What Happens If You Put The Second Coat Of Polyurethane Without Sanding?

Sanding plays a vital role in the finishing process of the woodworking industry. Many woodworking and DIYers hobbyists sand for a variety of reasons. It could help smooth the surface or scuff it for various projects such as staining.

So, what happens if you put the second coat of polyurethane without sanding? 

What Happens If You Put The Second Coat Of Polyurethane Without Sanding?


The absence of sanding between polyurethane coats has no discernible effect on the finish. It would be better to sand polyurethane coats in between to help enhance adhesion among the layers and give an overall level of finish.

When you’re working on a tight deadline and don’t have time to sand, spread thin layers of polyurethane formula over the floors’ surface and let it dry before proceeding to the subsequent coats. 

If you are using a water-based poly product, allow it to fully cure for at least 6 hours before moving onto the next coat.

With the application of oil-based polyurethane, you must wait at least an entire day for the previous layer to dry before adding the next layer. Then, apply two or three coats of polyurethane to the surface.

Can You Add Too Many Coats of Polyurethane to Your Floors?

You can, however, apply many more polyurethane coats to the surface of your floor. However, based on our extensive experience in the woodworking industry, adding more coats of polyurethane formula leads to more cons than pros.

In general, many woodworkers consider the application of more than three layers of polyurethane substance “more.” Except for the fact that it is expensive, it makes no difference. Adding too many coats will incur additional costs in terms of acquiring larger quantities of the formula.


Extra polyurethane coats would necessitate sanding between layers, which can be time-consuming, especially if you have more than three coats, and waiting for them all to dry is a must.

Another disadvantage of applying multiple coats is that poly tends to become gooey and thick and, as a result, will likely flake off within a short period.

Commonly, the application of several layers of polyurethane tends to make oxidation relatively high. Hence, your surface’s hue will turn yellow more quickly than usual, especially if you choose to use poly products that contain oil-based polyurethane.

Typically, two polyurethane layers would suffice, especially if you work on projects with a tight budget. Try applying three coats for the best results on your surfaces.

Further watching: The Secret To One Coat Polyurethanes

What Is The Secret To Getting A Perfect Polyurethane Finish Without Sanding? 

The key reason for sanding between layers is to stack out brushstrokes or drip marks before applying a second or third coat of polyurethane.

If there is any apparent unevenness between layers, you should sand. However, you can use a foam brush to avoid brushstrokes in your polyurethane. Combining foam rollers and foam brushes helps make it way easier to apply and clean up after the project. 


If you use that brush, you won’t have to worry about sanding between polyurethane coats. In addition, oil-based polyurethane levels out brushstrokes better than water-based polyurethane. The reason is oil-based products dry slower; therefore, they have more time to level out.

Frequently Asked Questions

Can You Apply Polyurethane Over Stain?


Yes, the application of the polyurethane formula can be possible over the stain. Oil-based stains and water-based polyurethanes, on the other hand, do not mix well. 

As a result, if you want to put a water-based poly product over the stain’s surface, you should do the sanding step first. To etch the surface, you can work with rough sandpaper and wood sanders. Steel wool can also be an alternative.

Do You Sand After The Last Coat of Polyurethane? 

The final coat should not need sanding. Instead, you add the final coat, allow it to cure fully, and finish the work. But if you plan to sand and rub out the final finish, you may probably remove the majority of the satin-containing surface, which eventually brings in a glossy finish.

Can You Apply Polyurethane Over Old Polyurethane?


Yes, if you have properly prepped the finish, you can recoat your hardwood with a polyurethane finish. You can use a heavy floor buffer, then gently sand with a 120 – to – 150 – grit abrasive screen or No. 2 steel wool.

Final Thoughts

What happens if you put the second coat of polyurethane without sanding? There is no difference at all when you do so. But the surface would be better if you use the foam brush to avoid brushstrokes during the process. Keep in mind some other polyurethane formula applications to get the best final results.