Varnish versus Oil

Thursday, 5th September 2024

Protecting wooden surfaces from wind, weather and everyday wear has always been a challenge. The choice between varnish and oil can significantly impact the look, durability, and maintenance of your project.

Varnish

Varnish is a hard finish that provides a protective layer over wood. It’s typically made from a mixture of resins, oils, and solvents. When applied, varnish dries to form a tough, durable coating.

Types of Varnish

  • Polyurethane Varnish: Offers durability and resistance to chemicals, heat, and scratches. Ideal for high-traffic areas.
  • Spar Varnish: Designed for outdoor use, it provides flexibility and UV protection, making it suitable for boats and exterior wood.
  • Alkyd Varnish: Hard finish and gloss, used for furniture and cabinetry.

Pros and Cons 

  • Varnish is cheap, easy to apply and is resistant to stains and water. It's available in various sheens, from high gloss to satin. However, even the best varnishes will start to wear, and areas will need to be sanded down and additional coats applied, especially on well-used areas such as wooden floors. This can present the problem of having to satisfactorily match the existing colour tone. Another drawback with varnish is that it can crack and peel over time, thus increasing the number of times that you will need to maintain the surface.

Oil

Wood oil penetrates the wood and enhances its natural beauty. Unlike varnish, it doesn’t form a surface layer but instead soaks into the wood fibres.

Types of Wood Oil

  • Linseed Oil: One of the most traditional oils, providing a warm, amber tone. 
  • Tung Oil: Offers a water-resistant finish with a slightly darker hue. 
  • Danish Oil: A blend of oil and varnish.

Pros and Cons of Oil

An oiled wood offers a durable surface which resists water, dirt and stains. Oil enhances the wood grain and provides a rich, warm finish It's not as hard-wearing as varnish but when it requires reviving, the required finish is so much easier to attain. A very light sanding followed by a coat of oil and job done. An alternative to sanding is to use a spirit-based cleaner, just rub it gently over the wooden surface before applying the oil. 

The choice of oils on the market is huge. Look for oils that will give you a high level of protection and, if possible, ask for examples so that you can see the finished effect. 
Wax oils are another option for indoor woodwork, they work by holding the wax in a spirit base which only becomes solid when the spirit evaporates. Only one coat is required, and it takes around eight hours for evaporate to occur. It is odour free and avoids the need for hard polishing.

On surfaces where food is either eaten or prepared, e.g. hardwood worktops, remember to choose a protective oil that is suitable for these areas. For exterior use, there are oils on the market which offer protection for a variety of timbers, as well as some UV protection against the elements.

By understanding the properties of both varnish and oil and the specific needs of your woodworking project, you can select the finish that best enhances and protects your woodwork.