How to Clean Polyurethane Brushes

How to Clean Polyurethane Brushes – Polyurethane Removal Methods

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Cleaning up can be a drag. On a good day, cleaning up can feel like a deep meditation; you might put on your favorite music and allow yourself to be completely present in the process. There is something so pleasant about coming home to an immaculate house after work, or a sparkly kitchen before you begin cooking. On the other hand, some things feel tedious to clean and can feel like a frivolous chore. In the world of crafting, cleaning your paintbrushes may be one of them. Imagine your beautiful bristles covered in paint, or even worse, polyurethane, right before you start a masterpiece. In this article, we will discuss how to clean polyurethane brushes and why it is essential. Let us look at why it is such a daunting task in the first place.



Why Is It Difficult to Remove Polyurethane From Paintbrushes?

When learning about how to clean polyurethane brushes, you will soon realize that polyurethane is debatably one of the most versatile materials there. It is used in pretty much every industry on the face of the planet. It can be used as an adhesive, as a protective layer, as a base coat, and can even be used to create resin. Polyurethane is a long-lasting and effective substance. The remarkable efficiency of polyurethane is the fact that once it dries, it bonds to the fibers of the object making it challenging to remove. This is why it is important to know how to get polyurethane off the brush.

Tips for Cleaning Polyurethane Brushes

This is why it is necessary to remove polyurethane while it is still wet. As a crafter, you have likely experienced the frustrating result of having to spend far too much time cleaning your trusty paintbrushes after the polyurethane has dried. It will save you time and money if you get into the habit of cleaning your brushes directly after you use them.

Regularly Clean Polyurethane Brushes

This might not be how you are conditioned, especially after spending hours working on a piece you simply are too tired to continue with. Naturally, the idea of cleaning polyurethane off paintbrushes can feel like a gargantuan task.

Polyurethane Damaged Brushes

The level of difficulty you will encounter when cleaning your brushes will depend on the type of polyurethane you use. If you are using water-based polyurethane, it will be significantly easier to dissolve than if you are using an oil-based polyurethane. Knowing the different types of polyurethane will help you understand how to clean polyurethane brushes better.



Are There Different Types of Polyurethane?

Most crafters use polyurethane as a coat that is either intended to seal their work or protect it. There are minor differences between the type of polyurethane you can get for private and commercial use. The differences are in whether the coatings are oil-based or water-based. Whether you use an oil-based polyurethane or water-based polyurethane, they both serve the same purpose but may differ slightly in strengths and weaknesses. You will also need to learn how to clean oil-based polyurethane brushes because they are cleaned differently to water-based ones. Let us have a look at the two different types you get, and look more closely at their key components.

Different Types of Polyurethane


Oil-Based Polyurethane Coatings

When it comes to the characteristics of oil-based polyurethane, the key component is in the name. It has an oil base. This oil can vary but it mainly consists of either a natural oil or synthetic oil. Oil-based polyurethane has a golden-brown color, and it is this distinctive color that makes it distinguishable from water-based polyurethane. As mentioned before, oil-based polyurethane is much more challenging to remove from surfaces than water-based polyurethane.

The fact that oil-based polyurethane is more difficult to remove is not necessarily a bad thing, considering that it is used to protect your workpiece. It can penetrate and bond with surfaces. This is more easily observable when applying polyurethane on wooden surfaces. Polyurethane coats the wood and makes it resistant to damage that may be caused by heat, moisture, impact, abrasion, and even insect infestation.

Using Oil-Based Polyurethane

Applying oil-based polyurethane may cost more depending on the brand you choose. It takes significantly longer to dry in comparison to water-based polyurethane. Oil-based polyurethane will need fewer coats when applied to protect a surface because it is thick in viscosity. On average polyurethane can take as long as 24 hours to dry. It is advisable to keep your polyurethane surface in a well-ventilated room, or outdoors under cover when it dries. This is because oil-based polyurethane has a strong odor. The fumes can be hazardous and may induce mild side effects from inhaling them.

Oil-Based Polyurethane Fumes


Water-Based Polyurethane Coatings

In the crafting industry, when the topic of protecting your wooden workpieces comes up, traditionally, the number one go-to is oil-based polyurethane. It has long seemed to be the only option for crafters. With that being said, water-based polyurethane coatings are reflectively new. Some people may favor water-based polyurethane, largely based on the notion that this type of polyurethane is more environmentally friendly. Nowadays, environmentally conscious choices of products are becoming more popular as the world shifts into more sustainable living. If oil-based polyurethane coatings are losing their luster it is because they contain substances that are known as volatile organic compounds or VOCs which can be very toxic.

While water-based polyurethane still contains chemicals, it is significantly less than what you would find in oil-based polyurethane. Therefore, the production and use of water-based polyurethane make it the more favorable option.

Applying Water-Based Polyurethane

Water-based polyurethane can take four to six hours to dry, which greatly reduces the time you have to wait before using your item. This is really quick when compared to the twenty-four hours that oil-based polyurethane takes. The faster drying time also means less exposure to harmful chemicals. The finish of water-based polyurethane is clearer because it does not have that yellow oil tint. In addition to all of that, water-based polyurethane is easier to clean or remove with water and a cloth. Water-based polyurethane, however, is slightly more expensive due to supply and demand.

Water-Based Polyurethane Costs More



How to Clean Polyurethane Coatings

We have discussed the different types of polyurethane. You understand that it is important to know the differences in methods and how to get polyurethane off your brushes. We also know why people may opt for one rather than the other. Nonetheless, no matter whether you choose water-based polyurethane or oil-based polyurethane, knowing how to clean them off your brushes is essential. Let us look at different ways you can clean them.

Cleaning Polyurethane Brushes


How to Clean Oil-Based Polyurethane Brushes

The question of how to clean oil-based polyurethane brushes effectively can now be answered. Oil is naturally water-resistant and has an inherent stubbornness when trying to clean it with water off any surface. This is no different when cleaning oil-based polyurethane, but it will be more stubborn than most other substances because it is made to solidify once it is dry. It may require a bit of patience but with guidance, it will not feel so tedious, and your brushes will be clean in no time. Here is a list of things you will need.

  • A small cup
  • Some paint thinner
  • Running water
  • A clean cloth
  • A face mask
  • A well-ventilated workspace
  • Gloves graded for use with polymers
  • A microfiber cloth
  • Dish soap

Paint Thinners for Polyurethane Brush Cleaning

Make sure you have everything from the list above. This will help you clean everything with efficiency. The first step is to fill your cup with water. You should use a cup that will be the same size as your brush. Make sure to fill the cup with water, but not to the brim. You will need to add thinner after you pour the water. Now you have a mix of water and thinner and paint thinner is a great polyurethane brush cleaner! The next step is to put your brush into the cup with your dissolvent. Let your paintbrushes soak. If your bristles were hard when you put them into the cup, after a few minutes, you should be able to bend them again. Make sure you do not get any of the mixtures onto your work surfaces. You might have a difficult time fixing the affected areas after.

Mineral Thinners Cleans Polyurethane

Once you can comfortably bend the bristles of your brush, continue to do so. Bend the bristles back and forth. You will see the bubbles form around them. These bubbles mean that the polyurethane is starting to dissolve from the bristles. After some time, you should see that the paint thinner will change color. This happens after the saturation from the polyurethane neutralizes. When the thinner is clear, you can take the brush out from the cup.

Flex Brush During Cleaning

After you have removed the brush from the thinner. You should place your brush under warm water. Make sure you have your gloves on before you do the next step. You need to add soap to your brush. Slowly rub the soap into the bristles. A great tip is to gently rub the brush against your hand so that the soap activates, and you start to get into and under the layer of oil on your bristles. You can also carefully rub the bristles in between your fingers, but you want to be careful not to damage them.

Washing Polyurethane Brushes

Run the brush underneath the warm water, do this until the brush is completely clear of soap and residue. Do it thoroughly so that you do not have to repeat the process of soap and warm water. Check your brush for the final time before using the microfiber towel to wipe the brush until it is dry. Your brush should be completely clear of oil-based polyurethane now. Make sure you do this every time you use polyurethane, ideally before it dries and hardens.

Rinse Brush in Hot Water


How to Clean Water-Based Polyurethane

As we discussed earlier in the article, water-based polyurethane is generally the more popular option amongst crafters. One of the reasons for that is because it takes less time to dry, but also less time to clean. There is still a method you should use to ensure that you get the most thorough clean for your brushes. Now, before we look at exactly how you can clean your brushes of water-based polyurethane, here is a list of what you will need to clean water-based polyurethane.

  • Some water
  • A small cup
  • A source of running water
  • Gloves graded for use with polymers
  • A face mask (fabric or otherwise)
  • A well-ventilated workspace
  • A clean cloth

Now that you know exactly what you will need, let us look at how to clean water-based polyurethane from your paintbrushes. Water-based polyurethane is much less of a chore to clean than oil-based polyurethane. You do not need a polyurethane brush cleaner, like paint thinner. This is because water-based polyurethane is different to oil-based polyurethane in that in order to break down the oil, you have to use thinners and soap to clean the bristles. With water-based polyurethane, you only need water. When you immerse it in water, it disturbs the chemical balance of the bond. Slowly releasing the bristles.

Water Cleans Water Based Polyurethane

When building the habit of cleaning your brushes before they dry, you could find yourself becoming a bit impatient. Always remind yourself that prevention is better than the solution, especially when you know for a fact that cleaning them once dry will either result in you throwing your brushes away or spending way too long cleaning them. Your patience will be rewarded with a beautifully clean polyurethane brush.

Clean Paint Brush Bristles

Much like the process of cleaning oil-based polyurethane off your brushes. You must fill your cup with water. Then you need to place your brushes into the cup and allow them to soak for a couple of minutes. You will notice that the water will begin to change color. It will become a murky gray color from the polyurethane dissolving. When you see the water change to this color, you must repeat the process. Empty the murky water and replace it with clean water. It is a bit of a repetitive process, but you need to do this until the water remains clear.

Soaking Dirty Polyurethane Brushes

When the water is clear after soaking, you can be sure that the majority of the polyurethane has been removed from your brush. Once removed, you need to run your brush underwater. For water-based polyurethane, you do not need warm water. Cold water will do the job, it is also better for the bristles on your brush. So better take advantage of the opportunity, since this whole process is to maintain the new condition of your brush.

Rinse Clean Brush in Cold Water

It is best to wear your gloves for this process. Run the water over your brush’s bristles and use your hand to rub off any polyurethane that may still be stuck to your brush. Polyurethane contains harmful chemicals, so refrain from touching your face and eyes. The best part about water-based polyurethane is that all you need is water to clean it. Use your clean cloth to dry off in residual water, and then you are done.




How to Store Polyurethane Brushes

The final step you need to know for maintaining your brushes in the process of using and cleaning the polyurethane is storing them. It is important to understand how to store polyurethane brushes between coats and after use. This is probably the easiest but still essential. Something to consider before unnecessarily cleaning your brushes is whether you will be needing it again within a short period. In that case, you can simply leave your brush in polyurethane. It is the best way to store your brush while you are still working.

Storing Polyurethane Brush Between Coats

While you work, you can take a 15-minute break and your brush will still be ok to use. During your short break, ensure that your brush is only about a third of the way in the water. You do not need to put the whole brush into the water. If you need to stop using your brush for a longer period, then you need to prevent it from drying out. The best way to do this is to clean your brushes using the methods above. Another temporary solution for how to store polyurethane brushes between coats is to wrap your brush in foil or plastic, then store it in a cool place.



Even though this entire process may seem like a giant task to simply maintain your brushes, remember that it is going to save you time and money down the line. With practice, it will become second nature. You now have all the information you need to clean polyurethane off your brushes. You understand the different types of polyurethane, and the exact process to clean them. Using polyurethane on your workpieces will be a breeze, just ensure you protect your skin, avoid eye contact, and work in a space that is ventilated.



Frequently Asked Questions


How to Clean Stain Brushes Without Paint Thinners?

The easiest and most efficient way to remove stains without thinners is to follow the same process as you would with oil-based polyurethane. Make sure to soak the brushes until the polyurethane begins to dissolve, then you can soap and lather. Repeat this process until the stains have been removed. It is entirely possible to learn how to clean stain brushes without paint thinners!


How to Clean a Paintbrush With Mineral Spirits?

Mineral spirits are a sufficient polyurethane brush cleaner. Some crafters prefer to use mineral spirits instead of using paint thinners. If you prefer mineral spirits, the process is the same. You allow your paintbrush to soak in the mineral spirits until the bristles soften, and you can separate them. You then rinse the bristles, brush them against your gloves underwater until you cannot see any residual polyurethane. Once you have done this, you can use a microfiber cloth to dry your brushes. So, if you were wondering how to clean a paintbrush with mineral spirits, wonder no more!


Are Mineral Spirits and Brush Cleaner the Same?

When comparing mineral spirits and paint thinner, they are very similar. One works just as well as the other. However, paint thinner is considerably cheaper to use, so you may as well use paint thinner instead of mineral spirits. Just do your best not to inhale it.

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