How to Remove Polyurethane From Wood? (3 Methods)

The strong adhesion of polyurethane makes it difficult to remove the top coat from wood. So how do you remove polyurethane from wood without worrying about wood damage?

The best way to remove polyurethane from wood is to sand the polyurethane coating off using fine (150-grit) sandpaper. The sandpaper will remove the polyurethane coating and still give you a smooth wooden surface.

You can also remove multiple coats of polyurethane from wood using paint strippers. The paint stripper will penetrate and dissolve the polyurethane making it easier to wipe or strip the paint off in about 15 minutes.

This post reveals all you need to know about removing polyurethane from wood including different products that work effectively. So, let’s dive in.

Can You Remove Polyurethane Without Sanding?

Can You Remove Polyurethane Without Sanding?

You can remove polyurethane from wood without sanding. To do this, you’ll need to use a paint stripper to remove the polyurethane. Paint strippers help to dissolve the polyurethane in minutes making it easier to wipe or scrape off the polyurethane from your wood. You can also remove polyurethane using paint thinner.

Though sanding off polyurethane is often regarded as the best way to remove the paint from wood, it’s not the only method that works. There are other ways to remove polyurethane from wood without sanding and the best method is to strip the polyurethane off of the wood. This method involves using a soy-based or chemical-based paint stripper to remove the polyurethane layers from the wood.

Paint strippers are chemical compounds that are dissolved in a solvent. These compounds penetrate and dissolve the polyurethane layers from the inside. When the polyurethane is dissolved, it swells up losing its bond with the wood. When you notice the polyurethane swelling, it can either be stripped off or wiped off of the wood.

You can also use paint thinner to remove polyurethane. Paint thinners are solvents that work similarly to paint strippers. The solvents break down the polyurethane causing the paint to lose its bond with the wood and bubble up.

Can You Remove Polyurethane Without Removing The Stain Underneath It?

Can You Remove Polyurethane Without Removing The Stain Underneath It?

It’s possible to remove the polyurethane topcoat without removing the wood stain underneath. To do this, you’ll need a mild paint remover.

Many professional painters advise using a mixture of denatured alcohol and lacquer thinner to remove the polyurethane. However, you’ll need to wipe off the lacquer thinner mixture quickly before it penetrates the wood and removes the stain. The advised time to wait before wiping the mixture is 15 seconds.

Oftentimes, polyurethane is applied to wood to protect an existing stain on the wood but to remove the polyurethane without removing the stain underneath is usually a problem. This is because whatever method you use to remove the polyurethane will affect the stain underneath too. Well, not all methods.

You can remove polyurethane using a mild paint remover, especially those that are water-based. This remover is not as strong as chemical-based remover so the chances of it affecting the stain underneath are reduced.

You can also use a mixture of lacquer thinner and denatured alcohol to remove the polyurethane without affecting the stain. The mixture is very potent and will remove the polyurethane but you need to wipe it off quickly (in 15 seconds) before it penetrates the wood and removes the stain.

You should also know that removing polyurethane without removing the stain underneath doesn’t always work 100%. In some cases, you may notice etched spots on the stain especially if you leave the paint remover on the polyurethane for too long. These spots are usually small and can be touched up by spraying a fresh coat of the stain on the wood.

How To Remove Polyurethane From Wood (3 Methods That Work)

Removing polyurethane from wood without damaging the wood is often difficult but not anymore. This guide will reveal 3 methods to remove polyurethane from wood easily, quickly, and without any wood damage.

Method #1: By Sanding

By Sanding

The first and most common method to remove polyurethane from wood is to sand the polyurethane off of the wood using sandpaper.

For this method, the abrasive side of the sandpaper is used to remove the polyurethane coating. The great part about this method is that it removes the polyurethane and leaves you with a smooth wooden surface that can be finished without any additional prep.

To use this method, all you need are:

  • Sandpaper
  • A pair of gloves
  • Breathing protection
  • A sander (if necessary)

If it’s a wooden floor that you want to remove polyurethane from, you’ll need to use a floor or orbital sander that is capable of covering large surfaces quicker.

Here is a guide for this method:

  1. Wipe and clean the wooden surface to remove debris that can damage the sandpaper
  2. Attach sandpaper to the bottom part of the sander
  3. Sand the polyurethane off
  4. Remove the sanded dust.

Tip: You should frequently check the wooden surface as you sand to know if the polyurethane has been removed. If you continue sanding after the polyurethane has been removed, you’ll gouge the wood.

Method #2: Using Paint Strippers

Using Paint Strippers

Paint strippers also work to remove polyurethane from wood. Paint strippers are chemical compounds that often contain methylene chloride (a key ingredient that removes polyurethane).

There are two types of paint stripers; chemical-based and soy or water-based paint stripper. Chemical-based paint striper is more effective but it also contains toxins so you should only use it outdoors or in well-ventilated rooms. Also, put on a face mask and a pair of gloves while handling the paint stripper. Soy-based paint stripper is less toxic.

For this method, the paint stripper will soak into and dissolve the polyurethane layers making the poly lose its bond to the wood. This will cause the polyurethane to bubble up and peel off the wood.

To use this method, you’ll need:

  • A paint stripper
  • Paint scraper
  • A pair of gloves
  • Breathing protection
  • Plastic putty knife
  • Clean rags
  • Wire sponge

Here is a guide for this method:

  1. Wipe and clean the wooden surface with clean rags
  2. Apply a layer of the paint stripper to the polyurethane
  3. Leave the paint stripper for about 20 minutes
  4. Inspect the wood. If the polyurethane has developed bubbles, then it’s time to remove it
  5. Remove the polyurethane by scraping and wiping the polyurethane and paint stripper off of the wood
  6. Wipe and clean the wood to get rid of paint stripper residue.

Tip: You should always follow the manufacturer’s instructions when using a paint stripper.

Method #3: Using Baking Soda and Vinegar

Using Baking Soda and Vinegar

You can also remove polyurethane from wood by using a mixture of baking soda and vinegar. Baking soda is an alkaline substance and vinegar is considered to be acidic. Mixing both will create a fizz of carbon dioxide that will remove the polyurethane.

To use this method, you’ll need:

  • Baking soda
  • Vinegar
  • A clean bowl
  • Turning stick

Here is a guide for this method:

  1. Mix equal parts of baking soda and vinegar in a clean bowl
  2. Add a cup of warm water
  3. Stir the mixture using a turning stick
  4. Apply the mixture to the polyurethane and leave for a few minutes till the polyurethane starts to bubble
  5. Use a scraper to remove the polyurethane from the wood
  6. Wipe off excess baking soda or polyurethane from the wood

Tip: While scraping, ensure to do so along the wood grain.

Different Products You Can Use To Remove Polyurethane From Wood

Next, let’s check out other methods and products that work to remove polyurethane from wood.

Acetone

Acetone is a natural paint remover that can be used to remove fresh polyurethane paint. Acetone can’t remove cured polyurethane because the liquid isn’t strong enough to dissolve polyurethane after it has cured on wood. If the polyurethane is over 3 days old on the wood, acetone will do very little to remove it.

Lacquer Thinner

Lacquer thinner is strong enough to dissolve and remove polyurethane from wood. Lacquer thinner is designed specially to remove top coats like varnish, polyurethane, and lacquer.

You can even use lacquer thinner to clean and remove polyurethane residue from your painting equipment after applying polyurethane on wood.

However, don’t let the lacquer thinner stay too long on the wood or it will cause wood damage and discoloration.

Alcohol

Alcohol can remove polyurethane from wood but it will struggle with cured polyurethane. You should also know that denatured alcohol (alcohol with additives) is the most potent at removing polyurethane from wood.

If polyurethane has cured, you’ll need to mix alcohol with another solvent (such as lacquer thinner) to remove it because the alcohol isn’t strong enough on its own against cured polyurethane.

Citristrip

Citristrip can remove polyurethane from wood. Citristrip is an industrial-strength remover used to remove anything from multiple layers of paints, sealants, and so on. The stripper can be used to remove fresh and cured polyurethane in minutes.

Citristrip doesn’t contain any harmful substance and the remover can be used indoors due to the fresh citrus scent that it produces. Unlike harmful chemicals and strippers, you don’t have to worry about toxins with citristrip.

Different Products You Shouldn’t Use To Remove Polyurethane From Wood

TSP (Trisodium Phosphate)

TSP (Trisodium Phosphate) is an alkaline-based cleaning agent that is not strong enough to remove polyurethane.

TSP is designed to be used to clean, degrease, and remove scum from different surfaces. The product can’t remove polyurethane. The best TSP will do at removing polyurethane is to gunk up the polyurethane or make it sticky.

Turpentine

Turpentine can’t remove polyurethane from wood but it can be used to soften the polyurethane before using another method. On its own, turpentine will struggle against polyurethane, especially cured polyurethane. But you can use it as a preparatory solvent to soften the polyurethane and make it easier to remove using a paint stripper or lacquer thinner.

Mineral Spirits

You can’t remove polyurethane from wood using mineral spirits because mineral spirit is not strong enough to penetrate a polyurethane layer.

Mineral spirit is a petroleum-distilled solvent that will remove latex and some oil-based paints but it can’t remove top coats like polyurethane and varnish.

Go Off

Go off can’t remove polyurethane. Go off is a type of remover wipe designed to remove makeup products, face paints, and the like. It’s not powerful enough to remove any paint especially not a top coat like polyurethane.

Final Words

In summary, you can remove polyurethane from wood using different methods such as paint strippers, paint removers, solvents, and sanding.

You should consider the condition of your wood and the ventilation in the room before you pick a removal method. Remember to protect yourself with breathing protection and a pair of gloves when using chemical-based products and solvents.

Finally, to remove polyurethane without affecting the stain underneath, you should use a mixture of lacquer thinner and denatured alcohol but ensure to wipe off the mixture quickly (in 15 seconds) before it affects the wood stain.

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