DIY Finishing - Finishing Techniques

Wax or wood oil? What to refresh varnished or painted furniture with

"I understand that tung oil is very good. Can I use it to refresh wooden furniture?" It was a piece of furniture made of varnished wood. Very good tung oil, but not for already varnished wood. I explained why oil applied over the varnish coat will do nothing to help the wood, and recommended using furniture wax, after first cleaning the furniture of the dirt accumulated over time. As wax and oil are often equated, I think a few clarifications are necessary regarding the behavior of each in relation to wood. It is also good to know that wax can be used to refinish painted or varnished furniture, not linseed or tung oil.

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Natural oils are applied directly to the wood - this protects and enhances the wood grain

The natural products used to protect wood and finish furniture are oil, wax and waxes. shellac-ul. Wax and oil are often mentioned together and therefore there is sometimes confusion about their behavior towards wood, which is considered similar. Especially as they both protect against water, one of wood's main enemies.

The oils are applied directly to the wood in order to penetrate as deeply as possible and protect it from the inside. Many say that the oil "feeds" the wood, and perhaps that's not entirely wrong when you consider that oiled wood retains a fresh, lively appearance. If the treatments applied to the oils (boiling) have greatly increased their viscosity, it is recommended to dilute them with turpentine oil, even 1:1, precisely to ensure that the wood absorbs as much oil as possible. The deeper it penetrates, the better and longer the wood is protected.

The oil's yellow, sometimes golden-brown color, oily texture and deep absorption specifically color the wood and highlight its grain in a unique way. It is virtually impossible to replicate the effect using varnish and varnish, and we cannot achieve it if the oil is applied over layers of paint or varnish. The appearance is very natural and because there is no film or only a very thin film, the wood retains its natural look.

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Main differences between linseed and tung oil

The most commonly used natural oils for wood are linseed and tung oil. Despite their fairly similar appearance there are differences between them, the most important being their ability to penetrate as deep into the wood as possible and their ability to dry. Linseed oil has a smaller molecule than tung oil and therefore penetrates deeper into the wood, tung oil always needs to be diluted when applying the first coat.

As for drying, tung oil dries in contact with air, linseed oil does not. Linseed oil, applied in a thicker layer, does not dry even if it is boiled and has added siccatives (drying chemicals). After application to the wood and 20-30 minutes for absorption, the surface should be wiped to remove excess. If it is not removed, the excess becomes gummy and sticky, difficult to remove, and is a dirt-binding factor. This is another reason why linseed oil is not recommended over varnish or paint.

Tung oil polymerizes in contact with oxygen in the air, dries and forms a very resistant film, even outdoors. It is a long process, however, and the film is completely dry 30 days after application. Applying tung oil to a varnished surface is not justified because the wood will not stand out, and the thin layer of oil, even if it dries at some point, will have enough time to bind all the dust in the air. In addition, natural tung oil is expensive, and refinishing old furniture can be done more effectively with much cheaper materials.

Wax protects on the surface and is a solution for refreshing the shine of furniture

Unlike oils, wax is solid and penetrates very little into the wood. For good adhesion, the wood needs to be rubbed with a cloth soaked in wax for a long time, or the wax needs to be warmed beforehand to make it more fluid. The main purpose of waxes is to protect surfaces, including wood, by causing water to run off.

There are many types of wax used for wood or furniture, ranging from natural waxes, such as beeswax or carnauba (a type of palm) wax, to paraffin waxes and synthetic waxes. Most commercial waxes are often blends, as natural waxes are quite rare and expensive. When they are intended to coat wood, linseed oil or synthetic oils, rarely tung oil, are added to the mixture to have a component that penetrates into the wood, thus increasing the protection offered.

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There are special furniture waxes that contain only volatile oils such as turpentinein order to ensure the necessary viscosity for application. By evaporating the oils, the wax becomes solid, can be polished, and thus protects and beautifies the surface with a pleasant, silky sheen. You can also make your own furniture care wax. Find recipes and instructions here.

Recommendations for refreshing lacquered furniture

In conclusion, use furniture waxes, not wood oils, to refresh old lacquered or painted furniture. Before waxing, clean the furniture of accumulated dirt. At its simplest, clean with water and dishwashing detergent. Wipe with a cloth soaked in this solution and wrung out well. Finally, clean with clean water, again with the cloth wrung out well. The water must NOT be boiling. After cleaning, the furniture should be left to soak for at least 12 hours, preferably overnight. Then wax with a soft cotton cloth. After at least 30 minutes, polish with a clean soft cotton cloth or a piece of felt. Movements are circular at first, along the fiber at the end.

I hope you find the information useful. As always, additions are welcome. And if you have any questions or queries, leave them below in the dedicated space. I'll be sure to reply.

About the author

Mihaela Radu

Mihaela Radu is a chemical engineer but has a great passion for wood. She has been working in the field for more than 20 years, wood finishing being what defined her during this period. She gained experience working in a research institute, in her own company, as well as in a multinational. She wants to continuously share her experience with those who have the same passion - and more.

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    • Hello!
      Chestnut wood dries very slowly. The time can be more than double that of other species. The drying time depends on how much heartwood it has. This means that the older it is, the harder it will dry. This is due to formations in the pores of the heartwood called tiles. that don't let water out. Basically, the tiles clump together in the sectioned area, blocking the water out. It can take more than 6 months, even more than a year, before the moisture reaches 30% (equilibrium moisture). Then the humidity drops even more slowly.
      There are specialists who say that cutting 20-25 mm caps (rounds) at the ends every 1-2 months speeds up drying.
      The good news is that chestnut wood is very resistant to rot, so there won't be any problems due to high humidity. Beware of insects though, it is not as resistant.

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