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 it 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 final coat on application that repels water and impact.
Depending on the formula, you can use it to make insulation, cushioning, polyurethane coating, shoe soles, and sportswear.
Water-Based Polyurethane Dry Time
How long does water-based polyurethane take to dry? Water-based polyurethane tend to take between one and six hours to dry first coat, depending on the brand and formula.
At this point, you can sand it and add a second coat or third coat. This level of dryness means the layer is no longer tacky and wet but is not yet durable or waterproof.
Polyurethane wood floors like rose wood surface or durable matte surface or aromatic cedar may cause project delays due to their natural oils that slow the process. Dried polyurethane can still easily get damaged or wrinkled by too much pressure.
Water-Based Polyurethane Cure Time Table
How long does it take to cure properly? The cure time refers to the amount of time it takes for the water based polyurethane varnish to reach its maximum hardness. Polyurethane varnishes come in three different types of sheen.
You can still use the covered object to varying degrees, but will need to exercise some level of care until the curing process period is over.
Depending on the brand and formula, water-based polyurethanes can take between three and 30 days or about a month to fully cured.
Oil Based Polyurethane Dry Time
How long does oil-based polyurethanes take to dry? The dry time for oil-based polyurethanes varies depending on the brand and formula. Experts estimate that oil-based polyurethane varnish takes 4-10 hours to dry for a full polyurethane 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.
Remember to wear proper protective equipment to avoid contact with volatile organic compounds.
Oil Based Polyurethanes Cure Time
As with the water-based mixtures, the cure time for oil-based polyurethane or oil based poly 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.
Curing is a more thorough process where the polyurethane completely hardens throughout. This is when the polyurethane has been completely exposed to oxygen and has gone through a complete chemical reaction with the oxygen.
How Long to Let Polyurethane Dry Between Coats?
Need to know how long to let minwax polyurethane dry between coats? You will need between three and six coats per project, depending on your needs, how many coats, 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 subsequent finishing processes of subsequent coats of the final product, but waiting too long and not sanding well could prevent adhesion to the previous coat.
Ruining the finished surface (polyurethane 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, wear shoes, sanded wood furniture, and cleaners.
Rough treatment can result in wrinkles in the finish or other surface blemishes, because the varnish underneath the surface is not yet “cured.”
Factors Affecting The polyurethane drying times
When you applying polyurethane to the hardwood floor with foam brush or sprayer, you're applying a layer of semi gloss polyurethane resin in a liquid solvent, to the hardwood floors. There is a complex mix of factors affecting polyurethane drying time, how long it takes polyurethane to dry.
- 1Temperature
The times suggested by brands are based on 70 degrees Fahrenheit. As a rule, the higher the air temperature surrounding the drying item, the faster the particles evaporate, but too higher temperatures could cause the polyurethane coatings to crack as polyurethane dries too fast. The lower the temperature is, the slower it will polyurethane to dry; 55 degrees or less will leave your project tacky indefinitely. - 2Humidity
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 (high humidity), and oil-based polyurethane is around 70 percent. - 3Polyurethane 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. - 4Coat Thickness
As with paint, how thick thinner layers will affect how long the project takes the polyurethane to 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)
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 spray polyurethane, nothing happens if you do not sand between multiple coats. For most formulas, however, most types will not adhere properly and may peel off or deform over time.
Conclusion
How fast does polyurethane dry? Now you know exactly what goes into the polyurethane drying time and curing time; take these tips on board to avoid mistakes and get it right the first time.