Hardwax Oil Finishes Explained

Wood finishes come in all sorts of varieties, but one of the most natural looking is hardwax oil. It's made from a mix of vegetable oils and waxes and doesn't form a plastic film on the wood, which can obscure its natural beauty. Hardwax oil finishes have been gaining popularity in the North American market for their aesthetically pleasing and natural look.

When it comes to hardwax oil vs polyurethane, there are a few key differences. Hardwax oil is more breathable, meaning it won't trap moisture in the wood and cause warping or cupping over time. It's also less likely to yellow with age, making it a good choice for lighter woods. Polyurethane, on the other hand, is more durable and waterproof, making it a good choice for high-traffic areas or areas that are likely to get wet.

Hardwax oil can be applied by brush, roller, or rag, and doesn't require any special equipment. It's important to note that hardwax oil should not be used on floors that are already finished with wax, varnish, shellac, or lacquer.

Uses of Hardwax Oil

Hardwax oils may be used to protect and beautify wood surfaces. Some common applications include wood flooring, millwork, furniture, countertops, cabinetry, toys, food presentation platters, and other wood-like substrates. Hardwax oils can be used both indoors and outdoors.

When using hardwax oil on wood surfaces, it is important to follow the manufacturer's instructions. In general, the surface should be clean and free of dirt and debris before application. The hardwax oil can be applied with a brush, roller, or cloth, and should be allowed to dry according to the manufacturer's instructions.

Formulation

Oils

The hardwax oil is usually a blend of different oils. The ratio of the oils can be fine-tuned to create a product with specific characteristics. For example, adding more linseed oil to the formulation will make the hardwax oil more liquid and easier to spread. Conversely, adding more tung oil will make the hardwax oil thicker and more difficult to spread.

Wax

The ingredients that are used in hardwax oil also contain natural hardening waxes. These include beeswax and carnauba wax. Hardening waxes help to protect the wood and give it a harder surface.

Single-Component or Two-Component

Single-component hardwax oils are products that dry and cure by reacting with oxygen present in the air. This curing process may take up to 30 days before a complete cure has taken place. During the curing period, hardwax oils should not be exposed to liquids.

Two-Component hardwax oils are unique in that they use two curing processes to achieve hardness. The first is the standard oxidative curing process that all hardwax oils use. However, the second process is unique to two-component hardwax oils and comes from the additive component.

This additive component causes the oil resin to cure at a much faster rate than just the oxidative (airdrying) process alone. As a result, two-component hardwax oils typically dry and cure in less than a week. The benefits of using a two-component hardwax oil are that it provides a harder and more durable finish than a single-component hardwax oil.

VOC Content

Volatile organic compounds (VOCs) are organic chemicals with a high vapour pressure at normal room temperature. Volatility is the ability of a substance to evaporate or sublimate from its liquid or solid form and enter the ambient air, as evidenced by a low boiling point. VOCs are numerous, varied, and ubiquitous.

They are emitted by a wide array of products numbering in the tens of thousands. VOCs typically are not acutely toxic, but some may have long-term health effects such as cancer or other chronic respiratory ailments. Additionally, VOCs can contribute to air pollution. Some hardwax oils contain 0% VOCs while others contain differing amounts.

Solid Content

When no solvent evaporates, the product is considered a 100% solids product. This means that the finish is entirely solid, and there is no liquid remaining. Hardwax oil products with high solids often translate into high yields and good coverage/spread rates. This is because there is more material to work with, and less chance of the finish being too thin or running off the surface. High solid content also means that the finish will last longer and be more durable. This is because there is less opportunity for the finish to break down over time due to evaporation or other causes.

Chemical Sensitivities

Chemical sensitivities are a common concern for many people when it comes to wood finishing products. Some people are sensitive to the chemicals in wood finishes, often to the ingredients that evaporate. 0% VOC hardwax oil finishes are a great option for people with chemical sensitivities, as they do not contain any volatile organic compounds.

Some manufacturers may have certifications available that certify their product to be food-safe, safe for use on wood toys, or certified for healthy indoor air quality. When choosing a hardwax oil finish, it is important to consider the ingredients and VOC levels in order to find a product that will work best for you and your project.