Can You Put Polyurethane Over Shellac? (Answered!)

In the instructions provided by several different shellac manufacturers, I read that polyurethane should never be applied over shellac.

A few reputable wood finishers can say the same.

As a result of receiving several inquiries from you all, I chose to conduct my research to provide an answer to the subject of whether or not polyurethane may be applied over the top of shellac.

Stay here, and I’ll answer your inquiry when I get a chance.

But before we get into that, let’s get the most important thing out: if you’re new to woodworking, you need to know the difference between shellac and polyurethane.

Okay, done; let’s get started;

VIDEO: Shellac Under Polyurethane

Can Polyurethane Be Applied Directly Over Shellac?

Since shellac completely seals the surface, polyurethane shouldn’t be applied on top of it. 

However, there are situations in which woodwork coated with shellac buffs out white markings when a spatter of water gets on it. 

The solution to this problem is to scrape off the shellac and refinish the woodwork using poly.

If you have to put poly over shellac, follow the instructions below; however, before you do that, here are the tools you will need. 

• Dewaxed shellac/ waxed shellac
• Pure and quick-drying polyurethane from Minwax.
• Alcohol with the flavoring removed. 
• Brush 
• Wet tack Cloth
• Sandpaper.

Step 1: Dilute the shellac.

Shellac can be made thinner by mixing 1 part denatured alcohol with 3/4 of a pound of cut shellac. Mix the ingredients thoroughly.

Step 2: Sand the wood 

Sand the wood’s surface with the sandpaper you choose to use.

Step 3: Put on the first layer of paint.

 Using the brush, apply a skinny coat of the diluted shellac, and then abandon the board for forty-five minutes to allow the shellac to absorb the wood and cure thoroughly.

Be sure to apply several thin coats of shellac to strengthen the polish and reduce the likelihood of cracking.

Step 4: Sand the surface of the wood

Sand the wood only lightly, and then use a paper towel that has been wet to remove the dust.

Step 5: Apply the poly.

The next step is to apply the polyurethane over the shellac with a separate brush and allow it to dry for around three to four hours.

 Step 6: Sand the wood one more time

 After the last layer of polyurethane has had enough time to dry, sand the wood again.

 Step 7: Apply the last coat to the surface.

 After the sanding is complete, wipe away the dust with a paper towel that has been discarded, apply the final coat of polyurethane, and allow it to dry for three to four days.

A coat of shellac over the polyurethane?

 Shellac is a durable sealer that can be used independently without needing a topping finish of polyurethane. So if you have been concerned about applying polyurethane over shellac, you no longer need to be.

Shellac has been dewaxed and is suitable for water-based finishes such as polyurethane. 

To add, it is frequently employed as an “adapter” layer and can be applied on top of or underneath a polymer that is either water- or oil-based.

Even though shellac is compatible with most finishes, it is not compatible with lacquer or catalyzed finishes.

The aforementioned is valid only when utilizing the “dewaxed” shellac. This is because shellac that contains wax is incompatible with other under/over finishes.

Is It Possible to Apply Polyurethane on Top of Zinsser Shellac?

 It is not recommended to apply poly over shellac, according to the manufacturers of Zinsser shellac. 

Despite this, they believe applying polyurethane over the Zinsser sanding sealer product is acceptable, which raises several problems.

You might be wondering at this point what the best way forward is to proceed.

After conducting several tests, I applied Minwax poly over Zinsser amber shellac, and the results gave me the impression that everything was functioning normally.

Is There a Top Coat That Can Be Applied Over Shellac?

Shellac can have a top coat applied over it, which is conceivable.

However, it would help if you got ready to deal with many obstacles to remove them.

You will need to remove the nail polish with a remover for nail polish that does not contain acetone. Should you fail to do so, you will inevitably destroy both of the applications.

In addition, you can put conventional nail paint over the de waxed shellac without any problems. However, it would help if you never used shellac over conventional nail polish since it will prevent the polish from curing properly.

Similarly, can a coat of shellac finish be put on top of the topcoat?

Yes, you can.

Sometimes I apply three coats of it to be more durable and have more color. The difficulty is that you will need to devote significantly more time to the process for the acetone to obliterate it.

Also, if you are interested in extending the life of the Shellac coating that you have on your nails, consider the following suggestions:

• Never try to hasten the drying process.
• Maintain a moist environment for it.
• When drying, try to stay out of direct sunlight.
• You should finish it up with a top sealer coat.

Can shellac be painted over with regular paint?

Shellac can be painted; however, unlike painted cabinets, its glossy surface does not retain paint well.

There will be further preparation that has to be done to it before you paint it. For example, before you start painting, you must strip off the shellac first. 

Because of this, you can prevent the paint from peeling off the surface in the future.

How Long Does The Shellac Have To Dry Before The Polyurethane Can Be Applied On Top Of It?

Shellac requires less time to cure appropriately than polyurethane, an oil based polyurethane or a water based polyurethane, which can take up to 24 hours. It should be let to sit for an hour before sanding or screening as long as the product is not over-applied.

The second coat should take two to three hours to dry.

Compared to polyurethane, this finish has lower durability and lower resistance to scratching.

The Finish That Looks Best Over Shellac Is:

The original satin finish of the Waterlox TB.

The Satin Formula of the Waterlox Original Wood Finishes is by far the most sought after of all of the available options. 

This finish, which is both beautiful and protective, is an enduring classic that can be applied to any natural stained wood surface. 

It can be administered with a spray bottle, a lambswool applicator brush, a cloth roller, or a brush. It is also quite simple to use. 

It is not hazardous to food and is simple to fix.

With a satin sheen appearance (20°-25° gloss level), it forms a protective yet elastic finish against common household spills, moisture, and foot traffic; it penetrates and waterproofs when used as a finishing system in conjunction with Waterlox Original Sealer/Finish; and it has a gloss level of between 20° and 25°.

This time-honored durable finish is simple to apply and shields bare wood from the damaging effects of rain, sunshine, and bleeding. 

A wide range of wood floor surfaces, including kitchen cabinets, furniture, entertainment centers, architectural millwork, and a number of other types of wood surface, benefit from the satin finish.

When you use any other product for finishing, you cannot generally expect to achieve the same level of protection, shine, and superb color as you would with this one.

 Simply put, the reason why it was feasible to make it operate like magic was due to the fact that it contained both natural and synthetic oils in equal parts.

This shellac finish is considered environmentally beneficial and protective due to the fact that 90 percent of the resin component comes from renewable resources. 

When used as a finishing method in conjunction with Waterlox Original Sealer/Finish, it penetrates as well as waterproofs the surface being treated.

This transparent finish is highly valued by professionals and is sold all over the world. It is also non-toxic.

Because pure Tung oil is used in the finishing process, there are no solvents or volatile organic compounds (VOCs), also known as chemically-singed brain-cell-killing VOCs, present in the coating that you or your family will be breathing in.

FAQ on Can You Put Polyurethane Over Shellac