Linseed Oil for Wood Explained: A Comprehensive Guide

By MWB-Team •  Updated: 05/19/23 • 

Linseed oil is one of the most popular oil finishes used to coat and protect different wooden surfaces. It is a penetrating oil that penetrates deeper into the wood fibers to protect against various elements, such as humidity or scratching. In this post, we’ll discuss more about linseed oil wood finish.

Origin of Linseed Oil

Linseed oil is extracted from the seeds of the flax plant, and thus its other name, flaxseed oil. In its raw state, linseed oil is inefficient for protecting wood and takes longer (weeks or months) to cure. To improve it and make it better, metallic driers are added. These include salts of manganese, zinc, or cobalt.

Types of Linseed Oil

You’ll find three main types of linseed oil in the market. These are raw, boiled, and polymerized linseed oil. All these have their advantages and disadvantages.

Raw linseed oil is the purest form, or simply linseed oil in its natural state. It has no added additives and, when applied to wood, can take several weeks or months to dry. This makes raw linseed oil quite unpopular for use when finishing wood. However, applying it in thinner coats and giving it plenty of time to cure can make a good finish.

Boiled linseed oil, or BLO, is not boiled, and there’s no heat involved. The difference compared to raw linseed oil is that BLO has added driers that speed up the introduction of oxygen and thus help the finish cure faster. These driers can be petroleum-based or heavy metals like zinc, manganese, or cobalt. When boiled linseed oil is applied to wood, and the excess is wiped off, it can take about a day to cure.

Polymerized linseed oil is created by heating raw linseed oil in an oxygen-free environment at around 500 degrees Fahrenheit. This thickens the raw linseed oil, makes them cure faster when exposed to oxygen, and gives them a hard and glossy finish. Compared to boiled linseed oil, polymerized linseed oil contains no additives to improve its performance. Check out our in-depth guide on the different types of linseed oils.

Pros of Linseed Oil

Cons of Linseed Oil

Which Linseed Oil to Use?

To get the best benefits of linseed oil, I’d advise using polymerized or boiled linseed oil for wood. This is because, with these two types of linseed oil, you can build a thicker film, offering better protection. They are also more durable than raw linseed oil.

If you’re looking to add warmth to a piece of wood, linseed oil is great to use. Linseed oil yellows as time passes, which adds warmth. Raw linseed oil will yellow more compared to BLO and polymerized linseed oil.

How to Apply Linseed Oil to Wood

Like other oil finishes, linseed oil is very easy to apply. Below are some steps to follow during the application.

  1. First, sand down the piece of wood you’re finishing to at least 100 grit sandpaper.
  2. If the wood was previously refinished, strip it down and then continue to sand it down.
  3. Once done, wipe the oil with a rag and wipe off the excess.
  4. Once it is cured in a day or two, lightly sand it with 220-grit sandpaper and apply another coat.
  5. Repeat the process until you get the desired results.

Linseed vs. Danish vs. Tung Oil

Danish oil is a mixture of different oils, resins, and solvents. There is no one formula to make Danish oil, and the rations and components used differ between different manufacturers and brands. Compared to linseed oil, Danish oil dries faster, forms a hard-wearing and durable finish, and has better resistance to elements.

Tung oil is extracted from the nuts of the Tung tree, which is native to China. Compared to linseed oil, Tung oil is more expensive and is more water-resistant after about six coats. It also cures slowly but slightly faster than Tung oil. However, it is harder to apply and make it look good.

MWB-Team

Hello there! This is the Make Wood Better Team. Here, we share informative how-tos and guides focused on making wood better. Whether it's finishing wood, maintenance, or restoration, there's something on this website for you to learn and improve your skills.