Tung oil, prized for its durability and natural beauty, has been a favorite among woodworkers for centuries. However, its notoriously slow drying time can be a major drawback. This is where citrus solvent comes in, often touted as a way to speed up the drying process and improve penetration. But is this combination truly beneficial, and are there any drawbacks to consider? Let's delve into the details.
What is Tung Oil?
Tung oil is a natural drying oil extracted from the seeds of the tung tree ( Vernicia fordii). It's known for its excellent water resistance, durability, and the beautiful, lustrous finish it imparts to wood. The oil penetrates deeply into the wood grain, protecting it from moisture and UV damage. However, its natural drying process is slow, often taking days or even weeks for complete curing.
What is Citrus Solvent?
Citrus solvent, also known as d-limonene, is a natural solvent derived from citrus peels. It's a powerful cleaner and thinner, often used in wood finishing to improve the flow of oil and reduce viscosity. Its popularity stems from its relatively low toxicity compared to many petroleum-based solvents.
Does Citrus Solvent Speed Up Tung Oil Drying?
This is a complex question. While adding citrus solvent to tung oil can seem to speed up the drying process by thinning the oil and allowing for better penetration, it doesn't actually accelerate the chemical reaction that causes the oil to cure. Instead, it speeds up the evaporation of the solvent and some of the thinner components of the tung oil. This leaves a thinner, potentially more vulnerable coating behind, which may not provide the same level of protection as pure tung oil.
What are the benefits of using citrus solvent with tung oil?
- Improved Penetration: The thinner consistency allows for better penetration into the wood, potentially resulting in a more durable finish.
- Easier Application: The reduced viscosity makes the oil easier to apply, particularly on intricate carvings or detailed woodwork.
- Less Tacky Finish: The quicker evaporation of the thinner components may result in a less tacky surface during the drying process.
What are the drawbacks of using citrus solvent with tung oil?
- Reduced Durability: The faster evaporation can lead to a thinner film with less protection against water damage and wear.
- Potential for Cracking: A thinner film is more prone to cracking over time, especially in environments with fluctuating temperature and humidity.
- Not a True Drying Accelerator: The solvent doesn't actually speed up the chemical curing process of the tung oil. This means the final cure time might not be significantly shorter.
How to Use Citrus Solvent with Tung Oil (If You Choose To)
If you decide to use citrus solvent with tung oil, it's crucial to do so sparingly. A general guideline is to start with a ratio of no more than 10% citrus solvent to 90% tung oil. Always test the mixture on a scrap piece of wood first to assess the results before applying it to your project.
Is it Necessary to Use Citrus Solvent with Tung Oil?
Many experienced woodworkers find that the benefits of using citrus solvent with tung oil are outweighed by the potential drawbacks. The slow drying time of pure tung oil is a characteristic, not a flaw. The resulting finish is exceptionally durable and protective. For a faster drying time, consider other oil finishes or alternative methods like wiping on multiple thin coats.
What are the alternatives to Tung Oil?
Many other oil-based finishes offer faster drying times and excellent durability, such as linseed oil, walnut oil, or even commercially available tung oil finishes which often contain added driers to expedite the curing process.
Can I use other solvents with Tung Oil?
While citrus solvent is popular, using other solvents with tung oil is generally not recommended. Many petroleum-based solvents can negatively affect the curing process and the final finish. Stick to the recommended thinners for your specific type of tung oil if a thinner is needed.
By understanding the properties of both tung oil and citrus solvent, you can make an informed decision about whether or not to incorporate the solvent into your finishing process. Remember that patience is often rewarded with a superior, long-lasting finish when using pure tung oil.
