Untreated wood doesn’t tend to last long without at least some kind of oily wood preservative.
It doesn’t matter if that oil is naturally found in abundance inside wood grain (such as in Rosewood or Teak wood). Or whether a penetrating oil is applied directly via a wood finish (i.e. by soaking timber in Linseed oil or Danish oil).
Either way, oil not only enriches wood grain, it safeguards timber from moisture, damp, rot and decay. Making an oil finishing coat a key part of completing most woodwork crafts.
Now, there are two wood oils that’ll protect grain and leave your project with a superior satin finish to boot. And those two oils are Walnut oil and Tung oil.
But while these two wood finishes have very different origins… they’re more alike than you might think.
So, in this post, we’re going to dive into what makes these two oils so similar (and what really separates the two).
You’ll also learn why that grocery store Walnut oil should be avoided (and what type of Walnut oil you should really be using).
Plus, we reveal why you should always be cautious with certain types of Tung oil products (quick hint: a lot of them aren’t even made from Tung oil!)
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What Is The Best Oil For Old Wooden Furniture?
You should use a penetrating drying oil to rehydrate old wooden furniture.
These oils will soak into wood grain, coating lumber both inside and out. And once they dry and cure, they will form a hard resin coat on the surface.
So, wood finishes such as Linseed oil and Tung oil are some slow-drying favourites. Faster drying Linseed/Tung oil blends, (such as Danish oil and Teak oil), are great for furniture too.
Related Post: All About Danish Oil: Advantages and Disadvantages
Is Walnut Oil A Good Wood Finish Too?
Well, it is important to clarify here that, Walnut oil in its culinary form should never ever be used on wood.
Let me repeat that… the Walnut oil found on the shelves at your local grocery store, should not go anywhere near your woodworking project.
That is because this unfiltered version of Walnut oil has an expiry date. Which means it will go rotten and rancid if applied as a wood finish.
However, if you use a heat treated refined version of Walnut oil, then this particular type of this nut-sourced oil finish works very well as a wood preservative.
What’s The Difference Between Walnut Oil And Tung Oil?
Other than the plants they were sourced from, there is surprisingly little that really separates the two when it comes to wood finishing.
Both oil types are naturally sourced, of course. Walnut oil is extracted out of Walnuts. While Tung oil is naturally sourced too from the seeds of the Tung tree.
Tung oil is a natural drying oil. What that means is that this oil will naturally (and very slowly) dry, cure, and harden (through the process of polymerization).
Pure unrefined Walnut oil, however, is a non-drying oil…at least initially. So it has to be put through a heat treatment before it can be used as a wood finish.
This heated process filters out the proteins from Walnut oil (the proteins responsible for nut allergies). And once complete, you end up with a very refined drying oil product.
This drying Walnut oil version will then cure and harden into a fine looking finishing coat.
Related Post: Don’t Use Tung Oil On Your Cutting Board (Use This Instead)
But, Doesn’t Walnut Oil Go Rancid As A Wood Finish?
Well, heat treated refined walnut oil has had all of its proteins filtered out of it. And those proteins have an expiry date, (which is why pure grocery store walnut oil goes off).
But, once you’ve removed these proteins, the thin oily substance left behind won’t go rancid. This is why the only Walnut oil you should use on wood is the heat treated version.
And one of the best heat treated Walnut oils on the market for this is Mahoney’s Walnut Wood Finish. It’s all natural too, so it doesn’t have a load of harmful chemicals blended into it.
But, most importantly, it has been put through that all important heat treated filtration process that’ll keep this oil from ever going rancid.
Does Walnut Oil Darken Wood?
It won’t darken wood as this is a clear oil product. But to clarify, all oils darken wood somewhat. This will happen as a consequence of applying any liquid onto a wooden surface.
However, Walnut oil won’t darken wood any more than that.
What Kind Of Finish Does Walnut Oil Leave Behind? Walnut oil leaves a satin finish, one somewhat similar to the matte to light-satin appearance of a Tung oil finish.
And Will Tung Oil Darken Wood?
If you use a pure Tung oil product, then it won’t darken wood. That is because, just like Walnut oil, Tung oil is also a clear substance.
However, it is important to note that a lot of products marketed as ‘Tung oil’ simply aren’t. In fact, some of these products don’t even contain any Tung oil in them.
Instead, they are more of a Teak oil kind of blend made from different oils, varnish and thinners. End result? A so-called Tung oil product that is anything but.
Related Post: Can You Apply Teak Oil On Maple Wood? (Best Practice Revealed)
Now, with these faux-Tung oil finishes, you may find that they darken wood, (especially if they contain Linseed oil).
However, stick to a pure Tung oil drying oil, such as Liberon’s Premium Pure Tung Oil. You do that and you won’t have to worry about it darkening the natural color of timber.
You can find the latest prices for this pure Tung oil product over on Liberon by clicking here.
Which One Of These Oils Is Best For Wooden Spoons And Cutting Boards?
Both oils are food safe once they’ve cured all the way through.
So, Tung oil or Walnut oil can be used to seal wooden spoons. However, you will need to wait some time (anywhere from 2 to 4 weeks) for either oil finish to completely and wholly harden.
Only after that, will those oil coated wooden spoons be safe to use.
Still, as both oils are drying oils, neither one is ideal for conditioning and maintaining a cutting board. When it comes to cutting boards, you should instead use a pure food grade mineral oil product.
You can learn more about it in our post here: Walnut Oil Vs Mineral Oil: Which One’s Better For Your Cutting Board?
Is Tung Oil Safe For Cutting Boards? It is food safe only once it has wholly cured. Curing is when a drying oil undergoes a chemical reaction turning it into a solid substance. However, Tung oil’s curing process can take weeks to complete. But it is not suitable for a cutting board, as this oil is not a food grade oil.
Does Tung Oil Waterproof Wood Better Than Walnut Oil?
Neither Tung oil nor walnut oil are wholly 100% waterproof. They aren’t even the best water-resistant wood finishes you can use, either.
Still, this is pretty much the case with most penetrating oil finishes. That is because the job of an oil finish is to be more of a wood preservative, than a 100 % waterproof sealant.
If you want to waterproof wood, you will need to add a waterproof top coating sealer, such as polyurethane. Using a top coat sealant is key if you really want to make either a Walnut oil or Tung oil finish really durable.
Related Post: Can I Apply Water Based Polyurethane Over Danish Oil? (Solved!)
Is There Really No Difference Between Walnut Oil And Tung Oil?
Well, there are in fact two main areas where these two drying oils diverge from one another:
Oil Viscosity/Thickness:
Heat treated Walnut oil is a lighter thinner type of oil than Tung oil. This means that it may be able to sink deeper into wood grain than Tung oil.
However, it also means that wood will absorb this thinner oil really fast, so you will need to apply more coats of it.
So, while 2-3 coats of Tung oil is more than enough for most wooden surfaces, you will need around 4-5 coats of a drying Walnut oil product.
Oil Curing Time:
Tung oil takes an incredibly long time to cure. Out of all of the different natural oil finishes and blends, Tung oil is easily the slowest-dryer of them all.
When it comes to polymerized Pure Tung oil, this stuff will take just 1 or 2 days to dry. However, it will take much, much longer to cure.
Don’t be surprised if you find yourself waiting 4+ weeks for a Tung oil top coat to fully harden.
Heat treated Walnut oil also takes 1-2 days to dry. But, it will cure in half the time of Tung oil, needing only a further 2 weeks to cure.
Related Post: Tung Oil Not Drying? (3 Simple Ways To Fix It)
To Sum Up, Here Are Your 3 Main Takeaways…
- 1). Do not use unrefined or unfiltered Walnut oil on wood. It will go rancid.
- 2). Only ever use a heat treated and filtered Walnut oil as a wood finish.
- 3). A Tung oil finish requires fewer coats than heat treated Walnut oil. However, Tung oil takes twice as long to cure.
References:
The performance of biodegradable Tung oil coatings – ScienceDirect
