wood finishing process

A Comprehensive Guide to Penetrating Oil Finishes

Wood has an innate beauty that can be accentuated and protected with the right finishing touch. Among the various options available, penetrating oil finishes have gained popularity for their ability to enhance the natural characteristics of wood while providing durable protection. In this comprehensive guide, we will delve into what penetrating oil finishes are, how many coats are recommended, what makes them unique, and the proper application process to ensure your wood projects shine with lasting beauty.

What are Penetrating Finishes?

Penetrating finishes, as the name suggests, work by seeping into the wood fibers rather than forming a protective layer on the surface. Unlike surface finishes, such as varnishes or lacquers, penetrating oil finishes enhance the wood’s natural appearance while offering protection against moisture, stains, and wear.

Key Characteristics of Penetrating Finishes:

Enhanced Wood Grain:

  • Penetrating oil finishes highlight the natural grain and texture of the wood, creating a warm and organic appearance. This is particularly appealing for those who appreciate the authentic beauty of wood.


  • Unlike some film-forming finishes, penetrating oils allow the wood to “breathe.” This characteristic is crucial for certain applications, such as outdoor furniture, where the wood needs to expand and contract with changing weather conditions.

Easy Maintenance:

  • Penetrating finishes are relatively easy to maintain. If the wood starts to show signs of wear or dullness, a fresh application can rejuvenate the appearance without the need for extensive sanding or stripping.

How Many Coats of Penetrating Oil?

The number of coats required for a penetrating oil finish depends on various factors, including the type of wood, the desired level of protection, and the manufacturer’s recommendations. Generally, applying multiple thin coats is more effective than a single thick coat. Here’s a breakdown of the coating process:

First Coat:

    • The initial coat is absorbed deeply into the wood, helping to nourish and protect from within. This coat is crucial for establishing a strong foundation for subsequent layers.

    Additional Coats:

    • Subsequent coats build upon the foundation laid by the first application. Two to three coats are often recommended to achieve optimal protection and enhance the wood’s natural beauty.

    Sanding Between Coats:

    • Depending on the product and wood type, lightly sanding between coats may be recommended. This ensures proper adhesion and a smoother finish.

    Manufacturer Guidelines:

    • Always refer to the manufacturer’s guidelines for the specific penetrating oil finish you are using. They may provide recommendations based on the product’s formulation and intended application.

    What is a Penetrating Oil?

    A penetrating oil is a type of finish specifically formulated to penetrate the wood’s surface, providing protection and enhancing its natural beauty. The composition of penetrating oils varies, but they often contain a combination of drying oils, solvents, and sometimes additives such as UV stabilizers. Here are some key features of penetrating oils:

    Drying Oils:

    • Commonly used drying oils include tung oil, linseed oil, and danish oil. These oils polymerize when exposed to air, creating a protective film within the wood fibers.


    • Solvents in penetrating oils facilitate the penetration of the finish into the wood. As the solvent evaporates, the drying oils are left behind, forming a protective layer.


    • Some penetrating oils include additives like UV stabilizers to protect the wood from sun damage and extend the life of the finish.

    How Do You Apply Penetrating Oil Finish?

    The application of penetrating oil finish is a crucial step in achieving the desired results. Follow these steps for a successful application:

    Surface Preparation:

    • Ensure the wood surface is clean, dry, and free of any existing finishes. Sand the wood to a smooth finish, starting with a coarse grit and progressing to finer grits.

    Stir the Finish:

    • Thoroughly stir the penetrating oil finish before application to ensure even distribution of the components.


    • Use a brush, lint-free cloth, or applicator pad to apply the penetrating oil evenly on the wood surface. Work in the direction of the wood grain to promote proper penetration.

    Allow Absorption:

    • Let the first coat absorb into the wood for the recommended time specified by the manufacturer. This allows the oil to penetrate deeply and nourish the wood fibers.

    Wipe Excess:

    • After the absorption period, wipe off any excess oil with a clean, dry cloth. This helps prevent over-saturation and ensures a smooth, even finish.

    Subsequent Coats:

    • Apply additional coats following the same process, allowing proper drying time between each coat. Lightly sand between coats if recommended by the manufacturer.

    Cure Time:

    • Allow the final coat to cure for the recommended duration before subjecting the wood to heavy use or exposure.


    Penetrating oil finishes offer a beautiful and protective solution for wood surfaces, showcasing the material’s natural elegance while safeguarding it from the elements. By understanding what penetrating finishes are, how many coats are needed, the composition of penetrating oils, and the proper application process, you can confidently embark on enhancing your wood projects. Whether you’re refinishing furniture, cabinetry, or outdoor structures, penetrating oil finishes provide a timeless and durable solution that celebrates the inherent beauty of wood.