Polyurethane is a popular wood finish available in oil-based and water-based options. They are available in a variety of finishes, including glossy and satin. We use different methods when applying polyurethane fish on beautiful woodwork. No matter what method you use, mistakes can occur during or after application. I have made many mistakes when applying polyurethane varnish. I found solutions to all my mistakes when I applied polyurethane. So, How to fix Polyurethane mistakes?
Here’s what I know from being a woodworker for several years:
Most of the polyurethane mistakes can fix by sanding, re-application of the polyurethane finish, by using quality, a new can of polyurethane finish, not subjecting polyurethane can to extreme weather, cleaning the surface well before applying polyurethane, and following proper guidelines when applying polyurethane coats.
But these aren’t the only solutions that can fix polyurethane mistakes. These are common problems and mistakes in polyurethane.
- Bubbles in polyurethane finish
- Puddles in polyurethane finish
- Uneven polyurethane finish
- Separating issue
- Discoloration of polyurethane
- Surface roughness
- Orange peel effect
- Streaking
- Alligatoring
- Cratering
- Cloudy polyurethane finish
- Scratches in polyurethane finish
- Blushing
- Polyurethane runs
- Trapping insects and dust in polyurethane finish
So, in this article, we’ll deep into every single mistake mentioned above and talk about how to fix polyurethane mistakes. By the time you’re done reading this article, you’ll have no doubt about how to fix the polyurethane finish.
You’ll also have some cool techniques to use when applying polyurethane finish to your next woodwork without making any mistakes.
Just keep reading!
36″ x 12″ shelves for consoles. Cut, sanded, stained, and hit with a nice coat of thegoneapp.com these are up, I’ll have only two more 12 foot shelves to thegoneapp.com game room is coming together! #gameroomgoals #buildingagameroom thegoneapp.com/HZo6xGE8wM
(*15*)1. Bubbles in Polyurethane Finish
Bubbles in polyurethane finish can occur due to various reasons. The most common reasons for bubbles in polyurethane finish are,
- Shaking the polyurethane can properly before use.
Air can build up in the polyurethane if it is not shaken before use. The trapped air could cause bubbles when the polyurethane is applied. It can be difficult to avoid.
- Wipe brush with the side of polyurethane can
By wiping the brush along the side of the polyurethane can, air bubbles can trap inside the brush fibers. When these air bubbles are mixed with polyurethane, they can form permanent bubbles in a finish polyurethane.
- Poor surface and brush preparation
Before applying polyurethane finish, you need to clean the wood surface and also prepare the brush by soaking the brush in the solvent. If you do not, air bubbles may build up between ferrules or bristles.
- Not using the correct brush type
By selecting the wrong brush type, won’t do the job smoothly and doesn’t go well with a polyurethane finish. Brushing will become difficult if the application surface isn’t compatible with the brush type. This can lead to bubbles.
Help! @MinwaxCANADA Polyurethane for floors has tiny bubbles all over! We followed the instructions. How can we fix it? thegoneapp.com/7l1tWJdvyx
How to Fix Polyurethane Bubbles?
Here is how to fix polyurethane foam bubbles after application of polyurethane.
- Stir the can without shaking
You need to stir the polyurethane can before use without shaking rapidly. By stirring, not only you’ll get a uniform composition of polyurethane all over the can, but also no air bubbles will trap inside.
- Clean the surface
Cleaning the surface before applying a polyurethane finish is a must. It is a good idea to sand the surface before applying the first polyurethane coating. Before wiping the surface with a cloth, you need to dip it in mineral oil (if you’re using oil-based polyurethane) or alcohol (if you’re using water-based polyurethane). By wiping the surface with a dipped cloth, air bubbles that are trapped inside the surface will remove and don’t occur polyurethane bubbles after the application is done.
- Apply thin coats
Never go for thick coats, because they not only have long drying times but also have enough rooms for air to trap inside while applying. Thin coats are best.
- Tap on bubbles before it dries
Once you apply the polyurethane finish, if you notice the bubbles are occurring, gently tap on bubbles using the top of your brush until they flattened up. This is only possible after your finish has dried. Tape is not recommended after the finish dries.
Hardwood floors can be difficult to maintain. The worst thing about polyurethane is bubbles. #hardwood #flooring thegoneapp.com/PpPPnwIn6M
- Sanding after it dries
If you notice bubbles in the polyurethane finish after it is completely dried, the only option you can go to do the sanding until bubbles go and reapply the polyurethane coat in a proper method to avoid bubbles.
(*15*)2. Puddles in polyurethane finish
After the final finish was done, most of the people notice puddle marks in the polyurethane finish. Puddles can also occur for a variety of reasons, just like bubbles. So, let’s talk about what are the reasons for puddles in polyurethane finish under how to fix polyurethane mistakes.
Causes for Puddles in Polyurethane Finish
- Apply another coat of polyurethane before the previous layer dries completely.
You must wait until the first coat is dry before applying the second coat. If you do not wait until the finish is dry, puddle marks may form. These cannot be reversed.
- Application of thick layers
By applying thick layers of polyurethane, the puddles can easily occur, because you cannot apply a uniform layer throughout the surface. There will be places that are thinner than others, which can lead to puddles.
How to Fix Polyurethane Puddles?
- Wipe with rag-soaked mineral spirits
If you notice puddles in polyurethane finish, I highly recommend wiping your oil with a rag soaked with mineral spirit.
- Before you use water-based polyurethane, wipe it off with a damp towel.
- Use mineral spirits to clean off any oily residues before they set.
You need to work quickly with water-based polyurethane.
- Sand and start over
If you couldn’t wipe the surface before it completely dry, sad to say, you need to do the sanding again completely and reapply the polyurethane coats. Make sure you apply thin layers of polyurethane and wait several days before applying your next coat.
(*15*)3. Uneven Polyurethane Finish
Getting even a polyurethane finish is a crucial task. The causes of uneven polyurethane finish are because of,
- Insufficient mixing
- Contaminated polyurethane
- Improper sanding and cleaning the surface
- Uneven application of polyurethane finish
Warned customer that a light stain might have the floors uneven. My standards were not met by the polyurethane used so I sanded it again on my own dime, and she chose a darker shade. Now, the floor matches the cabinets. It is slightly darker. thegoneapp.com/CKklZ4U5MN
How to Fix Uneven Polyurethane Finish?
You can only fix an uneven polyurethane finish by sanding it and starting again. Below are the steps to achieve an even finish to your polyurethane.
1.Sanding
Sand the whole surface with a fine-grit sandpaper. Don’t sand too hard because it can damage the surface easily.
2. Cleaning
Wipe the surface using a clean cloth to remove dust and debris. It’s a problem that can cause a lot of damage to surfaces.
3. Application
Get a soft brush and apply polyurethane finish smoothly with uniform thickness all over the surface. Apply thin coats. Before applying the second coat, wait until the first coat is dry completely. Likewise, I recommend going at least 3 coats to get the finish that you wish. If necessary, sand each coat.
(*15*)4. Separating Issue in Polyurethane Finish
If you notice the polyurethane coats that you apply separately over time, that can happen because of the following mistakes,
- Polyurethane finish is not mixed properly
- Polyurethane is contaminated
- Product is expired
- The surface wasn’t clean between each coating
- Wood is oily and doesn’t bond well with the finisher
- Due to the application of thick layers
How to Fix Separation of Polyurethane Finish?
For a solution to a separation problem in polyurethane paint finish, you must sand everything and start over with a brand new polyurethane coat from another manufacturer. Here I have listed the steps you need to follow,
1.Sanding
Sand the whole surface with a fine-grit sandpaper. Don’t sand too hard because it can damage the surface easily.
2. Cleaning
Wipe the surface using a clean cloth to remove dust and debris. After each coat is applied, clean the surface with a clean cloth. Be sure to let the coat dry completely before you wipe it off.
3. Application
Get a soft brush and apply polyurethane finish smoothly with uniform thickness all over the surface. Apply thin coats. Before applying the second coat, wait until the first coat is dry completely. Likewise, I recommend going at least 3 coats to get the finish that you wish. If necessary, rub sand between each coat.
By following the above 3 steps properly, you won’t get any separation issues after the application of the polyurethane finish.
(*15*)5. Discoloration of Polyurethane
Yellowing polyurethane is a natural process rather than consider a mistake. Once you apply polyurethane finish over your hardwood, you’ll notice it turns yellow over time. You can avoid yellowing by taking care.
The main causes of discoloration of polyurethane finish are,
- UV rays from the sun
- Using Oil-based polyurethane finish
- Moisture
- Minerals
The above factors cause the discoloration of polyurethane and there are several things you can do to fix this.
I painted the trim and banister in the same bright color, but added polyurethane to the banister. It began to yellow. thegoneapp.com/ZujueDxJi8
How to Fix Discoloration of Polyurethane?
Polyurethane can be prevented by periodically sanding off and reapplying the polyurethane. Proper shading can also be a good option. I highly recommend going with water-based polyurethane because it doesn’t discolor like oil-based polyurethane.
Also, don’t forget to go with thin coats with each layer.
(*15*)6. Surface Roughness of Polyurethane Finish
The surface roughness can occur because of following reasons,
- Insufficient preparation
If the surface is not cleaned properly before applying polyurethane finish, the surface will be rough when it is dried due to dust and debris.
- Contaminated product
If the polyurethane product is low quality or used, there is a high chance of it getting mixed with some other chemicals which cause roughness afterward.
- Not sanded properly
If the polyurethane is water-based and you’ve not sanded properly with fine-grit sandpaper after each coat, the roughening of the surface can occur over time.
How to Fix Surface Roughness of Polyurethane Finish?
- Abrade and screen the finish well to get the gloss shiny look back
- Clean the surface properly with a cloth after each coat of polyurethane finish to avoid getting dust, moisture, and water between the coatings.
- After every coating has dried completely, you can sand with fine-grit sandpaper without damaging the surface.
If none of these methods solve the problem, you have one option: sand the surface and apply the polyurethane finish again from the beginning. You can learn from your mistakes.
(*15*)7. Orange Peel Effect
The orange peel effect of polyurethane finish can occur because of using a roller instead of using brush or spray. The orange peel effect can occur if the roller isn’t properly napped after applying polyurethane.
Also, due to very low-temperature levels, the orange peel effect can occur in a polyurethane finish.
How to Fix the Orange Peel Effect of Polyurethane Finish?
For orange-colored polyurethane finish skin, you have only one option: sand everything and start over with spray or brush.
I don’t recommend using a roller when applying a polyurethane finish, without enough experience.
Also, make sure to keep the temperature level average (not extreme) while applying polyurethane coats and when they’re drying. Extreme weather conditions could alter the chemical composition of the finisher, and cause damage to furniture and woodwork.
(*15*)8. Streaking Polyurethane Finish
Streaking means brush marks. These streaking marks occur because the polyurethane finish dries faster than marks. This creates rapid gloss levels throughout the surface. It is possible to notice that some areas have high gloss and others not.
This is common when you use a water-based polyurethane. Streaking happens when,
- Excess free movement of the brush
- Not properly mixed the finisher
- Not having a wet edge
- No uniform spreading
I just finished putting on the second, and regardless of how it turns out, final coat of polyurethane on my desk. For some reason something I used on the desk is causing it to almost but not quite reject the polyurethane and it’s causing it to streak. I might have to sand.
How to Fix Streaking of Polyurethane Finish?
Screen the surface, then recoat with a new layer of polyurethane. Each layer must be sanded with fine-grit sandpaper (220-grit).
Also, if you’re good at finishing woods, put another coat of polyurethane where you can see low gloss levels and fill brush streaks carefully. Wait until the polyurethane is dry completely, then sand lightly to reapply it.
(*15*)9. Alligator Skin Polyurethane Finish
Yes, you read that correctly, if you do some mistakes your polyurethane finish will finally end up like an alligator skin with cracks and interconnected parts and ugly texture. This is called “crazing”.
Here’re the reasons that can cause alligator skin in polyurethane finish,
- High moisture content
If the moisture content in wood is too high when applying a coating, once the polyurethane coating dries, the water will trap inside and can cause the alligator skin texture.
- Alligator skin can occur under cold weather conditions
- If you’ve not removed the previously applied polyurethane coat layer completely, when you apply the new coat on top of that, the interconnected cracks can happen as crazing.
- If the coats are too thick
- If the product is expired or of low quality
Crazing caulk. It’s time to replace. #sealant #polyurethane thegoneapp.com/bUtFtFPM0M
So, let’s discuss how we can stop polyurethane finish getting alligator skin.
How to Fix Alligator Skin Polyurethane Finish?
Screen the surface, then recoat with a new layer of polyurethane. Before applying any layer of polyurethane, sanding is necessary.
(*15*)10. Cratering Polyurethane Finish
Crates happen when the polyurethane finish or the surface gets contaminated by dust, chemicals, or other effects. Cratering of the polyurethane finishes is caused by silicon, which can be found in sand or dust.
How to Fix Cratering of Polyurethane Finish?
To You can fix cratering polyurethane finishes by lightly sanding the surface. Next, wipe the surface with a dry cloth. Finally, apply a thin coat of polyurethane. Once it is completely dried, you won’t notice any craters on the surface.
(*15*)11. Cloudy Polyurethane Finish
Cloudy polyurethane finish happens because of several reasons. Such as,
- Using an old polyurethane finisher
- Extreme weather conditions
- Humid conditions
- Not stirring before application
Note to self – throw out the questionable polyurethane. The first coat of old, cloudy poly was used in the first pic. The second pic was coated with new can-wipe on poly. #neverstoplearning thegoneapp.com/ohe878zyLw
How to Fix Cloudy of Polyurethane Finish?
These steps can be used to remove a cloudy polyurethane coating.
- Make sure your polyurethane coating is dry.
- Remove flames or any other hating of cooling sources nearby
- Get a clean cloth and add some mineral spirit to it and wipe the surface to remove any dust and debris.
- Continue the wiping process until all blotching has disappeared. Let the surface dry.
- The surface can be sanded with fine-grit (220grit) sandpaper until it is clear.
- After cleaning the surface, apply three thin coats polyurethane finish to it. Let each coat dry completely before applying your next coat.
(*15*)12. Scratches In Polyurethane Finish
Any wood surface that applied a polyurethane finish can form scratches over time because of wear and tear. Scratches can occur with heavy use. Scratches can even occur when polyurethane finishes are applied.
Finally, done with the table! It was second-hand. My husband replaced the legs with locally sourced wood. I then restained it and smoothed any scratches. The legs were painted white with barn paint. Spent a lot of time making sure the polyurethane top coat was super smooth thegoneapp.com/7uhFtkf4AL
How to Fix Scratches of Polyurethane Finish?
Any scratches on the polyurethane finish can be fixed by sanding and starting over. Below are the steps to achieve a smooth polyurethane finish.
1. Identify the scratches
First, you need to examine whether the scratch is too deep or not. If the scratch is too deep, you will need to do more sanding.
2. Sanding
Sand the whole surface with a fine-grit sandpaper. Don’t sand too hard because it can damage the surface easily.
3. Cleaning
Wipe the surface using a clean cloth to remove clouds of dust and debris. A dirty surface can cause a lot of problems.
4. Application
Get a soft brush and apply polyurethane finish smoothly with uniform thickness all over the surface. Apply thin coats. Before applying the second coat, wait until the first coat is completely dry. If needed, rub sand between each coat.
@alliek0630 Sandpaper – to get out scratches – then finer & finer grades, then polyurethane with foam brush. thegoneapp.com/OJSnLL4Njc
(*15*)13. Blushing in Polyurethane Finish
There is a light milky color that can be seen in some polyurethane wood finishes and happen with lacquers as well. This is because moisture and water get trapped within the finisher. This is due to not properly sanding the surface before applying the finisher. With humidity changes, moisture in wood can penetrate the finish layers/coats.
Blushing can mainly happen due to the following reasons,
- Incompatible stain – Like applying water-based polyurethane over an oil-based stain
- High humidity
- Placing wet objects or water droplets in the same area for a long period of time
So, let’s discuss how can we fix blushing in a polyurethane finish.
How to Fix Blushes of Polyurethane Finish?
- After you have dipped the damp cloth in alcohol, gently rub the blushed areas with a damp tissue. This should be done gently and without using too much force. Let the alcohol evaporate from the blushed surface and dry it.
- Second, wipe the surface with the same cloth. Repeat this process until all blushes are gone.
- To remove any excess blushing, sand with 180 grit. Do this smoothly until you notice the dull look of the wood
- Finally, apply a thin coat of new polyurethane finish and let it completely dry. Then apply the second coat.
Read: How To Sharpen a Gouge – Top 2 Methods!
(*15*)14. Polyurethane Runs
Runs can happen when drying the polyurethane finish. This is one of the most common problems in woodworking. Because polyurethane finishes are slow drying, runs are quite common.
When drying both oil-based and water-based polyurethane finishes, you can see the run signs. You can cause runs by applying too much polyurethane, or by spreading too thick.
So, let’s talk about how we can fix polyurethane runs effectively.
How to Fix Polyurethane Runs?
- You can check the surface by using reflected light to brush it. While moving your head and wood, you’ll be able to notice if any runs there in a polyurethane finish.
- You can remove excess polyurethane finish with the brush or drag it to areas where you want less.
- After the finish has dried, identify any runs and wait until they harden before lightly sanding the area until the runs disappear. You can then reapply the polyurethane if you feel fine.
(*15*)15. Trapping Insects and Dust in Polyurethane Finish
This is the biggest headache that I suffered when working with a finisher. Sometimes bugs can land on the surface after I have cleaned it and applied finisher. I do clean the surface again.
Some people will ignore the bugs and put polyurethane coatings on top. But eventually, that small mistake will cost you more than you imagine. It is important to maintain a clean surface and not touch any debris, insects, or dust.
@venadavenu do you know if these are some kind of insect’s eggs?….wood has polyurethane coat, so I assume it can’t be fungi thegoneapp.com/CKen7EmqHX
How to Fix Polyurethane Finish After Trapped Insects, dust?
You can easily remove an insect that has landed on the polyurethane coating while it is still wet by using a toothpick and a needle. Normally, wet finishes will recover after the insect has been removed. You can apply a very small amount of finisher to any area where the insect has landed.
If an insect has landed on the surface while it is drying, I don’t recommend using a toothpick. It is important to wait for the surface to dry completely before you attempt to remove it. After the surface is completely dry, you can remove the insect by using light dry sanding (400 grit).
Never go for wet sanding because the finish can be mimicked by the lubricant, and you won’t notice the cutting.
Light dry sanding done, apply a thin layer more polyurethane coating and let dry completely.
Yay I’m done! The last coat of polyurethane has dried. Desk knobs tomorrow….💪💪💪 thegoneapp.com/N5Oe35mr2i
So, those are the 15 proven methods to fix polyurethane mistakes. Let’s have a look at the summary with all the mistakes and the most possible solution for each of them.
(*15*)Summary: How to Fix Polyurethane Mistakes?
(*15*)Did I cover all you wanted to know about: How to Fix Polyurethane Mistakes?
We will be discussing common mistakes made in polyurethane manufacturing and how to avoid them.
We reviewed all of the techniques and methods you can use to avoid any problems when using a polyurethane finish.
FAQ:
Q: What is polyurethane finish?
A: Polyurethane is a protective coating that forms a solid layer of plastic when applied on a wood surface.
Q: How to apply polyurethane finish on wood?
A: The general steps are: clean the workspace, ventilate the room, sand the wood, remove the dust, apply a thin coat of polyurethane with a brush or a cloth, let it dry, sand lightly, and repeat until the desired number of coats is achieved.
Q: What are the benefits of using polyurethane finish?
A: Polyurethane finish enhances the natural beauty of wood and protects it from wear and tear, scratches, spills, abrasion, and temperature variations.
Q: What are the drawbacks of using polyurethane finish?
A: Polyurethane finish can be difficult to apply evenly, especially on curved or intricate surfaces. It can also emit strong fumes that require proper ventilation and safety precautions.
As I have mentioned, most of the mistakes you can simply avoid by sanding with fine-grit sandpaper and reapply the polyurethane finish using proper guidelines, and giving enough time to dry completely.
I hope this article helped you to understand how to correct polyurethane errors in your next woodworking project. So, let’s give it a try!
