Before you can re-coat, clean, and use your linseed oil finish, the wood oil needs to dry. So how long does linseed oil take to dry?
Boiled linseed oil takes 24 hours to dry between coats and 3 days to fully dry (cure). Boiled linseed oil contains drying agents and petroleum-based solvents that make the wood dry faster. On the other hand, Raw linseed oil takes 3 days to dry between coats and 2-6 weeks to cure.
To get a faster dry time, you must apply the wood oil only at room temperature above 60 degrees (F). Also, you must wipe off the excess wood oil after the application. That’s because the temperature, humidity levels, and thickness of the coat affect its drying time.
Linseed Oil Drying Time Between Coats
Boiled linseed oil must dry for 24 hours between coats, while raw linseed oil must dry for 72 hours between coats. The oil thinners and drying agents in the boiled linseed oil make it dry faster.
You must allow double the usual time in cold or moist conditions because the wood oil takes longer to dry in humid conditions. That’s because linseed oil dries through evaporation, and the evaporation rate is slower during humid conditions.
If you re-coat too soon, the finish will turn sticky. That’s because the new coat will prevent (stop) the evaporation process of the old coat. This means the old coat will still be wet, and the new coat won’t stick over a wet coating. All of this leads to the finish turning sticky and eventually peeling off.
Factors That Influence Linseed Oil Drying Time:
Here are five factors that determine the dry time:
1. The Number of Coats
The more coats you apply, the longer the finish will take to dry. That’s because there will be more oils in the finish, meaning the evaporation will take longer. Conversely, if you apply fewer coats, fewer oils will be in the finish, so the evaporation rate will occur faster.
The thickness of the coat is also important. The thicker the coat, the longer it takes to dry. So, you must thin the linseed oil coating before applying it to get a faster dry time.
2. Linseed Oil Type
There are different linseed oil types, each with a different drying time. For instance, boiled linseed oil dries faster than raw linseed oil. The brand of the linseed oil determines the drying time too. Some brands add more drying agents or use a thinner version for faster drying time.
3. Humidity Levels
The room temperature determines the drying time. For instance, the finish dries faster if the weather is dry and warm. But, if the temperature is moist and cold, the finish dries slower.
The humidity levels also affect the dry time. Humidity measures the level of moisture or water in the atmosphere. If the humidity exceeds 60%, the finish takes longer to dry. That’s because there’s more water in the atmosphere.
The humidity and temperature also determine the speed of the evaporation process. The faster the oils in the linseed oil evaporate, the faster the coating becomes dry and rigid. So increasing the evaporation rate also speeds up the dry time.
4. The Applicator Method
The application method determines how fast the finish dries. For example, the finish will dry faster if you use a paintbrush to apply linseed oil. That’s because a paintbrush will apply thinner coats. On the other hand, a rag will apply thicker coats, so the finish will take longer to dry.
5. Did You Wipe The Excess?
After applying linseed oil, you must wipe off the excess wood oil within 20 minutes. If you don’t, the coat will be thicker and take longer to dry.
How to Make Linseed Oil Dry Faster?
There are 2 ways to make it dry faster:
- The pre-application method
- The post-application method
This guide will show you how both methods work and how you can use them:
1. The Pre-Application Method
The pre-application method involves steps that you can take to modify the wood oil before its application.
To make linseed oil dry faster, you must thin it before applying it. To thin linseed oil, use mineral spirits, turpentine, or white spirits. All of these are petroleum-based and compatible with linseed oil.
For this method, you’ll need these tools and supplies:
- Mineral spirits or turpentine
- A paint mixer or stirring stick
- A clean paint bucket
- A pair of gloves
- A measuring cup (optional)
Here is a guide for this method:
- Pour the linseed oil into a clean paint bucket.
- To thin it, use a ratio of 2:1 (2 parts linseed oil, 1 part paint thinner).
- Pour the paint thinner (mineral spirits or turpentine) into the bucket.
- Stir the mixture for a few minutes or until the flow is even. There shouldn’t be any clumps in the wood oil.
- Let the wood oil settle and test it before applying it over the rest of the surface.
Tip: Always put the safety goggles on when working with thinners and solvents.
2. The Post-Application Method
The post-application method includes steps you can take after applying the wood oil. This include:
- Opening all windows and doors, so there is better airflow.
- Use a hairdryer to speed up the drying time.
- Reduce room humidity with a dehumidifier.
- Turn on the fans in the room, so there is better air circulation around the coating.
- Use paint tents to prevent dust and mildew from settling on the wet coating.
- Wipe off the excess linseed oil a few minutes after its application.
Here are 10 other tips to follow when applying it so it dries faster:
- Apply the wood oil only when the temperature and humidity are favorable.
- Don’t apply too many coats of linseed oil.
- Always wipe off the excess after application.
- Never apply it on a wet surface.
- Choose boiled linseed oil over raw linseed oil.
- Thin it with mineral spirits before application.
- Provide proper ventilation in the room.
- Don’t use or clean the finish before it has cured – the solvent or cleaner can dissolve the linseed oil, making it wet again.
- Scuff between coats with fine-grit sandpaper so the next coat can adhere and dry properly.
- Always wipe and clean the surface before applying it. If the surface is dusty, the dust nibs will not allow the oil to stick, making the linseed oil dry slower than usual.
Different Types of Linseed Oil And Their Drying Time:
Refined Linseed Oil
Refined linseed oil takes between 12 and 24 hours to dry enough for re-coat, but the entire finish takes 3-5 days to cure. Refined linseed oil dries fast because it is lighter and reinforced with additives that reduce its dry time.
Refined linseed oil is linseed oil that has gone through mechanical pressing and chemical additives, and has been mixed with solvents. This type of woodoil is lighter than others which explains why it dries fast.
Double-Boiled Linseed Oil
It takes double-boiled linseed oil 12 hours to dry for a re-coat and 24 hours to cure. This wood oil has been heated twice and mixed with more drying agents and solvents. Since there is a higher level of drying agents in the wood oil, it dries faster.
Polymerized Linseed Oil
It takes polymerized linseed oil 24 hours to dry for a re-coat and up to 5 days to fully cure.
There are different types of linseed oils, and they each have a distinct dry time. Check the manufacturer’s instructions to know how long the wood oil will take to dry.
But on average, boiled linseed oil coats take 24 hours to dry and 3 days to cure, while raw linseed oil takes 3 days to dry enough for a re-coat and 3-6 weeks to cure.
To speed up its drying time, increase the evaporation rate by increasing the airflow and reducing the humidity levels around the coating.
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,