Although lacquer is known for its beautiful, clear, and glossy finish, it sometimes turns white, cloudy, and dull. The good thing is that the problem is usually easy to fix if you know what has caused the blushing in lacquer in the first place.
The most common cause of a milky lacquer finish is moisture in the air. When sprayed on the surface, the lacquer typically causes a cooling effect as it dries. And if it cools down the surface below the dew point, you get condensation. This water droplet will eventually evaporate, leaving behind a white, cloudy finish.
To fix the discoloration in your lacquer finish, you can start evaporating the moisture into the air using a heat gun. If that doesn’t help, you must use a lacquer thinner to eliminate white spots. Lacquer retarders can also help by slowing the drying time, but they should be used cautiously.
In this blog, I will tell what exactly is a white lacquer finish, a few more causes of the lacquer finish turning white, and how you can fix this cloudy substance. So, if you are having trouble with your lacquer finish, read on to learn more about the issue before trying to fix it.
Causes of Cloudy Spots in Lacquer?
Lacquer is an excellent choice for those seeking the fastest drying finishes available – it can cure within 24 to 48 hours or sometimes less. That’s why it’s an ideal choice for those who desire an instant transformation without having to sand or wipe surfaces down before applying the coat.
The only drawback is when it’s drying over wood surfaces like doors, furniture, and cabinetry; it can sometimes leave a milky layer due to the immediate cooling effect that makes it dry fast.
There are several reasons for this, but the most common is moisture in the air (relative humidity above 60%) which stays underneath the lacquer layer in the form of microscopic water bubbles. Once the drying happens and the lacquer gets hardened, there will be white spots and blushing all over – which can be challenging to remove.
When the light hits these water bubbles on your lacquer finish, they become more visible and can cause a dull white mark on the wood surface, compromising its beauty.
Aside from moisture, a few additional causes of blushing in the lacquer can be:
a) Over-spraying – Applying too much lacquer in one go can lead to blushing problems. You should, therefore, always follow the manufacturer’s recommendations on how much you can apply based on the substrate and application methods.
b) Contaminants – If there are any contaminants on the surface before you start spraying lacquer, they can cause problems. To get the right finish without any problems surface must be clean and free of dust, oil, or debris.
c) Improper ventilation – If the area where you are spraying is not correctly ventilated, the air’s moisture will not escape easily, causing the lacquer to turn white.
d) Too much lacquer thinner – Lacquer thinner is an essential part of the process because it helps the lacquer evaporate and become dry. But, if you use it in excess, it will not be able to dry correctly and will be prone to blushing.
e) Incorrect dilution ratio – If you don’t mix the lacquer properly, it can also lead to blushing. Removing and fixing the spray lacquer finish problems is essential not only because of the beauty of the furniture but also to maintain its value.
Plus, if you do not fix the blushing in lacquer soon, the moisture that remains beneath can cause the wood to swell, distort, and rot sooner or later. So, it would be best never to ignore the blushing and milky spots on your furniture – fix them as soon as you notice them.
Fixing a Blush and Cloudiness in Lacquer Finish
Removing white spots from your lacquer finish is relatively easy if you take action immediately. The first step, however, is to identify the cause of discoloration. If it is due to moisture, you can try one of the following solutions:
1- Evaporating the Moisture
The trapped moisture inside the lacquer can be easily removed using a hairdryer and iron at home. Let’s see how…
- Start by placing a soft cotton cloth on the surface with white spots of lacquer finish.
- Switch on the iron and set it to the medium setting
- Place it on the cloth and move it in a sweeping motion
- After a few minutes, check the spots by removing the cloth; they might be vanishing and fading with heat
- If there are still spots that need to be removed, put the fabric again and try ironing for a few minutes
- Remove the cloth and now take your hair dryer (set at the lowest setting)
- Apply the heat from the hair dryer – by holding it close to the surface at a distance of about 3 -4 inches
- You will notice all the white spots vanishing away with the heat slowly
Continue the above process until the white spots have gone from an entire area. Do not miss any spots; treating them later (once you are done) will be difficult.
This entire process, when carefully done, should eventually help you get rid of all the cloudiness in just a few minutes. You only need to ensure not to use the steam mode on your iron, as it will only worsen things. Also, do not apply excessive iron heat directly on the wood surface, as it can damage the entire finish layer.
2- Thinning Lacquer Finish
Another way to remove the moisture and white spots from the finish is by using lacquer thinner. For this method, you will need to:
- Start by pouring some lacquer thinner into a bowl
- Soak a clean cotton cloth in the liquid and wring it to remove the excess
- Now apply this cloth to the surface with white spots
- You will see the cloudiness and moisture being transferred from the finish to the cloth
- Continue the process until you have removed most of the moisture from the surface
- Once you are done, take a clean, dry cloth and wipe away any thinner from the surface
Remember that this method will work effectively only when the trapped moisture isn’t too deep. The thinner will cut the lacquer finish to make the pathway for excess moisture to evaporate. Once the moisture particles come out, the lacquer finish does not appear white.
That said, if the moisture has penetrated too deep, the process won’t work well – it is better to lightly sand the surface and start over with a new finish.
3- Adding a Lacquer Retarder
Using Lacquer Retarder (also known as blush remover) is one of the most effective techniques to eliminate the cloudy spots on your furniture. Expert woodworkers generally use this to fix the lacquer blushing in highly humid conditions.
A lacquer Retarder will work by slowing down the lacquer’s drying time, giving it more time to evaporate any trapped moisture beneath the surface.
Typically, you will need to add 2-3% of the lacquer retarder to the total lacquer volume before applying the finish to the surface. Depending on the humidity conditions, you can go as high as 5% to 10%. This mixture will then prevent the lacquer from turning white as it dries.
You can find Lacquer Retarder in any convenient hardware store or online retailer. However, when using them, always follow the instructions on the packaging carefully.
4- Use Dehumidifier or Silica Gel
If you’re living in a humid area or if your furniture resides in an overly moist setting, it’s hard to eliminate the moisture spots. The easy fix, however, is to reduce the humidity levels of that room with either a dehumidifier or desiccant silica gel packets.
After spraying the finish, place the dehumidifier in the room where your furniture is placed and turn it on. Keep the device running until the humidity level has dropped to around 45% to 50%.
You can also use some silica gel packets to reduce the moisture in the air if you do not have a dehumidifying machine at home. Place them near your furniture and allow them to slowly absorb the moisture from the air, eventually helping to remove the cloudy spots on your furniture.
The dehumidifier or silica gel packets can also be used while applying the finish to your furniture. This will help prevent the water from condensing under the lacquer finish, keeping it from blushing while it dries.
How to Apply the Lacquer Finish Correctly to Prevent White Spots?
The key to avoiding cloudy spots in the first place is to apply the lacquer finish in the right conditions. This means ensuring the humidity level is below 50% and the temperature above 70 degrees Fahrenheit.
It is also recommended to apply the lacquer finish in a dust-free environment because even the smallest dust particles can cause imperfections, resulting in a cloudy appearance.
Follow these steps to avoid cloudiness and correctly apply the lacquer finish to your wood surface.
Step 1- Prepare your working area
This should be done by setting up a dust-free environment. You should primarily start by using a HEPA filter vacuum to remove dust particles from the air. Then place a dehumidifier nearby or take your project to an open and well-ventilated space outside.
Step 2- Clean and sand the wood surface
Next, using a tack cloth, wipe down your furniture’s surface, and remove any lingering dust particles on it.
If you are working on a previously lacquered wood surface (after fixing the white spots), wipe the entire surface with a piece of rag dampened in denatured alcohol or mineral spirits. This will help clean the old lacquer finish and give the new coat a smooth surface to adhere to.
After that, allow the surface to dry for a few hours; then, sand the surface lightly using fine-grit sandpaper (220). Unfinished wood coated with a fresh lacquer finish should be sanded nicely with 180-grit sandpaper to create a smooth surface.
Make sure you sand the surface evenly by applying even pressure along the direction of the wood grains. This will eliminate the chances of getting any marks or visible scratches on the surface when you apply the finish. After sanding, use a tack cloth or a lint-free rag to remove the sanded dust particles from the wood surface.
Step 3- Prepare your lacquer finish
Pour a gallon of lacquer finish and 6-8 ounces of lacquer retarder into a container. Stir the mixture slowly and thoroughly using a stir stick until the ingredients are completely mixed.
It depends on the dryness of the wood and environmental conditions; you can increase the lacquer retarder quantity. But, I would recommend the retarder to be not more than 10% of the total lacquer finish.
The correct quantity of lacquer retarder will help to prevent the lacquer from drying too quickly by giving the it enough time to level and flow evenly on the surface.
You can also use a lacquer thinner (or acetone) to adjust the consistency of the lacquer mixture if it is too thick. I recommend starting with 1/2 pint of lacquer thinner for a gallon of lacquer finish. However, be very careful when adding the thinner as it can quickly thin out the lacquer mixture, making it challenging to apply.
Step 4- Spray the lacquer and allow it to dry
When the solution is mixed and prepared – load it into your paint sprayer for spraying.
Start by wearing a facemask, adjust the air regulator to 30 PSI, and hold the nozzle of your paint sprayer about 12 inches away from the surface of the wood.
With a steady hand, spray the very thin layer evenly across the surface in a side-to-side motion. As you move the sprayer, overlap each stroke by 50% to ensure even coverage and prevent bare spots. After spraying the first lacquer coat on the entire surface, allow it to dry for 30 to 60 minutes.
TIP: If you are not very confident, practice lacquer spraying on a piece of cardboard or any other scrap wood before spraying the actual project.
Step 5- Sand and apply additional coats of lacquer
Once the first coat is completely dry, sand the surface lightly with very fine-grit sandpaper (320 or 400). Use a tack cloth or a lint-free rag to remove dust particles from the wood surface.
Now you are ready to apply the second, third, or even fourth coat of lacquer. Follow the same procedure as you did for the first coat and allow each coat to dry completely (30 to 60 minutes) before applying the next one.
Once you have applied the desired number of coats and allowed the final coat to dry completely, sand the surface one last time with ultra-fine sandpaper (600). Then using your tack cloth remove any dust particles produced on the wood surface.
You should now have a nice, smooth, shiny surface without any cloudy lacquer finish.
Tips and Warnings
Though the cloudy lacquer finish is not a big problem, it can be very frustrating, especially if you have put in so much effort to achieve a perfectly smooth surface.
So, to keep such problems at bay, here are a few additional tips and warnings that you should need to keep in mind during the application process:
- Allow at least 24 hours to cure the sealed lacquered surface before using it.
- Do not sand the surface too aggressively at any stage, as it can damage the wood and its beautiful grain patterns.
- If possible, use lacquer thinner, lacquer finish, and retarder from the same manufacturer. This will avoid the incompatibilities that can lead to a cloudy finish.
Brands like Sunnyside, General Finishes, Minwax, and Zinsser make good quality lacquer products. You can check and compare them online before purchasing one.
The Bottom Line
A cloudy lacquer finish is a common problem when applying a lacquer finish- but it’s relatively easy to fix. The important thing is to take your time and be patient. Make sure you follow all the steps carefully and do not rush the process. Once you have fixed the blushing, you can apply a fresh coat of lacquer if needed.
Applying a lacquer finish is also not difficult, but it does require some time and effort. If you do it carefully, your project should last for decades (or even more) without any problems.
Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls.
He had worked as a painter for over a decade serving customers in areas such as Charleston, Mount Pleasant, Beaufort, and Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques implemented in his profession. You may read more about him here or get in touch with him here.