How Long Does It Take For Polyurethane To Dry? (Cure Time)

When working with polyurethane, you want to ensure that you do the job right the first time. This can be tricky to do, especially if you are short on time and cash. How long does polyurethane take to dry? Check out our tips to avoid mistakes while working. 

Polyurethane is a plastic material invented in the 1930s by Dr. Otto Bayer. It creates a translucent protective coat on application that repels water and impact. Depending on the formula, you can use it to make insulation, cushioning, coatings, shoe soles, and sportswear.  

How Long Does It Take For Polyurethane To Dry

Water-Based Polyurethane Dry Time  

How long does water-based polyurethane take to dry? Water-based polyurethane typically takes between one and six hours to dry, depending on the brand and formula. At this point, you can sand it and add a second coat. This level of dryness means the layer is no longer tacky and wet but is not yet durable or waterproof. 

Water-Based Polyurethane Cure Time  

How long does polyurethane take to cure? The cure time refers to the amount of time it takes for the polyurethane to reach its maximum hardness. You can still use the covered object to varying degrees but will need to exercise some level of care until the cure period is over. Depending on the brand and formula, water-based polyurethane can take between three and 30 days to cure. 

Oil Based Polyurethane Dry Time 

How long does oil-based polyurethane take to dry? The dry time for oil-based polyurethane varies depending on the brand and formula. Experts estimate that oil-based polyurethane takes 4-10 hours to dry for a full coat but try to wait 24-48 hours for light use. It typically takes longer than water-based formulas to dry as there are more VOCs in the mixture, and the formulas are thicker than water-based polyurethane.  

Oil Based Polyurethane Cure Time 

As with the water-based mixtures, the cure time for oil-based polyurethane is extended when compared with its drying time. Overall, it is recommended that you wait 30 days at most for the layers to reach maximum hardness. We suggest preventing contact with rugs, water, and cleaners until then. 

How Long to Let Polyurethane Dry Between Coats?  

Need to know how long to let polyurethane dry between coats? You will need between three and six coats per project, depending on your needs, formula, and external conditions. This means that it could take between 6- and 60-hours total for the project to dry; this time sounds lengthy but is vital for effective application. 

Why is it important to wait for each coat to dry properly? Applying a second coat too early could ruin the finish of the final product but waiting too long and not sanding well could prevent adhesion to the previous coat. Ruining the surface means restarting from the beginning, wasting time and money. Other things that could ruin your project’s finish if not monitored include dirt, debris, rain, shoes, furniture, and cleaners. 

brown wooden board

Factors Affecting The Drying Time Of Polyurethane 

There is a complex mix of factors that affect how long it takes polyurethane to dry.  

  • 1
    Temperature  
    The times suggested by brands are based on 70 degrees Fahrenheit. As a rule, the higher the temperature surrounding the drying item, the faster the particles evaporate, but too high temperatures could cause the coating to crack as it dries too fast. The lower the temperature is, the slower it will dry; 55 degrees or less will leave your project tacky indefinitely.
  • 2
    Humidity  
    The higher the humidity, the slower the piece will dry. Low humidity conditions suck the water out of the polyurethane; in 40 percent or less humidity, apply each layer fast for an even coat. As a rule, ideal water-based humidity levels are around 50 percent, and oil-based polyurethane is around 70 percent. 
  • 3
    Polyurethane Type  
    Each type of polyurethane has differing formulas and VOC levels. This heavily affects the drying time of each layer, impacting your overall project length. 
  • 4
    Coat Thickness  
    As with paint, how thick each layer is will affect how long the project takes the dry; the thinner, the better if you are on a time limit. Again, the key is using even strokes and minimal layer thickness.  

How To Make The Polyurethane Dry Faster? (Speeding Up Tips) 

  • Apply Heat 
    As we briefly mentioned above, heat is a key element in drying polyurethane properly. Increasing the temperature of the room using radiators, space heaters, heat lamps, or hairdryers could help speed things up. Using polyurethane on a warm day is a natural and easy way to speed the process up. 
  • Dehumidifier 
    Dehumidifiers remove moisture from the air, which helps suck moisture from each layer. Low humidity days do the same thing without using electricity or batteries but be wary of our tips above. 
  • Ventilation 
    Opening the windows, using a fan, or using your home’s AC system could help increase airflow and decrease the drying time of your project. 
  • Thin layers 
    Coating your object in thin layers means that there are fewer particles that need to evaporate, decreasing the overall dry time. 

Frequently Asked Polyurethane Drying Time Questions 

How do you know when polyurethane is dry? 

As a rule, polyurethane is dry when it is no longer tacky and wet. More specifically, oil-based polyurethane is dry when it is non-tacky and you cannot smell it anymore. On the other hand, water-based formulas will no longer be cold to the touch in addition to no tacky or wet spots. 


What happens if you don't sand between coats of polyurethane? 

For some types of polyurethane, nothing happens if you do not sand between coats. For most formulas, however, most types will not adhere properly and may peel off or deform over time. Therefore, please read the label of your chosen one thoroughly before purchasing to ensure you know which type it is. 



Conclusion

How fast does polyurethane dry? Now you know exactly what goes into the drying and curing times of polyurethane; take these tips on board to avoid mistakes and get it right the first time. 


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