What Are the Dangers of Using Walnut Oil As a Finish?

Oil from pressed walnuts is a finish for furniture and utensils.

Walnut oil is one of many finishes you can use for wood projects. Made by pressing walnuts, it hardens slowly, creating a coating for your bowl or chair to preserve it. You should exercise some caution in using walnut oil, however.

Rancidity

All vegetable finishes, such as walnut oil, contain unsaturated fats. This can cause it to go bad or become rancid. Rancid walnut oil has a strong smell and taste, which can be objectionable to people. It also can make food taste off, even if there are no immediate health effects.

Combustion

The unsaturated fat in walnut oil also can cause a problem with combustion. This fat oxidizes and dries when it is exposed to air. If this drying occurs quickly, it gives off heat and there is a chance the oils will ignite. This is more likely to occur with rags than the oil itself. Be sure to dispose of oily rags properly to minimize risk.

Allergies

Allergies are also a concern with walnut oil. Many people have allergies to tree nuts, including walnuts, and should not come in contact with products made from them. For people without nut allergies, walnut oil has few dangers as a finish, and these can be lessened by taking proper care of the oil and the implements it comes into contact with.

References

• Art Purveyors: Important Information on Rancidity and Vegetable Oils
• Woodworker's Journal: Spontaneous Combustion