No, tung oil darkens the natural hue of walnut wood not at all. However, you can use its darker variant to bring out the full extent of its color. If used correctly, pure tung oil can further accentuate the gorgeous grain patterns of walnut wood and will not discolor or become dull with age.
Tung oil is loved for the fact that it's “green,” and all natural, containing no VOCs. It offers a natural look and won't create a glossy one, and it won't darken or mold.
What Are The Basics of Getting a Fantastic Wood Finish? The solid walnut top, above, is a slightly different story. I finished it with just a hand-rubbed tung oil varnish, applying 8 coats to protect the top surface while giving the walnut a gorgeous, natural warm glow, too.
Color and Finish
A pure tung oil finish has a honey-like color that brings out the natural beauty in your wood grain, while linseed oil starts out with a similar slightly yellow hue that fades to a darker orangey finish over time.
Traditionally, tung oil has been used on oak to maintain its colour, however, if you wish to darken the oak then hard wax oil is preferable. Danish oil is popular, historically, as a finish on oak as it brings out its rich tones, as well as preventing staining to the surface.
Pros & Cons of Tung Oil as a Wood Finish
It's all natural, non-toxic, and eco-friendly, and it doesn't yellow as much over time as common finishes like linseed oil, nitrocellulose lacquer, or varnishes like polyurethane. On the other hand, tung oil is expensive and susceptible to water rings, stains, and scratches.
Oils such as the clear Polyx®-Oil accentuate the natural colour and grain of the wood (permanent wet-look). Polyx®-Oil Effect (3044 Raw) counters this exaggeration of the wood's colour, leaving the surface looking natural in it's new or raw condition.
There are many reasons why people love tung oil for their projects, and one of the most popular is its flexible, durable, food safe, and protective waterproof finish that doesn't mold, darken or go rancid.
After the final coat has been applied and the excess removed leave for 24 hours and wipe over again to aid drying and remove any oil that may have surfaced. We recommend a minimum of four coats, more coats will be required for porous or external surfaces.
We recommend using tung oil for walnut. This type of oil will darken the grain, enhancing and protecting the wood.
When tung oil dries, it dries from the outside in. If there is too much tung oil left on the surface, or if the first coat is not allowed to cure before a subsequent coat is applied, there will be unreacted tung oil under the surface layer.
To get maximum protection, you should apply 3 coats of full-strength tung oil. You should also have sanded with 0000 steel wool the day after applying each coat. As an optional step, you can use thin the first coat of tung oil by 50% or more using turpentine or naphtha.
Tung Oil Re-coating – Sanding Between Coats
Typical dry times are between 2 and 7 days before re-coating. You can test to see if the surface is ready to be re-coated by doing a light sanding in a small area with a 400-600 grit sandpaper. If the sanding produces a fine white dust you are good to go.
Pure Tung Oil will cure into a 'permanent' film unlike some other raw oil finishes. Permanent is in quotes because it will be worn away with use, cleaning, and exposure. Outdoor surfaces as well as heavily, or frequently used surfaces will need a touch up sooner than lightly used surfaces.
Raw Tung Oil is a VERY SLOW drying oil. It takes upwards of 6 weeks for raw Tung oil to cure and often remains sticky during that 6 weeks.
If you leave too much on the surface, or put on the coats too quickly, you run the risk of the tung oil developing a "frosty" look where some of the tung oil has turned white. The same thing would happen if you dried to add driers to tung oil.
Woodworking Expert - Michael Dresdner: "Yes, I would put a coat or two of oil-based polyurethane on for more durability, and it is fully compatible over the dried tung oil (or linseed oil, or any other drying oil for that matter.)
Wipe-on poly or spar varnish will work on top of tung oil. This should protect the top from water damage, but it will show wear, so you will need to reapply every year or so.
Tung oil hardens upon exposure to air (through polymerization), and the resulting coating is transparent and has a deep, almost wet look. Used mostly for finishing and protecting wood, after numerous coats, the finish can even look plastic-like. Related drying oils include linseed, safflower, poppy, and soybean oils.
Tung oil Uses
Because it doesn't darken and is resistant to mould, it is widely used on interior and outdoor furniture, wooden toys, cabinets and musical instruments such as guitars and more.
Walnut oil is a favourite among spoon carvers and green wood workers. It is pale and will not change the colour of your piece.
So if you're looking for a wood oil with either a matt finish, or being 100% natural and environmentally friendly is key, then Tung Oil is the best bet. Otherwise, for most surfaces we would actually recommend Danish Oil as it dries quicker and provides a harder wearing finish to wood.