Most materials used in polyurethane finishing or refinishing are not reusable. Of course, if you can reuse any of the staff in this process, that’s a cost-effective bonus for you. And, application tools such as brush or sprayers are probably the only things that can last a long for further use if properly cleaned and maintained. But if you don’t know how to clean polyurethane brush or sprayer, you’re just wasting the money in vain.
In this article, we shall discuss all about cleaning polyurethane brush, leaving the sprayers for another topic of discussion. Following steps are how to clean polyurethane off brush in brief:
Oil-Based Polyurethane Brush Cleaning
- 3/4 cups
- Mineral spirits (you may take Paint Thinner or Turpentine following the instructions from poly can)
- Tap water
- Dish soap
- Scrub brush (nylon is better)
- Gloves (1 pair, not mandatory)
Step 1: Pour Mineral Spirits
Take mineral spirits and pour it into 3 or 4 cups. Make sure each cup holds enough spirit to submerge the brush you are going to clean unless ferrule.
Step 2: Submerge the Brush into Mineral Spirits
Take the brush having polyurethane and submerge it into the mineral spirits of first cup. Hold it there for some time to cover all the bristles. Then, stir the brush some time bending it over across the cup so the bristles are completely soaked.
Step 3: Take the Brush into the Next Cup
When the mineral spirits turns into dark brown color, take the brush into next cup. Repeat the process explained in step 2 in rest of the cups. Wait patiently in every cup until the color is changed. You may require maximum five minutes in every cup to get the brush is ready to move into the next cup. Three or maximum four cups of mineral spirits should be enough to reach the point where color no longer changes despite slushing the brush around in the cleaning agent.
Step 4: Put the Brush under Tap Water and Scrub
No more polyurethane should be there after first three steps, but you still should wash the brush thoroughly using tap water. Rinse the brush under running tap water and apply dish soap using the Nylon scrubber. It would be better if you apply your fingers in-between brush bristles and scrub it as much as you can using your hands. You may need to repeat the process more than once to get a clear lather from the brush.
Step 5: Scrub using a Nylon Brush
The hand scrubbing should be enough to remove oil-based polyurethane from the brush. However, if it still seems a little oily, it is time to apply a little soap on it again and scrub gently with a nylon scrubber and rinse under the tap water. With this, the bristles will be completely oil-poly free and clean.
Step 6: Dry the Brush
All is done. Just hang the brush over a place where the water drops will be sucked or drained well. It is better if there is airflow, and the brush shall be ready to use next day.
Water-Based Polyurethane Brush Cleaning
As water-based polyurethane is dispersible into water, so while cleaning the brush you won’t be encountered by any sticky or oily substance like an oil-based one does. You can simply put the brush (with waterborne poly) under the running tap water and scrub continuously until the polyurethane is cleaned off. The process should be very easy and less time consuming.
However, if you need a formal description on how to remove water-based polyurethane brush, the following should be fair enough:
- 2 or 3 cups
- Tap water
- Dish soap
- Gloves (1 pair, not mandatory)
Step 1: Take Three Cups of Clean Water
Step 2: Submerge the Brush into the Cup Water and Stir for 3 Minutes
Step 3: Move the Brush on to the Next Cup of Water and Repeat Stirring
Step 4: Wash the Brush with Dish Soap Under Running Tap Water
Step 5: Put or Hang the Brush to Dry
Why do You Need to Clean a Polyurethane Brush?
Cleaning a polyurethane brush is a necessary part of paint maintenance. Whether water or oil based, polyurethanes chemicals generally contain VOCs at a certain level. Naturally, the brush used to apply those finish carry harmful substances unless cleaned properly. And, if you want to use a polyurethane brush over and over again, you need to clean it every time after use and maintain it very well.
If the polyurethane being applied is not an waterborne one, you can use mineral spirit after the final coat. You will need to use mineral spirits in a well-ventilated room and make sure that you are working in a well-ventilated space. The mineral spirits should be applied only to the bristles of the brush covered with polyurethane. Never put the ferrule or metal portion of the brush in the liquid.
If you don’t want to purchase new brushes every few months, you can purchase a high-quality brush that won’t wear out. The best way to keep your polyurethane brush in top shape is to clean it regularly. By using a dry rag to wipe down the brush, you can prevent mold and mildew from forming. By cleaning the brush regularly, you can ensure its longevity for years to come.
Cleaning Polyurethane Brush without Mineral Spirits
To clean a polyurethane brush without using mineral spirits, you first make sure whether it is oil or water-based. If waterborne poly, you don’t need to use mineral spirit. Just use water and soap, good enough to soften the polyurethane and remove it from bristles. However, you cannot wash a brush containing oil-generated poly with soap and water, because the formulation does not permit cleaning using only soap and water. Moreover, they toxic and are not intended to be flushed into the sewer system.
Mineral spirit is the most preferred chemical to clean that polyurethane. But, you may apply thinner or turpentine instead of mineral spirit. Vinegar is another option that can remove polyurethane, so you consider that too. Considering vinegar is alcohol-based [made by fermenting alcohol (ethanol) with acetic acid bacteria], it can easily remove oil-generated polyurethane. Follow the simple way of cleaning oil polyurethane given above and ensure your rinse the brush finally with water to maintain the integrity of the bristles.
Can You Use Acetone to Clean Polyurethane Brush?
Acetone is a naturally occurring paint thinner that can be used to clean paintbrushes of both water and oil-borne polyurethane. Acetone, however, should solely be used to clean polyurethane brushes. Adding any other cleaning agent to it may simply bring damaging result.
Can I Use the Same Brush for Waterborne and Oil-Generated Polyurethane?
The answer to this question depends on your preferences and materials. But in a nutshell – yes, you can use one type of polyurethane brush for other type. As long as the bristles are intact, you can keep using the brush for either waterborne or oil-based polyurethane applications, subject to perfect cleaning and maintenance.
Should You Clean Polyurethane Brush Between Coats?
You may be wondering whether you should clean your polyurethane brush between coats. You don’t need to clean the polyurethane brush between coats. While this is important for maintaining the brush’s condition, it is unnecessary for the paint to adhere to the brush between coats. To keep the brush in its best condition, you can seal it in a plastic bag and refrigerate it for a few hours. This will help keep the brush fresh and ready for the next coat. But still, if you want to clean the brush between coats, you are free to do.
Knowing how to clean polyurethane from a brush will save you time and money in the long run. A properly cleaned brush will save you time and money, and it will last for many years. Cleaning tools properly will also ensure your brushes remain effective and professional. You can also choose the best cleaning solution for your painting project based on its material. Once you get used to it, this will become second nature to you.