How to Darken Linseed Oil? Best Methods That Really Work

There are a few articles online that guide you on how to darken linseed oil. Some of them are effective, and others are not. Today, we’ll be discussing how to darken linseed oil with the best methods that really work.

Many car owners use linseed oil to rustproof their cars economically. Linseed oil is also used to restore shine to faded car plastic parts. It’s used in woodworking projects and in many other spheres. Apart from being cheaper than other finishes, linseed oil is also organic. While the raw and boiled linseed oil darkens over time, there’s always the question of ‘how to darken linseed oil.’

If you’re about to commence on a project with linseed oil, you’re in the right place. Today, we’ll cover different methods to darken linseed oil and step-by-step instructions to achieve them.

What is Linseed Oil?

Linseed oil or flaxseed oil is derived from the flax plant. Natural oil has a variety of commercial uses, including; paint production, printing ink production, and wood preservation.

Unlike other finishes, boiled linseed oil penetrates the wood and protects more than the surface layer. Linseed oil is also used to make varnishes and stains.

With all its different uses and by-products, linseed oil is arguably one of the best natural oils. Apart from woodwork, linseed oil is also popular amongst car owners. Especially car owners who love carrying out DIY projects on their cars.

When used alone, linseed oil can darken over time. But there are different factors that can affect the darkening process.

Best Methods to Darken Linseed Oil

Linseed oil typically comes in a light yellow or golden color, but depending on the project, people can prefer them darkened. Sometimes, a project can call for pigmented linseed oil. You can quickly darken linseed oil with the methods below:

Add oil-based dry aniline paint

In this method, it is essential to understand the complexity of aniline paints and how they work. Adding dark pigmented oil-based aniline paint to linseed oil will darken the color. However, you have to use the correct application techniques to avoid the color looking streaky.

Add wood stain to linseed oil

As we said earlier, linseed oil is popular in woodworking, and manufacturers in the industry have been using wood stains to darken linseed oil for years. Are wood stains effective for metal surfaces?

Yes. Well, traditional liquid wood stains are too thin for metals. However, gel wood stains work well because they’re not made for just wood.

Over-the-counter gel wood stains like Minwax can be used to darken linseed oil. Other manufacturers like Old Masters also make gel wood stains that can be used to darken linseed oil.

Step-by-step Instructions for Darkening Linseed Oil

The two best methods for darkening linseed oil are adding oil-based dry aniline paint and adding wood stains.

These two methods sound simple enough, but you must follow accurate measurements and application techniques to avoid color separation.

Adding Oil-based Dry Aniline Paint to Linseed Oil

Using oil-based dry aniline paint or oil-based color paints is one of the best methods to darken linseed oil.

Firstly, use boiled linseed oil (BLO) because raw linseed oil can take months to dry. Also, prepare your soft clothes for applying the oil.

Linseed oil can harden with the addition of dry aniline paint. To avoid any mishap, prepare the surface you intend to paint before you start mixing the oil.

To darken linseed oil with oil-based dry aniline paint, use 100ml of linseed oil and 5ml of aniline paint. The mixture should be mixed with water and transient over amber.

Use soft clothes to apply the darkened linseed oil. Instead of a single thick coat, go for multiple thin coats. Continue applying thin coats of the mixture until the surface is fully coated.

Adding Wood Stain to Linseed Oil

The step-by-step process for darkening linseed oil with wood stain is similar to the process of using aniline paint.

However, there are some differences. In this process, you should use gel wood stains since they are compatible with materials like wood, metal, and fiberglass.

Prepare the surface you want to coat because this mixture has to be mixed and applied quickly.

Mix linseed oil and any suitable gel stain like Minwax. Make sure you follow the instructions regarding mixture ratios.

To build up the color of your choice, make a moderate mixture of Minwax stain or any gel stain of your choice. Next, use a cloth to spread the mixture over the surface you want to coat, then rub it on. Use a thin coat and apply the mixture for 3-5 days. After applying the mix each day, make sure to buff the excess. This prevents the surface from getting gummy and sticky.

How to Apply Linseed Oil to a Car?

When applying linseed oil to a surface, you must consider the surface material. For example, the process for applying linseed oil to a car and wood is quite different. Since car body panels are metal, there are things you should do to prepare the surface.

Remove Visible Rust

Often than not, linseed oil is used on cars with rust. The first step in preparing the car’s body panels is to remove the rust. After removing the rust, you can follow up by washing rust-affected areas with automotive soap.

Wash the Car

Use detergent to wash the entire car exterior. This step removes rust particles and dust on the car.

Gently Sand the Car

If there’s still some rust left on the car, use sandpaper and gently sand the rusted areas.

Apply Linseed Oil

After cleaning the car, you can now apply oil. Use a soft cloth to apply thin coats of oil to the vehicle. Once you’ve gotten your desired coat, lightly buff the car with a clean cloth to remove excess oil.

Limitations of Linseed Oil

For some time, linseed oil has gained enormous popularity in woodworking because of its advantages.

As a finish, linseed oil is water resistant, flexible, and easy to apply. In addition to that, it improves the grain of the wood. However, like every other thing, linseed oil has limitations.

It dries slowly: Raw linseed oil is known to take months to dry down. When compared to other finishes, linseed oil takes too long to dry. Boiled Linseed Oil (BLO) which is just the processed variation, dries faster.

Lack of UV Inhibitors: Despite being a popular choice of finish, linseed oil does not have UV Inhibitors. As a result, surfaces coated with linseed oil need more frequent maintenance. Finishes with UV inhibitors are generally better for the environment and our health. They are also more durable and free of chemicals like Volatile Organic Compounds (VOCs).

It supports the growth of mildew: While mold is not uncommon in cars, you can’t say it’s desirable. Linseed oil can promote the growth of microbial organisms like mildew, primarily if used inside the vehicle to restore faded car plastics.

Safety Measures for Handling Linseed Oil

While linseed oil is non-toxic and organic, there are specific safety measures you must follow when handling it. Linseed oil can cause severe irritation to the skin and eyes.

To avoid irritation, use protective gloves and clothing. And wear a quality face mask to protect your face and eyes. Finally, ensure your workspace is well ventilated; store linseed oil in cool, dry areas too.

Common Mistakes Made While Darkening Linseed Oil

We have outlined steps to darken linseed oil for your project. But a few common mistakes can persist and ruin your work, turning everything into a mess. Here are some common errors in darkening linseed oil:

Inaccurate Measurements

The first step to achieving blemish-free work in anything is getting your measurements correct. While darkening linseed oil, make sure you follow the right oil-to-paint or stain ratio. If your measurements are inaccurate, you will most likely end up with a streaky coat.

Ignoring Safety Precautions

We have already established how important it is to follow safety precautions. Most times, people ignore safety precautions, and it doesn’t end well. Although linseed oil is not noted to have any toxicity, you are advised to protect your hands and eyes while handling it.

Not Following Clearly Defined Steps

We’ve given you steps to darken linseed oil in a way that is easy to follow. When working on a project, it’s much better to follow clearly defined steps.

Ignoring the Manufacturer’s Instructions

Most people are guilty of ignoring the manufacturer’s instructions. When trying a process for the first time, it helps to follow the manual. Failure to follow the manufacturer’s instructions can cause low efficiency and safety hazards.

You can use any of the two aforementioned methods to darken linseed oil and be assured of good results.

Although, you have to follow the steps correctly and make sure you use Boiled Linseed Oil (BLO) rather than raw linseed oil. Which one of these best methods will you be using for your project?