Last Updated on April 5, 2023 by Ernest Godia
Sanding is a primary way to remove polyurethane from previously finished wood or hardwood floors. But what do you do when this method is not on the table?
While polyurethane is one of the most durable wood finishes on the market, the sealant does not last forever. You must refinish the wood surface occasionally to maintain its protection.
To do that, you must know how to remove polyurethane from wood without sanding.
This article shares three safe and effective methods of removing a coat of polyurethane from wood without damaging the surface. Following the tips and guidelines in this write-up is essential to ensure the best results.
How to remove polyurethane from wood without sanding
You can remove polyurethane from wood without sanding by using a citrus paint stripper or a mix of lacquer thinner and denatured alcohol. Alternatively, you can use a solution of baking soda and vinegar to remove polyurethane from wood without sanding it.
These products react with polyurethane and weaken its bonds. This allows you to remove the dissolved coat of poly from the wood by scraping it off with a putty knife. After that, you can wipe the surface with a wire brush and clean it with water or sand the wood to smoothen it.
Method 1. Using a paint stripper
The most effective way to remove dry polyurethane from wood without sanding is using a chemical stripper. The substance is highly effective against various finishes, including polyurethane.
It works by emulsifying the coat of wood finish, weakening its bonds, and allowing it to lift off the wood surface easily.
Once you apply the stripper to the dry sealant, it gets to work immediately, causing the polyurethane finish to bubble up in minutes. However, we recommend using a water-based stripper that is less caustic and takes longer to work.
Tools and materials to use in this method
- Citrus paint stripper
- Plastic scraper or putty knife
- Eye protection (a pair of goggles)
- Chemical-resistant hand gloves
- Wire sponge
- Clean rags
- Paintbrush
- Respirator mask
How to remove polyurethane from wood using a paint stripper
Once you have everything assembled and within reach, follow these steps to remove the old coat of polyurethane from your wood for refinishing.
#1. Prepare the space
Start by removing any objects that might stand in your way to reduce the risk of accidents. After that, cover the floor or ground beneath your project with a drop cloth or plastic sheeting. The drop cloth helps collect any spills and protects the floor.
Ensure you are working in a well-ventilated area. Paint strippers may emit potentially dangerous fumes when emulsifying the sealant. Working in a well-ventilated area will prevent these fumes from saturating the air, keeping you safe.
#2. Clean the wood surface
Working with a clean wood surface will go a long way in ensuring better results. So, wipe the wood with a clean rag to remove dust and debris before applying the tripper.
If you use a damp cloth, let the wood dry completely before proceeding.
#3. Apply the citrus stripper
Once you are ready to apply the stripper, protect yourself with a pair of hand gloves. Paint strippers are strong chemicals that can harm your skin, so you want to avoid contact by all means.
Go for chemical-resistant such as nitrile gloves. Do not use latex for this purpose since it reacts with the chemical.
Additionally, wear a long-sleeved cloth covering your arm beyond the gloves. We also recommend wearing a protective face mask or respirator to keep you from inhaling the fumes from the stripper.
Next, shake the container to mix the contents and then use a paintbrush to apply a thick coat of the chemical to the wood. Ensure you cover every inch of the wood surface with the citrus stripper.
If your workpiece has hard-to-reach areas, you may have to use different paintbrush sizes to reach the tight spots with the stripper.
Alternatively, you can use an old toothbrush to apply the chemical to the hard-to-reach areas. This is an excellent way to avoid spending money on an extra paintbrush.
#4. Give it time to work
Most paint strippers remain active only for a few minutes or hours. However, citrus stripper stays active for up to one day. So you do not have to apply it multiple times to remove the entire finish.
Nonetheless, weather conditions will determine how soon the chemical dries, so consider checking it from time to time.
The citrus striper should work within 30 minutes to 24 hours. Therefore, you can begin to test-scrape the finish after half an hour if you see it bubbling. Still, the more time you give it, the better the results should be.
If you choose to give it up to 24 hours, ensure you cover the surface with plastic to keep it clean and dust-free.
#5: Scrape it off
Once you have given the product enough time to work the poly, use a scraper to remove the softened layer. Both the citrus stripper and the softened coat of polyurethane should come off when scrapping.
Each application of citrus stripper should remove up to five coats of polyurethane. Since most people do not go beyond three coats of poly when sealing wooden surfaces, a single application of the paint stripper should be all you need to get the job done.
You could use a regular putty knife to scrape off the poly and stripper layer, but the metal might gouge the wood. So it is always best to use a plastic putty knife instead.
#6: Reapply the paint stripper if necessary
If you scrape the sealant too soon, some of it may remain on the wood surface. In such a case, you would have to apply another coat of the chemical and allow it to work the leftover poly.
So, inspect the wood surface after scrapping off the poly and removing the residue. If any of it remains on the wood surface, reapply the stripper and give it another 30 minutes to 24 hours or until it forms emulsions.
Next, scrape the leftover poly from the wood and move to the next step.
#7: Wash the wood surface
After removing the sealant, use water and spray soap to wash the wood and remove any debris left behind.
Washing should help remove the grime associated with the dissolved poly and paint stripper. You could also use a dedicated after-wash for even better results, even though soap and water, in most cases, should do the job.
Once done, use a clean towel or cloth to wipe the wood and let it air dry
If you wish to refinish, ensure you prep it with mineral spirits and allow it to dry thoroughly before refinishing.
If you want to stain it before resealing it, follow our guide on preparing wood for staining to walk you through the process.
Method 2. Using baking soda and vinegar solution
Both baking soda and vinegar have numerous uses in our households. Removing polyurethane from wooden surfaces may be one of the less-known applications of these two products that you likely already have in your pantry.
Alone, each product has little stripping effect against dried polyurethane. However, mixing the two products with cornstarch creates a potent polyurethane stripper.
Here are the supplies you will need to use this method:
- Vinegar (1 tablespoon)
- Baking soda (half a cup)
- Stirrer
- Clean bowl (preferably two)
- Hot and cold water (4 cups of hot water and half a cup of cold water)
- Cornstarch (1 cup)
- Scraper
- Hand gloves
- Paintbrush
- Wire brush (or optional sandpaper)
How to remove polyurethane with baking soda and vinegar solution
Check to ensure you have all the supplies above, and follow the steps below to complete the task.
Step 1. Create a mixture of baking soda, vinegar, and cornstarch
Mix about one tablespoon of vinegar with half a cup of baking soda in 4 cups of water to create your baking soda and vinegar solution.
Next, mix one cup of cornstarch with four cups of hot water in a clean bowl to create a paste. Once done, add about half a cup of cold water gradually as you stir with a stirring stick.
After that, transfer the aqueous cornstarch to the first mixture you prepared of vinegar and baking soda. Stir the combination thoroughly until all the ingredients form a uniform mixture.
Step 2. Prepare your work area
Once your homemade poly stripper is ready, lay a drop cloth or plastic sheeting beneath your project to collect any spills.
Wipe the wood to make it dust-free, and proceed to the next step.
Step 3. Use a paintbrush to apply the homemade stripper to the wood
Use a paintbrush to spread the mixture across the wood surface, covering every inch of the sealed area. Let it sit on the sealed wood surface for a few minutes to soften the coat of polyurethane.
Next, use a wire brush to scrub the wood surface with moderate pressure. We recommend using medium pressure to avoid damaging the wood.
Alternatively, you can use a 00-rated steel wool pad for scrapping. Once done, let the wood air dry or dry it with a hairdryer.
Step 3. Sand it
After removing the coat of polyurethane, we recommend sanding the wood to smoothen it. Sanding will also remove any residual debris on the wood, making it smooth and ready for the next coat of finish.
Notice that we are removing polyurethane without sanding, so the sanding in this method is not intended to remove the sealant. Instead, it is a recommended way of prepping the wood surface for the next refinish.
Wire brush leaves the wood feeling coarse, so you need to smooth it with sandpaper.
Consider starting with a coarse 60-grit sandpaper in the direction of the wood grain. Switch to medium 80-grit sandpaper for a smoother feel before finishing it with a finer 120-grit sandpaper for fine sanding.
After sanding, wipe the wood with a clean, dry rag to remove the sanding dust. Alternatively, you can use a vacuum cleaner for the same purpose, whichever you prefer.
Method 3. Using lacquer thinner and denatured alcohol
Both denatured alcohol and lacquer thinner chemically react with polyurethane, weakening its bonds. This makes the two products ideal for removing the sealant without sanding it off the wood surface.
While you could use each product separately to remove polyurethane from wood, they are more effective as a mixture.
The combination is also cheaper and has a less pungent smell than a commercial paint stripper.
Supplies needed
- Lacquer thinner
- Denatured alcohol
- Paintbrush
- Stirrer
- Warm water
- Wire brush
- Clean rags
- Chemical-resistant hand gloves
- Fine steel wool pad.
How to remove poly with lacquer thinner and denatured alcohol
Follow this procedure to complete the task once you have all the above supplies.
Step 1. Prepare the workspace
While lacquer thinner and denatured alcohol are not as strong as commercial paint thinner, they still emit some fumes when mixed. So it is best to work in a well-ventilated space.
Also, consider removing any objects that might stand in your way while you work. This is an excellent way to reduce the risk of accidents.
Finally, cover the floor with plastic sheeting or drop cloth to collect any spills and debris.
Step 2. Prep the workpiece and protect yourself
The stripper needs to go onto a clean surface. So start by wiping dust and debris off the wood surface before using the mixture on it.
Next, protect yourself by wearing a pair of chemical-resistant hand gloves. While denatured alcohol and lacquer thinner are not the most corrosive chemicals, it is best to keep them off your skin. That is where a pair of gloves comes in.
If you have any smell sensitivities, consider wearing a thick face mask or respirator mask. This protection will keep you from inhaling the fumes from the chemical mixture.
Step 3. Create a mixture of lacquer thinner and denatured alcohol
Once your workspace is ready, prepare the stripper by mixing equal parts of denatured alcohol and lacquer thinner in a clean bowl, empty paint can, or plastic container. Your project size should determine the amount of lacquer thinner and denatured alcohol mixed.
Stir the mixture with a clean wooden stick to make it uniform.
Step 4. Apply the mixture to your project
Once the mixture is ready, load a clean paintbrush with it and apply it to the sealed wood. Ensure you cover every inch of the areas where you wish to remove the polyurethane.
Cover the wood with a thick, even coat of the lacquer thinner and denatured alcohol mixture. Consider using two or more strokes in the direction of the wood grain to create the desired thick layer over polyurethane.
Once done, leave it to soak into the poly to soften it for several minutes.
Step 5. Rub it off with a steel brush
After about one minute, use a steel brush to scrape off the mixture along with the softened coat of polyurethane.
The idea is to balance between soaking the poly and avoiding damaging the wood. Thirty seconds to one minute should be plenty of time for the mixture to work without penetrating the wood.
Some people recommend waiting for about 10 seconds. But this may be too little time to adequately soften dried poly, especially if the wood has multiple coats.
When rubbing, ensure you follow the direction of the wood grain, whether you use a wire brush or steel wool pad.
Be patient and go over the wood surface as many times as possible until all the poly has come off.
Step 6. Wash it away with warm water
After removing the sealant and the stripper, use warm water to wash the wood to remove any traces of the mixture.
Consider using wood cleaner along with warm water for the best results. Dry the wood with a clean towel or cloth and let it air dry.
Products to avoid when removing polyurethane from wood
- Trisodium phosphate (TSP)
TSP, or Trisodium phosphate, is a popular cleaning product potent against dust, grease, and grime. However, we don’t recommend it for removing polyurethane since it is not strong enough to remove the sealant.
While TSP does an excellent job of removing dirt from surfaces, it is highly ineffective against dry sealants and will not work against polyurethane.
- Mineral spirits
Like TSP, mineral spirits are used to clean oil-based products off surfaces and tools. However, that is as far as its effectiveness goes. The product will not break the bonds holding dry polyurethane together.
Therefore, it will not dissolve polyurethane and remove it from a wooden surface or any surface for that matter.
- Turpentine
Turpentine is slightly stronger than TSP and mineral spirits. But while it can soften dry polyurethane, it will not dissolve or remove it.
So you can only use turpentine as a half measure, after which you must use another product, such as a paint remover, to get rid of dried poly.
- Goo Gone
You have probably used Goo Gone to remove common household stains from surfaces. However, this stain remover does not soften topcoats.
Therefore, you cannot use it to dissolve polyurethane and remove it from wood without sanding. It simply does not possess that kind of strength.
Tips and tricks for removing polyurethane without sanding
- Always wear chemical-resistant gloves when working with a paint stripper.
- Ensure you follow the instructions on the label when working with any chemical product for removing polyurethane. Where the instructions are insufficient, refer to this guide for detailed help on using the product properly.
- Work in a well-ventilated space whenever you have products that emit fumes. While some fumes are less harmful than others, they can be more dangerous at higher concentrations.
- Wear all the recommended protective gear and clear your workspace before starting your task to avoid the risk of common woodworking injuries.
- Use the recommended after-wash on your paint stripper label to eliminate the foul smell often remaining after the chemical reaction from these products. If the label does not have any recommended after-wash, use mineral spirits instead.
- Use a stronger remover for an older polyurethane coat. For instance, citrus stripper should be more effective against a decade-old poly than a solution of baking soda and vinegar.
- Use plastic scrappers instead of metal ones to avoid scratching or gouging the wood.
FAQs
Can you use vinegar to remove polyurethane?
Yes. You can use vinegar to remove polyurethane from wood as the acid in vinegar breaks down the finish, softening it and allowing you to scrap it off. However, a mixture of vinegar and baking soda is more effective in removing polyurethane than vinegar alone.
What is the easiest way to remove polyurethane from wood?
The easiest and most effective way to remove polyurethane from wood is to use a chemical stripper. We recommend using a citrus paint stripper as it remains active for up to 24 hours, unlike most strippers that only remain active for minutes or a few hours.
Can you remove polyurethane without sanding?
Absolutely. You can remove polyurethane from wooden surfaces without sanding by using commercial paint strippers or homemade products like baking soda and vinegar solution. Apply the solution to the polyurethane and allow it to work for the recommended time, and then scrape it off with a plastic putty knife or wire brush to remove the coat of polyurethane.
How do you remove polyurethane without damaging wood?
To remove polyurethane without damaging the wood, apply your chosen stripper and wait for no longer than the recommended time before scrapping it off with a putty knife or wire brush. Once done, clean the wood with the recommended after-wash or mineral spirits to remove the lingering chemical stench.
If you prefer to sand off the finish instead, here is a video on how to do it safely without damaging the wood:
Final Thoughts on Removing Polyurethane without Sanding
Sanding is a popular way of removing polyurethane from wood. However, knowing how to remove polyurethane from wood without sanding can save you some elbow grease.
This guide provides three tried and tested methods of removing dried polyurethane from wood without sanding to simplify your work. These methods include using the following:
- Citrus stripper and plastic scrapper
- Lacquer thinner and denatured alcohol followed with a wire brush or steel wool pad.
- Baking soda and vinegar solution followed with a wire brush or sandpaper.
The first method is the most effective and recommended for aged polyurethane that has stayed on the wood for several years or over a decade. The last two methods should be effective on newer polyurethane coats.
We hope this guide helps you out. Feel free to share your experience with us in the comments.