Polyurethane is widely used on wood to prolong and preserve its life. Moreover, it brings
out the natural color of the wood grain and gives it a smooth, glossy finish. Polyurethane
may get scratched and damaged over time and you may want to repair or stain the wood. For that, you need to know how to remove polyurethane from wood.
You can remove polyurethane from wood by using chemical strippers or sanding. Sanding takes a lot more time and effort, plus it’s messier than using harsh chemicals. Chemical stripping does the job easily but you need to be careful using and handling the chemicals during the process. You can also try vinegar and baking soda if using chemicals to remove polyurethane is not to your liking.
What Is Polyurethane?
Polyurethane is a liquid coating that may be applied to wood to create a protective layer. This layer provides protection against moisture and other damaging elements. After drying, it transforms the wood’s surface into a durable and easily cleanable surface that can last a long time.
Polyurethane is more like liquid plastic. It can be applied over existing acrylic or latex paint. And can be satin to shiny, based on different varieties.
Applying polyurethane can increase the durability of the existing coat of paint. However, oil-based polyurethane can add a yellow hue and change the color of the paint slightly. That’s why water-based polyurethane is recommended to avoid tinting the paint.
Types of Polyurethane
As mentioned earlier, polyurethane comes in two main types: water-based and oil-based. There is also another type which is a mix of both types.
The types are differentiated based on durability, composition, drying time, odor, etc. The polyurethane that has an oil-based formula is resistant to water, as well as alcohol and various acids.
On the other hand, the water-based formula is quite opposite, as it’s resistant to neither alcohol nor acid. Water-based polyurethane has lower levels of volatile organic compounds compared to oil-based ones.
Here you can see the general differences between water-based and oil-based polyurethane types.
| Water-based Polyurethane | Oil-based Polyurethane | |
| Flammability | Inflammable | Flammable |
| Durability | Good | Excellent |
| Cleaning Agents | Water and soap | Mineral spirits |
| Dry to Touch | 10-20 minutes | 2-6 hours |
| Toxicity | Low | High |
| Odor | Low | High |
Water-based Polyurethane
Water-based polyurethane is one of the most popular choices as it has a low odor and low toxicity. However, it does not fare well against excessive heat and solvents or other chemicals. Therefore it’s not a good option for places to rest pans or other hot objects.
It is better suited for picture frames, bookcases, dressers, desks, chairs, and similar items which are not in contact with cleaning chemicals or direct sun rays. Plus, water-based polyurethane stays clear after application and doesn’t become yellow as it ages.
Oil-based Polyurethane
Oil-based polyurethane is a mixture of organic compounds and finishing oils that create a double coating. It is usually resistant to water, alcohol, and other acids. As it’s generally more durable, it is more resistant to heat and chemicals as well.
Because of this, oil-based polyurethane is often used in the kitchen, especially for countertops or tabletops. It brings out the natural richness of grain and the color of the wood. The only downside of this type of polyurethane is that it becomes yellow over time.
Water-based Oil Modified Polyurethane
There is another type of polyurethane that is a new addition to the market. It is called water-based oil-modified polyurethane. It has the durability of the oil-based type while having the ease of cleanup of the water-based type.
Preparation and Precaution Before Removing Polyurethane
Prepare the Area
First, you should prepare the area you are going to work in.
Cross Ventilation
Removing polyurethane from wood is a lengthy and demanding process and you should do it in a well-ventilated area. Better if you can work outside but in case you can’t, you should try to create cross ventilation in the area you’re working. Open the doors and windows of the room so the chemicals and fumes won’t be stuck inside.
Clean The Work Area
Before starting work, you should clean the work surface. Either by using a vacuum or using wet or dry clothes, you need to get rid of the dirt from the surface.
Cover The Area
If you’re working inside a room, it’s better to move the furniture to another room or in
the garage. If that’s not possible, at least cover the other furniture with clothes or plastics. Similarly, you need to protect the floor where you’re working from strippers. You can cover it with drop cloths or newspapers or even a tarp.
Wear Protective Gear
If you are using chemicals to remove polyurethane, you need personal protective gear.
- Long pants and long-sleeved shirts and closed-toed shoes
- Chemical-resistant gloves to avoid contact with the skin
- Chemical splash goggles for eye protection
- A mask or a ventilator to protect throat and lungs
Choose the Paint Stripper
After preparing the work area, you should choose the paint stripper you want. Chemical-based paint strippers are very effective for removing polyurethane. However, they can be pretty harsh on the skin and can cause respiratory problems if you are not careful.
That’s why you need to work in a well-ventilated room and wear safety gear before using chemical-based strippers. On the other hand, if your work area has poor ventilation, you
should use water-based strippers. They may take much longer to work but you will be safe from strong chemicals.
Recommendations for Best Polyurethane Remover
DUMOND Strip Advanced Paint Remover
The Smart Strip Advanced Paint Remover offers the best results when getting rid of polyurethane from wood. If you’re concerned with chemical use, no need to fret, as this product is water-based and 100% biodegradable. It does not contain any harmful chemicals like NMP or methylene chloride.
Not just being environmentally friendly, it is also fast and effective in removing multiple layers of paints, varnish and coatings from wood. Moreover, this pH-neutral paint stripper does not require any post-strip neutralization. You can simply just apply, let it set and wash off.
Pros
- Professional strength and highly effective
- Non-toxic, non-caustic, odor-free
- Removes up to 15 coats at a time
- Safe to use biodegradable formula
- Good value for money
Cons
- Doesn’t offer great coverage
SUNNYSIDE CORPORATION 2 Minute Remover Advanced Gel
The 2 Minute Paint and Varnish Remover is one of the fastest when it comes to removing polyurethane from wood. This remover can quickly work even on multiple layers of polyurethane and just with a single application.
This advanced gel features a new non-flammable formula that is free of methylene chloride and thus safe to use. You can use this on vertical surfaces as well as horizontal surfaces. Just a one-gallon container can cover up to 100 square feet of surface area. Not only wood, but you can also effectively use it on a variety of other surfaces and remove lacquer, oil-based paint, varnish, shellac, epoxy and polyurethane finishes.
Pros
- New and safer formula free of methylene chloride
- No damage to wood, metal, masonry, marine, or automotive finishes
- Removes multiple layers of paint or varnish in one application
- Excellent coverage on vertical and horizontal surfaces
- Budget-friendly
Cons
- Using it can be messy
SUNNYSIDE CORPORATION Hi-Speed Ready Strip Paint and Varnish Remover
What’s more convenient than a trigger spray! The Hi-Speed Ready Strip Paint and Varnish Remover is sure to be the quickest and most convenient way you can remove polyurethane from wood.
For people who want to get the removal job done fast without a paintbrush, this trigger spray remover is the answer. This product offers a safer formula that is both low in odor and environmentally friendly. The no-drip formula is easy to apply on vertical surfaces. Besides, it starts to work in 30 minutes and stays wet longer. You don’t need to worry about clean-up either as you can simply take care of it with just water.
Pros
- No-drip formula for quick and easy removal
- Fast-acting stripper starts working in about 30 minutes
- Suitable to use on masonry, wood, metal, brick and concrete
- Capable of removing up to 3 layers of oil or water-based paints
- Affordable and budget-friendly option
Cons
- Takes longer time to work compared to strong chemicals
How to Remove Polyurethane from Wood
One of the best methods to remove polyurethane from wood without damaging the stain is to use a chemical stripper. Whether you remove polyurethane from furniture, doors, or flooring, the process is more or less the same.
As you will be working with chemicals, make sure to do it in a we-ventilated room and armed with proper safety gear.
Things You’ll Need
- Chemical paint stripper
- Plastic scraper
- Paintbrush
- Orbital sander
- Sandpaper
- Wire brush
- Water
Step 1: Apply the Stripper
First, make sure the paint stripper is sealed properly and give it a good shake to mix it well. Then pour it into a bucket and use a paintbrush to apply the stripper to the wooden
surface. Coat it in a thick layer and cover all areas. Use the tip of the paintbrush to apply corners and hard-to-reach areas. Wait for 15 minutes or more for the stripper to dry properly.
Step 2: Scrape the Polyurethane
After the surface is all dried out, it’s time to remove polyurethane. Scrape in the direction of the wood grain to keep the damage minimum with the scraper. It’s better to use a plastic scraper rather than a metal one as it’ll be less abrasive on the wood. You can also use a small wire brush to remove polyurethane from hard-to-reach areas.
Step 3: Sand the surface thoroughly
Next, to make sure there is no residual polyurethane left behind, you should sand off the surface. It’ll also give you a fresh layer to work with. Run the sander over the wood surface
using 150-grit sandpaper. Later, switch to the 220-grit sandpaper for a polished and smooth finishing.
Step 4: Clean Up the Surface
Finally, clean the surface of the wood with water and let it dry. After the wood is completely dry and clean, you can refinish the wood with a new layer of varnish, paint, or stain.
How to Remove Polyurethane from Wood without Chemicals
If you do not feel comfortable using strong chemicals to remove polyurethane from wood, there are other options available. It’s ok to prefer a more natural alternative instead of using harsh chemicals.
An easy and cost-effective option is to use homemade remedies like water, baking soda, vinegar, etc to remove polyurethane from wood.
Just remember one thing before using baking soda and consider this as a word of caution. Tannin levels in different wood types vary, but woods with high tannin levels may have a chemical reaction when it comes in contact with baking soda.
As a result, you will not be able to remove polyurethane from the wood well and may end up staining your wood. Oak, cherry, mahogany, maple, etc tend to have higher tannin levels compared to pine which has lower tannin levels. So, it’s better to use another method to remove polyurethane if you have any of these woods.
Things You’ll Need
- Vinegar
- Baking soda
- Water (hot and cold)
- Cornstarch
- Wire brush or steel wool pad
- Paintbrush
- Cup and bucket
After collecting everything you need, follow these steps to remove polyurethane:
Step 1: Prepare the Removal Mixture
To make the mixture you need the following:
- 4 cups of hot water
- 1 cup of cornstarch
- ½ cup of cold water
- ¾ cup of baking soda
- 1 tablespoon of vinegar
Put all the ingredients in a bucket and mix them thoroughly. Keep the paste ready to apply to the wood.
Step 2: Apply the Mixture
Apply the mixture to the wooden furniture using a paintbrush. Coat the surface with a
thick, even layer and leave it. Give it 5-10 minutes for the mixture to dry and soak into the wood.
Step 3: Scrub the Surface
Next, scrub the furniture with a wire brush or a wool stripping pad. Don’t be hesitant to put some pressure on as you will not be damaging the wood. Keep scrubbing until there is no slick feeling on the surface. That means you’ve been able to completely remove the polyurethane.
Step 4: Sand the Wooden Surface
When your furniture no longer feels slick means it’s time to sand. For that, you’ll need various sandpapers such as 60, 80, and 120 grits.
Start with the 60-grit sandpaper in the direction of the wood’s natural grain to avoid damage. Continue sanding till you remove all the color from the wood and can see the natural color. Now use the 80-grit sandpaper to smoothen the wood. And then use the 120-grit sandpaper for a final finishing touch. Keep sanding until you reach the desired smoothness.
Step 5: Clean the Surface
After finishing sanding, wipe the wooden surface with a dry, clean cloth to remove any remaining sawdust. Once the surface is thoroughly cleaned, you can varnish or stain or refinish your furniture.
How to Remove Polyurethane from Wood without Sanding
If you don’t want to sand off your wood to get rid of polyurethane, there is another way to remove it without sanding. For that, you’ll need denatured alcohol and lacquer thinner which will do the job quickly and efficiently.
Things You’ll Need
- Denatured alcohol
- Lacquer thinner
- Stirring stick
- Steel wool pad
- Bucket
- Paintbrush
- Wood cleaner
- Warm water
Step 1: Create A Mixture of Denatured Alcohol and Lacquer Thinner
Pour an equal amount of denatured alcohol and lacquer thinner into an empty bucket. Stir the mixture thoroughly using a wooden stick. The lacquer thinner will help to dissolve the paint and varnishes, while the denatured alcohol will act as a cleaning agent. The mixture will remove polyurethane from the wood but it’s not strong enough to damage or affect the wood.
Step 2: Apply the Mixture to Remove Polyurethane
Check if the mixture is consistent and if no patches of the two solutions showing. Now, apply the mixture to the wood using a paintbrush. Coat it evenly and thickly to cover each area two or three times. For complete coverage, overlap brushstrokes if necessary.
Step 3: Remove the Mixture Using Steel Wool
After applying the mixture, wait for around 10 seconds, and let it soak into the wood. Then take a steel wool pad and use it to remove both stripper and polyurethane. Rub the steel wool pad in the direction of the grain. Keep working the area several times until the wood is completely stripped off.
Step 4: Wash and Clean the Wood
Now that the polyurethane has been stripped off, you need to clean the wood. Use a wood cleaner to remove any extra dirt or remaining residue. Then wash the wood with warm water and dry the surface with a soft, clean cloth.
Can You Sand Off Polyurethane
Yes, you can remove polyurethane by sanding.
Many people wonder whether it’s ok or not to sand off polyurethane from the furniture. Some are concerned with using harsh chemicals to remove polyurethane and look for alternatives. Sanding can definitely help you in this regard.
However, sanding is one of the most labor-intensive ways to remove polyurethane. It requires high energy and probably won’t be enough to completely strip off polyurethane from the surface. That’s why most people use sanding to remove residual polyurethane after initially removing it with chemical strippers.
Sanding can be used to remove almost all wood finishes. So, if you are not sure whether you are dealing with polyurethane or another varnish, better to sand off the finish rather than use chemicals.
The safest way you can do sanding is if you use sandpaper on a sanding machine. You can use 120-grit sandpaper or 150-grit sandpaper to remove any excess coats of polyurethane from wood. It’s best to begin sanding with the heaviest grit sandpaper. That way you’ll eventually get a way smoother surface.
FAQs
Can you sand polyurethane off wood?
Yes, you can remove polyurethane from wood using sandpaper. It takes a huge amount
of effort to sand off completely. Better to use chemicals or other varnish removers first to remove polyurethane, and then sand off the wood to remove the remaining residue.
Does vinegar remove polyurethane from wood?
Vinegar certainly removes polyurethane from wood as its PH level of 2.4 acts as an acid. However, it doesn’t work as well as a chemical remover and takes more effort. It’s a good choice if you’re concerned with safety and do not want the hazards of using strong chemicals and fumes.
How do you get polyurethane off skin?
In case you have managed to get polyurethane on your skin, try rubbing natural oil on dried polyurethane. You can try vegetable oil or peanut butter as they are more effective and safer for the skin. This will loosen and lift the polyurethane from your skin.
Will mineral spirits remove polyurethane?
Usually, mineral spirits soften a natural varnish finish and it can be just wiped off. But mineral spirits don’t affect polyurethane much. You will need a paint stripper thinned with solvent to get the work done.
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