Also known as Flaxseed oil, Linseed oil is a popular wood finish used all over the world. It can be very effective against scratches and mild weather conditions.
Linseed oil does not fully waterproof wood, however it does improve wood’s water resistance. This means that wood coated with linseed oil can still be damaged by water.
Read on for information about waterproofing wood with linseed oil with a step-by-step guide to do it properly, as well as the pros and cons of using linseed oil to waterproof wood.
How Waterproof Is Linseed Oil?
Linseed oil is inherently hydrophobic or water-repellant. However, it’s not super water-resistant when applied as a wood finish. In fact, wood protected with linseed oil can still be prone to water damage.
Therefore, you shouldn’t get wood coated with linseed oil in direct contact with cold glass because it can easily develop water rings.
If the wood gets wet, try to dry it out as soon as you can to prevent stains.
Should I Use Raw Or Boiled Linseed Oil?
To choose which linseed oil to use, you need to understand the differences between the different types. For starters, there are three types of linseed oil to choose from: raw, boiled, and polymerized.
Here’s an outline of the most basic differences between the three types:
Raw Linseed Oil
That’s the purest form of linseed oil. However, it isn’t always practical. Actually, we don’t recommend it as a furniture finish as it requires a relatively long time to dry.
In fact, it can take up to several weeks for each layer. However, if applied as a thin coat and given ample time to cure, raw linseed oil makes a safe and ideal finish.
Boiled Linseed Oil
On the other hand, boiled linseed oil is a common wood finish as it doesn’t require as much time to dry. It contains some toxic substances that are released during the curing time.
That’s why it’s not the best choice when dealing with surfaces that may get in contact with food such as dining tables and cutting boards.
Interestingly, boiled linseed oil (BLO) isn’t actually boiled or even heated. In fact, the difference between this type and raw linseed oil is the addition of drying agents to facilitate using it as a finish for wooden furniture.
Polymerized Linseed Oil
This type combines the best of both worlds. On the one hand, it’s pure and doesn’t pose any health threats, and on the other, it dries fast. This makes it a favorite among craftsmen.
Polymerized linseed oil is made by heating raw linseed oil for several days to around 572°F in the absence of oxygen. This process causes the occurrence of a polymerization reaction, thus the name.
This increases the viscosity and decreases the drying time of the oil.
How To Waterproof Wood Using Linseed Oil?
Here’s a simple step-by-step guide to applying linseed oil to wood:
1. Clear The Surface
Before you apply linseed oil, you should make sure that your surface is smooth and clear. Use 120-grit sanding paper to sand the surface of bare wood.
This ensures thorough penetration, thus stronger coating. This way, linseed oil offers more protection.
2. Create A Mixture
This step is optional, but most craftsmen opt for it to ensure better penetration. You can mix linseed oil with several other substances.
For instance, some people mix the first coat with a mild solvent or odorless thinner. Others mix linseed oil with apple cider vinegar. Either way, it results in a sturdier layer of coating.
3. First Coat
Don’t apply the oil directly onto the wood. Rather, pour some oil on a piece of cloth and rub it on the surface in an outward direction. Use a brush, cloth, or roller to spread the first coat of oil onto the wood surface.
It’s important to be very accurate with this step. Always apply more oil instead of rubbing too hard. You should also make sure not to touch the oil while the wood is still absorbing it and not to leave any puddles of oil behind.
4. Wipe Clean
Give the first layer of coating about 30 minutes to get absorbed by the wood.
After that, wipe the surface with a very thin piece of wool to remove any extra oil. This step is necessary in order not to end up with a sticky surface.
5. More Coating
Every about 24 hours, repeat the entire process to add two or three more layers of coating to the wood.
Typically, your waterproof wood would need between several days and several weeks to completely cure. You can tell that the wood is ready for use when you slide your finger smoothly across the surface.
Tips to Waterproof Wood With Linseed Oil
- Don’t apply linseed oil to painted, varnished, or waxed wood because this prevents the oil from penetrating the surface.
- Treat outdoor wood against fungi and insects before applying oil.
- Use 600 to 800 grit sandpaper or a 000000 fine steel wool to clear the surface at least 24 hours after applying the last coat.
Benefits Of Using Linseed Oil On Wood
Here’s a list of the advantages of using linseed oil to waterproof wood:
- Highlights the depth of texture and color of wood.
- Can be easily repaired if dented and scratched.
- Eco-friendly and non-toxic.
- Offers deep penetration and protection against mild weather and humidity.
- Can be mixed with other finishes for further protection, especially for outdoor wooden furniture.
Cons Of Using Linseed Oil On Wood
On the flip side, there are also some disadvantages of using linseed oil on wood, such as:
- May require occasional re-oiling.
- May develop water rings.
- Can be easily scratched.
- Discolors slightly over time.
- Leaks with severe changes in humidity or temperature.
- Can easily stain with colored liquids seeping into the wood.
So, does linseed oil waterproof wood? No, it doesn’t, yet it makes wood water-resistant.
We recommend that you use polymerized linseed oil since it doesn’t require as much time as raw linseed oil and isn’t as toxic as the boiled form.
Linseed oil offers great protection as it penetrates the wood grains thoroughly. However, it usually discolors over time, especially if applied outdoors.
Although waterproofing your wood with linseed oil can be time-consuming, the end result is totally worth it.