How to Remove Polyurethane From Wood? (3 Methods)

Polyurethane adheres perfectly to the wood, so it’s hard to remove it. So, how to remove polyurethane from wood?

To remove polyurethane from wood, use a paint stripper, vinegar, or sand it off. To sand off the polyurethane, use fine-grit sandpaper (150-grit). The sandpaper will remove the polyurethane coating and leave a smooth wooden surface behind.

A paint stripper will remove multiple coats of polyurethane. The paint stripper will penetrate and dissolve the paint particles of polyurethane, making it easier to wipe sealant off in 15 minutes.

Removing Polyurethane Without Sanding

Can You Remove Polyurethane Without Sanding?

You can remove polyurethane from wood without sanding. To do this, use a paint stripper or baking soda. The paint stripper will dissolve the polyurethane coating and liquefy it, making it easier to wipe it off. You can also use a paint thinner instead of a paint stripper. 

However, sanding the polyurethane is the best way to remove it. That’s because sanding doesn’t damage the wood and leaves behind a smooth surface for the next paint (or sealant) to stick to. 

Besides removing polyurethane, sanding will also remove the imperfections on the wooden surface, while the paint stripper won’t. Sanding will even out the wood surface and remove bumps from it.

On the other hand, a paint stripper can damage the wood if left for too long. Also, after removing polyurethane with a paint stripper, you must clean the paint stripper residue, or the next coating won’t stick. 

Removing Polyurethane Without Removing Stain

Can You Remove Polyurethane Without Removing The Stain Underneath It?

You can remove polyurethane without removing the wood stain underneath by using a mild paint remover. A water-based mild paint remover is not strong enough to affect (remove) the wood stain, but it will remove the polyurethane. However, leaving the mild paint remover for too long will also remove the wood stain.

Also, you can use a mixture of denatured alcohol and lacquer thinner to remove polyurethane without affecting the wood stain. But, you must wipe off the mixture within 15 seconds to prevent it from penetrating the wood stain. 

Removing polyurethane without removing the wood stain underneath doesn’t always work. You will often notice etched spots on the stain, especially if you leave the paint remover for too long. You must apply a fresh coat of wood stain to hide (cover) these etched spots.

How To Remove Polyurethane From Wood?

Removing polyurethane from wood isn’t hard, but you must use the right methods. If you use the wrong method or tools, you can damage or stain the wood surface. Here are 3 methods that you can use:

Method 1: By Sanding

By Sanding

The best way to remove polyurethane from wood is by sanding it off. The abrasive side of the sandpaper will remove the glossy layer of polyurethane and smooth out the wooden surface. 

Here are the tools you need for this method: 

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

To remove polyurethane from a wooden floor, you must use a floor or orbital sander.

Here is a guide for this method:

  1. Clean the wooden surface to remove debris that can damage the sandpaper. 
  2. Attach the sandpaper to the bottom of the sander. 
  3. Sand the polyurethane off.
  4. Remove the sanded dust.
  5. Clean the wood. 

You must frequently check the wooden surface while sanding 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

You can use paint strippers to remove polyurethane from wood. The paint stripper will soak into the polyurethane and dissolve it, making polyurethane lose its bond to the woo. 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
  • Plastic putty knife
  • Clean rags
  • Wire sponge

Here is a guide for this method:

  1. Clean the wooden surface using clean rags.
  2. Apply a layer of paint stripper over the polyurethane. 
  3. Wait for 20 minutes.
  4. Inspect the polyurethane coating; if the polyurethane has developed bubbles, remove it. 
  5. Removing polyurethane by scraping and wiping the polyurethane and the paint stripper off the wood. 
  6. Re-apply the paint stripper over leftover polyurethane.
  7. Clean the wood with warm water to remove paint stripper residue. 

Tip: You must 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 good polyurethane stripper.

To use this method, you’ll need:

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

Here is a guide to using vinegar to remove polyurethane:

  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.
  5. Wait until the polyurethane starts to bubble. 
  6. Use a scraper to remove the polyurethane.
  7. Wipe off excess baking soda or polyurethane from the wood

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

Other Methods/Products Use Can Use:

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

Acetone

Acetone is a great fresh polyurethane remover. However, acetone can’t remove cured polyurethane because the liquid isn’t strong enough to dissolve it.

If the polyurethane is over 3 days old won the wood, acetone won’t remove it. 

Lacquer Thinner

You can use lacquer thinner to dissolve and remove polyurethane from wood. Lacquer thinner can remove topcoats such as polyurethane, varnish, and lacquer. However, don’t let the lacquer stay over the wood for too long as it can discolor the wood. 

You can use lacquer thinner to clean polyurethane brushes too. 

Alcohol

Alcohol can remove fresh polyurethane, but it won’t remove cured polyurethane. To remove polyurethane with alcohol, use must use denatured alcohol. That’s because denatured alcohol is the most potent at removing polyurethane.

However, if the polyurethane has cured, you must mix denatured alcohol with another solvent (such as lacquer thinner) to remove it. That’s because denatured alcohol can’t remove cured polyurethane on its own. 

Citristrip

You can use Citristrip to remove polyurethane from wooden surfaces. Citristrip is an industrial-strength remover that removes multiple layers of paint and sealant. This paint remover will remove fresh and cured polyurethane within minutes. 

Methods/Products You Should Avoid:

TSP (Trisodium Phosphate)

TSP (Trisodium Phosphate) is an alkaline-based cleaning agent that is not strong enough to remove polyurethane. This cleaning agent is used to clean, degrease, and remove dirt from different surfaces, but it 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 soften polyurethane, but it can’t remove it. So, you can use turpentine to soften polyurethane and then use a paint remover to remove the polyurethane. However, turpentine on its own won’t remove polyurethane, especially cured polyurethane.

Mineral Spirit

Mineral spirit isn’t strong enough to dissolve and remove polyurethane. So, you shouldn’t use mineral spirits for polyurethane.

Mineral spirit is a petroleum-distilled solvent that removes latex and oil-based paints. But, can’t remove top coats like polyurethane and varnish.

Goo Gone

Goo gone can’t remove polyurethane. You can use goo gone to remove stains and dirt from surfaces. However, goo gone isn’t strong enough to penetrate or dissolve polyurethane. 

Final Words

You can remove polyurethane from wood using a paint stripper, paint thinner, baking soda and vinegar, or sanding it off.

To remove polyurethane without affecting the stain (or paint) underneath, use a mixture of lacquer thinner and denatured alcohol over the polyurethane for 15 seconds and wipe it off. 

Always read and follow the manufacturer’s instructions before using a paint stripper or remover. 

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