How to Remove Polyurethane

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Has your polyurethane finish outlived its beauty and protective ability? With a few tips, you can remove polyurethane yourself, in a few simple steps. Don’t worry, you don’t need to be an expert on woodworking. Here’s a simple guide on how to remove polyurethane from your wood furniture or floor.

How to Remove Polyurethane

The beauty and protection that polyurethane gives to our wood fade with time. If you use oil-based products, you will begin to notice your floor or furniture turn yellow after a few years. If you use water-based polyurethane, your floor will remain clear yet it will begin to lose its resistance to alcohol and acids after some time.

Such depreciation makes it necessary to remove your polyurethane finish from the wood. We’ll discuss two main methods to remove polyurethane, one using chemical removers and another without any sanding involved.

Wood with polyurethane

How to Remove Polyurethane Using Paint Stripper

First, you should take some necessary precautions before removing polyurethane from your piece of wood. Some of them are essential safety measures in a bid to protect yourself. Use this guide as an important reminder to stay safe while using a paint stripper.

Create Proper Ventilation

Since you’re using chemical removers, you’ll need to have a cross-ventilation system to strip paint as well as finish and to protect yourself and anyone around you. This is not necessary if you are working outside. If you are working indoors, you will need to open all the room doors and windows. 

You can also set up two fans, blow air inwards, and the other one blows air out from the room.

Protect Other Items

Depending on what you are working on, you should try and limit any collateral damages. For example, you have to protect the floor and any other surface from chemical drips. 

It is good to clear the entire room of all the furniture and only return them when you are through with the process. You can use tape and old newspapers to cover other parts and items that the chemicals could damage.

Wear Safety Gadgets

The chemicals that you will use as a paint stripper can cause severe health issues and injuries. So, you need protective equipment like gloves and safety goggles. We also recommend that you put on closed shoes, a long-sleeved shirt, and long pants if possible.

Additionally, wear a respirator to protect yourself from hazardous fumes that might affect your lungs. 

Pick the Right Paint Stripper

Before you begin the work, you have to make sure you choose the right paint stripper for this job. Chemical strippers with methylene are the most effective removers in the market. 

However, you must know that the chemical in such removers makes them harsh and reactive. They pose a danger to the human skin and respiratory system.

If you are not comfortable with them, you can opt for the mild water-based strippers instead. This can be a better option when you’re removing polyurethane but still trying to preserve a wood stain. However, they are not as effective as chemical strippers and you might need to put in more effort and time.

1. Apply the Stripper

Now that we’ve taken all the necessary precautions and preparations, it’s time to apply the stripper.

Person applying polyurethane

What you Need

The following are the most crucial items you will need:

  • Old paintbrush
  • Plastic Tarp

Step One: Coat the Polyurethane

Use an old paintbrush to paint a liberal coating of paint remover to cover the polyurethane coat.

It will help if you put in a lot of paint strippers. This is so because the surface needs to look wet and ensure that you cover any nooks and crannies.

The type of brush you want to use in this stage is essential. Just make sure you use a brush that you won’t have to use for anything else later.

Step Two: Give it Time to Soak

Allow the paint stripper some time to soak into the surface and do the work for you. If you are using a chemical-based paint stripper, ten minutes will be enough. However, a water-based stripper will take much longer. They take about six to twenty-four hours at most.

The surface will be ready when the polyurethane begins to wrinkle and bubble. It is good to check manufacturer information on the product. It will help you know how long your paint stripper will take, to avoid any guesswork.

Step Three: Cover the Project During Breaks

Sometimes you might need to take a break or continue with the project the following day. If such situations arise, ensure that you cover your project. You can use a plastic tarp to keep the paint stripper wet.

You can place it nicely over to cover the surface of your wood furniture or floor. Try to limit any activity from people or pets in your working space.

2. Scrub and Clean

The second stage of this process entails a lot of manual work, once you’ve applied the chemical stripper, it’s time to scrub the floor and clean it.

What You Need

  • Metal or Plastic scraper
  • After wash
  • 159-grit sandpaper or ball of steel wool

Step One: Scrub the Polyurethane Down

Use a metal scraper to peel off the wrinkled and bubbled layer gently. If you fear putting scratches on your wood, you can use a plastic scraper instead.

Ensure that you scrub in the wood grain direction to avoid damaging the surface.

Young boy preparing to remove polyurethane on the chair

Step Two: Scrub Corners and Small Areas

The scraper will not be so useful in decorated areas and hidden corners. Instead, you can use a stiff nylon brush. Its bristles let you maneuver to get hidden or hard to reach polyurethane pools. Be gentle with the bristles so as not to scratch your wood.

Step Three: Apply an After Wash

After scrubbing, use an after wash (solvent) to wash down the polyurethane. You can also use it to clean the surface off any remaining paint stripper. You can use a paper towel or soft cloth to rub across the surface until you there is no debris remaining. 

Step Four: Assess Your Work and Repeat if Necessary

If you are not satisfied with the work you have done above, go through the same process again. Begin by applying the paint stripper to washing the surface clean.

Step Five: Sand the Surface

Sanding is part of making sure that you get 100% satisfaction. The above process will only remove most polyurethane. So sanding the surface down removes whatever remains.

You can either use a ball of fine steel wool or 159-grit sandpaper. They are the best when it comes to smoothing out and cleaning the last of the polyurethane.

Step Six: Clean Your Working Area, Equipment, and Tools

The chemicals in chemical-based paint strippers are inflammable. So it would be good if you soaked the discarded rags/towels in the water. Please do the same with any other tool.

You can take whatever is remaining to your town’s hazardous waste disposal unit. Never throw the rags or the chemicals directly into the trash can or sewer.

How to Remove Polyurethane Without Sanding

Granted, it is also possible to remove polyurethane without sanding. Depending on your surface, you will have to pick a suitable look. In this case, a stripper paste is the best option. 

Stripper pastes lack any phenol in its composition. However, it has the ideal alkalinity level: only 3 %. Plastics and rubber are unstable in this paste, so avoid any contact whenever you are using it. 

Person handling wood pieces

A stripper paste penetrates the polyurethane coatings and destroys the layers without any toxicity. Then washing washes everything off. You can remove polyurethane without sanding in three easy steps: 

  1. Apply the Paste: Use a brush or spray to apply two thin layers of the stripper paste on the surface.
  2. Give it Time: Leave the substance for a while and then wash off. In most instances, you will clear the polyurethane with the first application.
  3. Reapply if Necessarily: Repeat the above steps if you do not get the desired results. Reapplication is mainly necessary when using old wood. 

Can You Remove Polyurethane with Light Sanding? 

You can remove polyurethane from your piece of furniture or floor by only sanding. However, it takes a lot of labor, so it is not suitable for large surfaces.

The method is effective as long as you sand the shiny upper coat with fine-grade sandpaper. Ensure that you wipe it down after completing everything. You can repeat the process as many times as you want to until you get your desired results.

Step One: Start with the Flat Surface

Begin your sanding from one end of the flat surface on whatever you are working on. Then use an orbital sander to scrub off the polyurethane. Make sure you sand along the wood grain to avoid scratching and destroying the surface.

Step Two: Move to the Curved Areas

When done with the flat surface, then you can move to the curved, irregular decorations and rub the layers. This area needs a lot of attention so you should take your time.

Bottom Line

The whole process of removing polyurethane is not as complicated as many people put it. You can choose any of the above processes and apply the right techniques to make it happen. It is crucial that you also take precautions to avoid accidents and related injuries.

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.