours to 24 hours to dry, depending on the formula. It requires at least 30 days to cure fully. Fast-drying polyurethane might cure in 21 days, but weather conditions might delay it.
b). Water-based polyurethane: as the name suggests, this type of polyurethane is mainly comprised of water. The result is you get thinner and lighter coats than oil, which means it also evaporates or dries quicker.
Water based Polyurethane Drying Time
Water-based polyurethane is dry and ready for the next coat in 2 hours in optimal conditions. It can also fully cure in 3 days, but so many factors can delay this process, so you should estimate at least 3 weeks.
It is always better to finish a project ahead of time than to ask for more time. Don’t you agree? Moving on…
2. The Temperature
The second most important factor that influences how quickly polyurethane dries and cures is heat, or we could say the temperature.
The ideal temperature for polyurethane to dry is between 70 – 77 degrees Fahrenheit. If the temperature is much lower than this, it can extend the drying time by a few hours or even a few days.
That is why most manufacturers tell you the optimum temperature for applying the finish. If the temperature is in the mid-50s, they might tell you not to even bother applying it at all.
What about high temperatures? Higher temperatures will make the poly dry quicker, but that isn’t necessarily a good thing. It might crack if the outer surface dries too fast, which might even be worse than a slow drying time.
When you apply polyurethanes and other coverings on wood, it is good practice to keep the windows shut so that dust doesn’t enter. However, given the strong odors from some finishes, mainly oil-based polyurethane, you should leave the windows open.
You also need adequate ventilation for the polyurethane to dry on time. Yes, there is the risk that the dust might come flying back in. If that happens, sand the coat and apply it again.
A fan is an excellent way to boost ventilation without risking as much dust. In my experience, this has rarely been a problem. As long as it isn’t a windy day, you should be okay.
Here is another essential factor, and this goes hand in hand with the temperature. The ideal humidity for water-based polyurethane to dry is 50% and 70% for oil-based polyurethane. Of course, brands and products differ.
However, what is consistent is that when it is too humid, the polyurethane will take much longer to dry, and the opposite is also true.
Now, you’re probably concerned that high temperatures in the summer also mean high humidity in some areas, and you’re right.
In that case, you can control the indoor quality using three devices:
- A humidifier
- HVAC system
You probably need these devices in your home anyway, so this shouldn’t add to the project’s cost of the project. But if you don’t want to buy them, wait for better weather conditions.
5. The Thickness of the Coat
The rule when applying polyurethanes is to always use thin coats. Thin coats dry faster and more evenly. Plus, they are easier to amend if there is a problem.
When the coat is too thick, it will take considerably longer for the polyurethane to dry. You need to be patient and not try to enhance it using a blow-dryer, or the inner coat might cake.
That is why many professionals often advise against triple-thick poly or one coat poly. Even though they often claim to dry quickly, they rarely do.
Polyurethane can be brushed on, sprayed on, or wiped on. If you choose a method that does not allow you to control the amount you’re applying properly, you could end up putting too much, which slows the process.
When you use a spray or wipe-on poly, the finish will dry much quicker than when you use a brush or a roller. That is because the coats are thinner and lighter with the former application methods.
7. The Type of Sheen
There are four main types of sheen, from lowest to highest:
- Matte (labeled as flat)
- Gloss (sometimes referred as high gloss)
Glossier finishes take marginally longer to dry for both types of polyurethane.
8. Condition of the Wood
Polyurethane dries faster on raw wood. If there is already a finish on it, it will take much longer to dry, especially if you are applying a water-based poly over an oil-based product or vice versa.
If you applied a stain and it hasn’t cured, it will also delay the drying time of the polyurethane.
Oil-based polyurethane is dry when you can no longer smell it, and the surface is no longer tacky. Water-based polyurethane is dry when the surface is not cold to the touch. At this point, you can apply the next coat (after sanding, of course) and then repeat the process.
How well you sand the wood may also affect the drying time, especially if it was previously finished.
9. The Formula of the Finish
Finally, the most important factor that determines the drying and curing time of polyurethane is the actual product you are using.
- Fast-drying variants of oil-based polyurethane dry in a third or even a sixth of the time it takes regular oil-based finishes.
- Fast-drying formulae with water-based polyurethane tend to half the time.
While there are pros and cons to using the speedy alternatives, this is definitely a significant advantage to consider when planning your next project.
How to Speed Up Polyurethane Drying Time?
The four most reliable ways of making polyurethane to dry faster without damaging the product are:
- Increasing the temperature (70 degrees Fahrenheit is ideal )
- Lowering humidity by opening windows
- Applying thin layers
- Preparing the surface properly before application
If you are using a fast-drying alternative, don’t attempt to speed up the drying time unless it is taking much longer than advertised. Otherwise, you might just ruin the coat, and you’ll have to start all over.
How long does it take for water-based polyurethane to dry on hardwood floors?
Water-based polyurethane can dry on hardwood floors in as little as 4 hours. After this, you may walk on the floor with socks. Within three days you can start moving furniture back on it. However, it may take up to 21 days for water-based polyurethane to fully cure.
How long does it take for Minwax polyurethane to dry?
The fastest drying oil-based Minwax polyurethane is dry in as little as 4 hours, while the quickest water-based polyurethane is dry in 2 hours. Even the Minwax One Coat dries in just 2 hours.
How long does polyurethane take to dry on wooden furniture?
With proper ventilation and the right weather conditions, polyurethane will dry on wooden furniture in as little as 2 hours. The curing time is much longer at 21 days for water-based poly and 30 days for oil-based polyurethane.
How long does spray polyurethane take to dry?
Within 2 hours of application, spray polyurethane is dry to the touch. At this point, you can add another coat. You would need to wait overnight before it will be ready for light use, and at least 3 days before it has fully cured.
How long does Varathane polyurethane take to dry?
The fastest drying Varathane polyurethane takes 2 hours to dry. When applied with an aerosol, it can be dry in just 30 minutes. The surface will be dry enough for light use after 24 hours and will be cured enough for normal use in 3 days.
When can you walk on polyurethane wood floors?
When using water-based or fast-drying oil-based finish, you can walk on polyurethane wood floors with socks in 24 hours. After 7 days you can put heavy things on polyurethane wood floors.
Always Wait for Polyurethane to Dry and Cure
As you have seen, there is a vast difference between drying times and curing times. Answering the question ‘how long does polyurethane take to dry?’ is complicated because the user just might mean curing time.
Many factors affect drying times, so be sure to get conditions as close to optimal as possible.
While water-based polyurethane dries quickly, it takes almost as long as oil-based polyurethane to fully cure.
Now that you know all of this, it’s time to put it to the test. But first, you might want to read our article on how to apply polyurethane to stains.