A drying oil extracted from the seeds of the tung tree, pure tung oil by the Real Milk Paint Co. offers a water-resistant finish that doesn’t yellow or go rancid with time. Tung oil, also known as Chinawood oil (derived from where the tung tree grove is located), is a favorite finish solution among hobbyists and woodworking enthusiasts due not only to its environmentally friendly formulation that contains no additives or distillates but also because it dries quickly to a flexible, food-safe finish. Unlike boiled linseed oil or other finishes, tung oil works on numerous surfaces besides finished, painted and bare wood, providing a versatile top coat for a plethora of DIY projects.
The key to getting the results you desire, however, comes down to knowing how to apply tung oil properly for the task at hand.
Tung Oil and the Janka Hardness Scale
The type of tung oil and how to thin it down for your projects typically depends on where the wood you’re using falls on the Janka Hardness Scale. This scale helps you figure out how well wood species generally withstand wear, dings and dents and how hard or easy it is to nail, sand, saw or screw the wood type in question.
Likewise, the Janka Hardness Scale predicts how well tung oil absorbs into various species of wood. For example, tough hardwoods such as pecan and mahogany range from 1500 to 3510 on the Janka Hardness Scale, making a mixture of two parts solvent and one part Tung Oil a winning combination.
Rough-sawn light woods such as red cedar, basswood and western hemlock, however, have a much lower rating, allowing use with undiluted Pure Tung Oil or Dark Tung Oil. Woods on the lighter side between the two extremes work well with Half & Half, Dark Half and Outdoor Defense Oil, while woods on the harder side easily absorb Hemp Oil.
Uses for Tung Oil
High-quality Tung Oil from the Real Milk Paint Co. works well for numerous projects involving porous surfaces like wood, concrete, brick, unglazed tile, etc. The food-safe formulation makes it a great choice for oiling cutting boards and wooden spoons, and it works equally well on concrete and butcher blocks. It provides a natural way to finish countertops and kitchen cabinets that avoids potentially hazardous products like varnish and lacquer, and it delivers extra protection to wood surfaces covered with milk paint. Some uses woodworkers, artists and tradesmen have for this oil product include:
- Sealing interior brick fixtures like fireplace mantels
- Waterproofing outdoor deck and patio furniture
- Polishing boat or canoe oars for water resistance
- Preservation for metal arts and crafts projects
How to Thin Tung Oil
Tung Oil finish is a rather thick medium, so in many instances you’ll need to thin it down before use. Many people mix tung oil with oil-based thinners such as turpentine, mineral spirits, paint thinner or naphtha, but better alternatives exist that are far more eco-friendly.
For a “greener” finish solution, instead mix tung oil with all-natural thinners such as citrus solvent for tung oil or odorless mineral spirits by the Real Milk Paint Co. Do not use a mineral spirit or odorless mineral spirit marketed as “green”, “eco-friendly”, or similar verbiage. These do not mix with the tung oil and will create adverse effects on your finish.
For added convenience, we offer a premixed Citrus Solvent and Pure Tung Oil formulation with our Half & Half line so you don’t have to mix this oil product at all. Keep in mind that Pure Tung Oil also works well at full strength for some projects and should go on smoothly so long as you apply thin coats as evenly as possible. Since Pure Tung Oil doesn’t go rancid, you can store any leftover mixture for future projects for economical use.
Prepping Surfaces for Tung Oil
The first thing to look for when using tung oil is making sure your material is porous and doesn’t have any other kind of existing finish on it. This would need to be removed before proceeding.
The next step to prepping wood surfaces for tung oil application is cleaning. If you wish to treat a bare wood surface, wiping it down with a damp cloth to remove any lint should suffice. For surfaces covered in dirt or grime, however, a quick once-over with Tri-Sodium Phosphate should cut through for easy cleanup.
After the piece is dry and clean, sanding with fine to medium grit sandpaper will bring up the grain of the wood. Tung oil absorbs into the cracks and crevices of wood grain, so raising up those unique details a bit lets it seep deeper for superior results.
Once you have the bare wood surface or porous surface ready for tung oil application, you just need a couple of rags or a bristle brush and rag to begin your project.
How to Apply Tung Oil
Tung oil is known for its deep absorption into porous surfaces, which can beautifully enhance the natural grain and character of the wood. However, proper application is critical to achieve that perfectly sealed and lustrous finish. Follow the detailed steps below for the best results:
Step 1: Choose the Right Applicator
Start the process with the right tools. Opt for a clean, dry, lint-free rag for a more controlled rub. Alternatively, a natural bristle or foam brush can be used for an even stroke. Apply a liberal first coat of tung oil using your chosen applicator to ensure thorough coverage.
Step 2: Allow Absorption Time
Once the first coat is generously applied, let the tung oil sit and absorb into the wood. This absorption process is essential for achieving a deep seal. Give it up to 40 minutes, ensuring the porous surface takes in the first coat effectively.
Step 3: Apply the Second Coat
Repeat the application process from Step 2, ensuring you spread another even coat of tung oil onto the surface. Let the second layer be absorb into the wood just like the first.
Step 4: Saturate the Surface
Continue applying tung oil in subsequent coats, repeating the aforementioned steps. With each application, observe the wood’s absorption rate. Keep adding coats until the surface is fully saturated and the oil no longer sinks into it. After the final application, give it a resting time of at least 40 minutes.
Step 5: Clear Excess Residue
Post-application, there might be spots where the tung oil finish has pooled or puddled. Using a fresh, dry, soft rag, gently wipe away this excess oil to ensure a smooth and even finish.
Step 6: Let it Cure
The final and one of the most crucial steps is to let the oiled surface cure properly. Before putting the surface to use, ensure it’s fully dry and cured to maintain its sheen and durability.
Applying Pure Tung Oil to Butcher Blocks
Due to a formulation that’s safe for food contact, Pure Tung Oil makes a great choice for oiling up butcher blocks. The application process helps protect cutting boards and countertops from damage, mold and mildew, and it imbues a gorgeous flat finish that brings out the beauty of high-quality wood. The steps for applying Pure Tung Oil to butcher blocks includes:
- Mix one-part Pure Tung Oil to one-part Citrus Solvent. By mixing the two products, you boost the absorption of the oil into the wood.
- Sand your butcher block, up to 220 fine grit sandpaper, to create an even surface for Pure Tung Oil application. During the sanding process, be sure to buff out any scratches, and pay special attention to duller areas.
- Wipe the surface down with a tack cloth to remove any dust and debris.
- Use a clean, dry rag to apply the Pure Tung Oil/Citrus Solvent mixture to your butcher block. Once applied, give the mixture ample time to soak into the wood.
- Once the mixture has soaked into the wood, apply another coat, waiting up to 40 minutes between coats.
- Repeat steps 4 and 5 until the wood no longer absorbs the Pure Tung Oil/Citrus Solvent mixture.
- When the wood no longer absorbs the oil, use another clean, dry rag to wipe all the oil away.
- Wipe away any pooled oil that oozes out of the wood grain over the next few weeks.
- Wait at least a month before using the butcher block for heavy-duty tasks, as Pure Tung Oil typically takes about 30 days to properly cure.
Curing Surfaces After Tung Oil Application
Drying oils such as Pure Tung Oil sometimes take up to 30 days of drying time to completely cure, depending on the amount used. Waiting a minimum of 7-10 days before using the surface is recommended. This water-resistant sealer offers a polymerized finish achieved without additives or distillates to speed up the process. When curing items finished with Pure Tung Oil, keep in mind they cure best in warm, well-ventilated areas. You should keep everything off the surface while it’s curing to prevent it from suffocating.
If you’ve finished countertops or butcher blocks with tung oil, avoid use for 7 to 10 days to ensure proper curing. During the first 5 days rub the top with a clean cloth to pick up any seepage. While you can use most tung oil-finished items during the first 15 days of the curing process, you shouldn’t allow those surfaces to accumulate dirt or let liquids puddle on them. After that initial 15 days, however, durability increases. Keep in mind that some tung oil may rise to the surface during the curing process due to expansion. If you find any excess oil seeping up through the grain of the wood on a tung oil finish, simply remove it with a rag and continue the use of your finished product.
Once you have the hang of how to apply tung oil, it’s a skill you can use over and over again. Whether you’re a crafter making custom farmhouse decor, a woodworking aficionado who makes your own furniture or a craftsman seeking a water-resistant wood finishing option, the Real Milk Paint Co. has you covered with high-quality wood wax and wood cutting board finishing oil products that help your merchandise or belongings look their best, even with time and use.