Can You Put Polyurethane Over Shellac?
Don’t know whether polyurethane will work on your wooden surfaces? Read on to find it out!
Even if you are not an owner of wooden floors or furniture, you definitely know how hard it is to maintain them to keep wood in the same gorgeous condition! This is why many homeowners who have wooden items want to know how they can make their possessions serve longer, remaining in a good condition.
For this purpose, folks often consider using different coatings and finishes to protect the wood, and polyurethane is one of them.
But here is the question: can you put polyurethane over shellac?
In this article, we will give you the answer.
You will learn more about applying polyurethane over shellac. In particular, we will tell you in detail what comes with applying polyurethane over different kinds of shellac finish.
Also, you will find out what polyurethane and shellac are exactly. We will explain how to apply polyurethane over shellac, guiding you step by step through the process.
In addition, you will find out whether there are any problems that you might face when using this method. Finally, you will learn about the most suitable brands of polyurethane finish suitable for this kind of application.
Can Polyurethane Be Applied Over Shellac Finish?
If you are an owner of wooden floors or wooden furniture, you know very well how hard it is to maintain such objects and surfaces to make them look gorgeous! Wood is a wonderful material that looks classy and rich, but to remain the same good, it requires quite an effort to keep it like that, especially if wooden objects or surfaces are actively used in your home.
This is why many homeowners consider coating polyurethane over shellac to preserve their wooden surfaces and objects and make them last longer.
But the common question they face is whether polyurethane can be used over shellac floor coating, for example.
The answer is both yes and no. How come?
See, it depends on the type of shellac finish you use. Below, we explain what exactly that means.
Applying Polyurethane Over Waxed Shellac
The rule of thumb says that it is recommended that you don’t apply polyurethane over waxed shellac. The reason is that polyurethane usually doesn’t stick to waxed shellac well enough. And since regular shellac is most likely to be waxed shellac, you will definitely end up with problems later.
In addition, there are a couple of more problems you might face should you choose this kind of application:
- You will have to melt the topcoat over the wax to put something over the waxed shellac
- Polyurethane will not be able to mix or blend with something
As a result, you will get polyurethane that can’t stick to the waxed shellac properly, and eventually, this mixture will fail. In the end, you will not get the beautiful, lavish wood you were craving.
Applying Polyurethane Over De-Waxed Shellac
So what about applying poly over de-waxed shellac instead? Will that work? Well, yes, it will! It doesn’t matter whether the polyurethane you use is oil-based or water-based poly, it will adhere to dewaxed shellac quite well.
By the way, here is an interesting fact for you: did you know that dewaxed shellac is also used for applying the coating between stain and polyurethane?
That is because it creates a strong bond coat. This is why, if you want a long-lasting wooden surface that looks like it’s polished and glossy, you can apply polyurethane over dewaxed shellac without hesitation.
So, as you can see now, it is possible to put polyurethane over shellac. You just need to be careful and watch what kind of shellac coating you are dealing with!
Depending on this nuance, the application process may end up either successfully, leaving you with a glossy and polished-looking wooden surface, or fail, turning into a disastrous experience.
Ways Of Putting Polyurethane Coating Over Shellac
It is a well-known fact that shellac can bring a perfect finish to your wooden furniture or floors. However, there is a downside of shellac that can ruin it all: you might want to use a polyurethane finish to increase the durability of your wooden surface or object.
The only problem is that it is not recommended to apply polyurethane over the regular waxed shellac. However, everything is not so bad and you can still apply poly over de-waxed shellac successfully!
But in order to be able to do that, you must be aware of what steps you should take first of all. Below, we suggest you a few steps on how you can apply poly over shellac.
Dilute Shellac With Alcohol
To begin with, you will have to mix the shellac you use with alcohol to be able to put it onto the wood. Then, you may calculate the required volume of shellac and alcohol based on the dimension of your wood.
Apply The Mixture Onto Your Wooden Surface
After you figure out the required volume of shellac and alcohol and prepare the mixture, you can apply it to the wood, using a bristle brush. Simply dip the brush into the solution you have made and brush back and forth on your wooden surface.
Sand The Surface
Sanding is required and we would not recommend you skip this step! See, you should sand your wooden surface to wipe away any dust, dirt, or oil from the wood. For that purpose, you can use sandpaper to do the job.
After you sand the surface, it is time to apply a coat of polyurethane. For that purpose, you can use either a clean brush or cloth (make sure it is also clean!). If you use water-based poly, it will not take you much time to cure. But if you are using oil-based polyurethane, be ready that it will take plenty of time to fully dry! In this case, make sure you wait before the first coat cures.
Only after the first coat dries completely, you can proceed with sanding once again. Then, when all the dust is wiped away, you can apply a second coat of polyurethane. In total, 3-4 layers of a coat of polyurethane should be applied to get the best results.
So, as you can see now, applying polyurethane is quite tedious work. However, if you do everything right according to the given recommendations, you can be sure that you won’t have to redo the whole thing because something went wrong!
Applying Polyurethane Over Shellac. What Problems Can I Face?
Since you can’t apply poly over any kind of shellac, homeowners are often concerned about potential problems they might face during the application procedure. But is there really anything you should be afraid of?
In fact, you should have no trouble with using shellac over polyurethane, just make sure it is dewaxed shellac you are using! In this case, you can apply it without hesitation even though this wonderful finish covers everything. It will stick to the polyurethane just fine!
The only possible drawback is, poly is a soft and flexible material, while shellac is the opposite, being hard and inflexible. As you could already guess, if polyurethane moves even a bit, the topcoat (which is shellac) will stay still and won’t move, leading to cracking over time.
Which Polyurethane Finish Is The Most Suitable For Shellac?
Even though you are now aware of the basic nuances you may face while using a poly over shellac, you can still mess up with the task if you use the wrong product! Most homeowners would just decide to go out and buy some for their furniture. But there are so many brands out there on the market! How do you know which one to choose?
First of all, hold on! There are tons of brands out there, that’s true, and choosing the proper one can be challenging, especially if you are not a pro.
However, buying the very first one you see would be a mistake since it will surely leave a lousy look on your furniture. As a result, you will be wasting both time and money.
So, we recommend you take a closer look at a few of the best brands of polyurethane to choose from. Like that, you will be able to understand better what you should search for first of all.
- Interlux Brightside Poly Paint. This product comes with a diverse set of colors and it gives a gorgeous sheen and sparkling look on your wood!
- Rust-Oleum Varathane Interior Satin Finish is a good idea if you want a durable finish on your wood. This product dries up quickly and is easy to work with. Additionally, it can be easily cleaned with just some soap and water
- Minwax Fast-Drying Clear Gloss extracts raw beauty from your wood. In addition, it protects wood from marks and stains
Well, now you are better informed about the nuances of polyurethane over shellac application! You know that it is possible to use poly over shellac and you are also aware of the kind of shellac you should stick to in this case.
In addition, we explained in detail how the application procedure should go to be successful. Finally, now you know what polyurethane brands are considered to be the best ones out there to be used over shellac.
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Frequently Asked Questions
⭐What happens when you shellac over polyurethane?
The shellac will stick to polyurethane of course, but since it’s not flexible (unlike poly), it can crack later.
⭐Can you put polyurethane over zinsser shellac?
Polyurethane should be applied only over the dewaxed shellac.
⭐What grit sandpaper should I use to sand before polyurethane?
Use 120-grit sandpaper on refinished pieces and 80-grit on new wood. Then, sand with 180-grit until you remove all the marks left by the 120-grit.
Written by Melinda Sherween