It is not uncommon to have a cloudy or milky hue on wood after finishing, and one may wonder how to fix it. This problem mainly occurs due to the humidity or moisture present in the air during “finishing.” The term “finish” refers to a clear, transparent coating that’s applied to wood as a liquid by brushing, spraying, or wiping it on with a piece of cloth. In essence, finishing serves two purposes: protection and decoration.
Your wood may have a cloudy color (blushing) because the wood finish was applied in a humid condition. As a result of this, moisture enters the finish and gets trapped. If it does not get a chance to evaporate before the finish hardens, it turns cloudy. To fix wood looking cloudy after a finish, add a retarder to your finish. A retarder is added to the coating mix to slow down the drying time, hence more time for the trapped moisture to evaporate.
Apart from humidity, several factors may be responsible for blushing. In this article, we will be exploring the other factors that contribute to cloudiness in wood and how to prevent their formation.
Why Does My Finished Wood Look Cloudy
There are various reasons why blushing may occur in wood after applying the finish. Some of which are:
- Applying Too Thick Finish.
Overly thick applications of clear coating complicate the evaporation process, resulting in longer process times and blushing. Therefore, an average coating thickness is recommended for application. A single coating application or a maximum of two coats followed by proper drying and sanding will be safer and produce a better surface finish than many layers applied wet at the same time.
- Working in High Humidity.
It is common for wood finishes to build up moisture when applied on a humid or cold day. When the finish hardens, water will remain trapped inside since it will not completely evaporate. Due to this, cloudiness or milky residue often appears on the finished wood.
- Not stirring enough before using.
Water- and oil-based polyurethanes are varnishes that dry to a glossy finish. Typically, manufacturers add flattening agents like zinc oxide to create matte finishes. These agents disperse reflected light and knock out a sheen. Consequently, the material gathers at the bottom of the container, which is why it’s important to stir it before using it thoroughly. If it is not adequately mixed, it is likely to blush.
- Applying the finish too quickly.
When the finish is applied too quickly on the wood, it would also definitely result in blushing. It is best if you took care in using a given amount within a particular time frame.
- By using an old product that has been stored in extreme cold or heat.
Storage conditions have a significant impact on a finishing’s output. You should put into consideration the age of the finish since you will likely run into more problems if you use an old can.
How To Fix Cloudy Color After Finishing Wood In Five Steps
When you observe blushing, i.e a cloudiness on your wood after applying a finish, do not panic. It happens sometimes. To get rid of blushing, the following can be done.
Step One: Reduce the humidity of the room
Blushing is primarily caused by high humidity. An air dehumidifier can reduce the moisture in the room to 50% or less. Therefore, it is favorable to work in an environment where humidity levels are low.
Step Two: Wipe the wood with denatured alcohol
Lightly wipe the blushed area with a cloth dipped in denatured alcohol. Make sure not to rub vigorously; wipe gently with light strokes. In addition to using denatured alcohol to eliminate wood cloudiness, steel wool is also helpful for getting rid of the problem.
Step Three: Wipe again
You may apply a light coat of alcohol again if the blushing persists after the first application.
Step Four: Clean off wax and dirt
Any wax or polish that alcohol could not fix with cloudiness should be cleaned with detergent and water, then sanded with an abrasive of 180-grit or one with a more refined texture. Sand off the gloss, but do not go too deep. Finishing the project should render it dull in appearance.
Step Five: Coat with fresh Lacquer
On the area you have sanded, apply one coat of Lacquer. A fresh coat of Lacquer softens a surface, meaning water can evaporate, and the blushing will disappear. It is sometimes necessary to add a retarder to the Lacquer to slow the drying and allow moisture to escape more easily.
In polyurethane finishes, another coat won’t remove the cloudiness as it would in the case of Lacquer because, unlike Lacquer, polyurethane cures. A dry finish won’t re-emulsify, and adding more finish will only worsen the cloudiness.
Cloudiness in polyurethane can be removed by covering the affected areas with mayonnaise or petroleum jelly. You should wash the wood the next day after it has soaked overnight. There may be an improvement since the oil in mayonnaise or petroleum jelly wicks moisture out of the finish. Attempt the process again if you noticed a difference, but the cloudy effect has not entirely disappeared.
Pro-Tips For a Precise Finish
Below are a few tips to bear in mind so you can achieve a finish without it going cloudy.
Keep The Right Temperature When Working: Cold temperatures and high humidity can seriously disrupt the finishing process, thus increasing the likelihood of blushing. Therefore, it is recommended that you install an oven in your finishing room to prevent these problems. Independently of the environmental condition, the Oven can control the temperature and humidity in the finishing room.
Do Not Apply an Old Finish: If you have to break or peel off a layer of dried finish from inside the can, then it has outlived its usefulness. The reaction does not stop as soon as the drying agents start reacting with the oxygen trapped within the can. The old finish you apply may never completely dry if this occurs. The best option is to buy only as much finish as you need for each project. Always begin each project with fresh products.
Use Lacquer Retarder: A retarder is a solvent that is used to slow the drying process. Most often, it’s combined with the topcoat. The addition of retarder will take much longer for the coat to dry overall, increasing the time available for the water vapor to exit the coating layer and escape. The addition of a retarder can solve the blushing problem in many cases.
Nevertheless, you should ensure that the addition retarder is not excessive. Using too much retarder will cause the drying process to become slower, affecting the entire production process. Additionally, retarders can affect the gloss of the coating films produced.
Do Not Apply Too Much Clear Coating: Applying a clear coating that is too thick will make the evaporation process more complex and more prolonged, allowing blushing to occur more quickly. Therefore, an average coating thickness is appropriate for coating application. Using one clear coat or two at most after sufficient drying and sanding is safer and will produce a better finish than applying a wet coat many times at once.
Use A Good Quality Thinner: As part of reducing viscosity, a thinner is added to a finishing material to dissolve the material. However, for a thinner to work correctly, there must be enough solvent in it (the material that dissolves the clear coating). Therefore, it is best to choose a thinner that contains enough solvent to diminish the chances of having problems in the finishing process.
Thinners with too much diluent will impact evaporation in the finishing process. However, a suitable thinner can efficiently resolve other finishing problems.
How TO Fix Cloudy Lacquer
Lacquer is an evaporative finish; it cures with the evaporation of its solvent. Lacquer skims over, i.e., it dries from the surface inward. However, blushing, i.e., cloudiness or milkiness, is typical with lacquer finishing.
To eliminate cloudiness on finished wood, follow the procedure.
- Reduce the humidity in the room by using a dehumidifier or opening the windows and doors to increase airflow and reduce moisture trapped inside the area to be sprayed. In most cases, you would like to achieve the lowest relative humidity possible, but most manufacturers suggest a 50% or less relative humidity level.
- The next step is to mix up a batch of 50/50 lacquer retarder and lacquer thinner to be applied in one coat. The lacquer retarder lengthens the dry time, so any moisture trapped can evaporate. In addition, it dissolves the previous lacquer coat so that the cloudy appearance disappears.
- Fill a spray rig with the mixture and apply a smooth fog coat using the lowest pressure and volume. Aim to minimize the level of overspray and bounceback.
Note: Be sure to wear a respirator mask before spraying as this combination can be hazardous.
- Once the finish has dried, hand sand lightly with 320 grit sandpaper, use a clean rag to dust off the area after sanding, and feel its smoothness with your hand.
- Following this, you can spray on the second coat of lacquer and lacquer thinner. Again, the present humidity may determine whether a lacquer retarder is needed.
You can sand after spraying and repeat this process as many times as you want.
Having looked through the cause of cloudiness in wood, how to avoid it, and how to remedy the situation, you should be ready and confident to carry out your next project. A perfectly clear finish is attainable if the necessary guides and tips are followed. Follow all these and you should never struggle with cloudy finish ever again.