If you want to give your wood project a coat of water-proof protection, then a tung oil finish is a great choice.
This popular finish is a non-toxic water-resistant oil that has been used by woodworkers as far back as the 10th Century.
Once applied, even just a thin coat of tung oil will harden into a durable shield of protection. And that shielding is what will keep your wood craft from falling prey to water, damp, and everyday wear & tear.
Still, knowing all of this is little comfort if you’ve found yourself scratching your head over a problem called ‘sticky tung oil’.
It’s likely been days since you’ve applied that last oil finish coat. And yet it still feels all tacky and gummed up. So why is that tung oil finish not drying?
If your tung oil finished surface is not drying, then it is typically down to one of two reasons;
- Over Application of Oil: After applying this finish to a wooden surface, (and letting it sit on the surface a short while), you need to properly wipe away any excess oil.
- Cold or Humid Weather: Tung oil dries faster in warm dry weather. This is because humidity and damp make it difficult for tung oil to dry and cure.
So now that you know some possible reasons why that tung oil isn’t drying properly, what can we do to fix it? Well, keep reading to learn more…
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How Long Does Tung Oil Take To Dry?
Pure tung oil, (with no extra added dryers mixed into it), will take around 24 hours to dry in-between coats.
But it will take a further 3 days, (totaling 4 days altogether) for it to completely cure.
Now, just to clarify, a Dry Oil Finish and a Cured Oil Finish are two very different things.
Drying refers to the oil evaporating from a liquid into a solid film coat. However, Curing is a chemical process that turns a liquid into a hard resistant resin.
Drying is a relatively quick process, that can be sped up by placing the tung oil covered work piece in a warm low-humid area.
However, curing is a process that takes as long as it takes. In other words, you can’t really speed up the curing process. Although humidity, cold, (and even a simple lack of air movement), can slow this process down.
How Long Does It Take For A Minwax Tung Oil Finish To Dry? Minwax Tung Oil is a product that mixes pure tung oil with varnish. That varnish additive means that Minwax Tung Oil can dry much faster than pure Tung Oil alone, needing only 5 to 10 minutes of drying time between coats.
So, How Do You Fix Sticky Tung Oil?
If it has been over 5 days, yet that tung oil still feels sticky, then it’s time to go back to the drawing board. You have 3 options here;
1. Remove The Tung Oil Using Mineral Spirits
This option is best used when the tung oil is still sticky, and no sections of the finish are dry.
A clean cotton cloth dampened in a quality mineral spirit is all you need.
Run the dampened cloth over the surface, making sure that you cover every part of the wood with mineral spirit solution.
The mineral spirit will thin out the tung oil, making it easy for you to wipe the oil off the work piece.
2. Strip The Tung Oil Using Paint Thinner
This option is more for when the tung oil has dried unevenly. In other words, there are surface sections that are forever sticky, yet other parts that have dried solid.
With this method you will be applying a turpentine or xylene paint thinner solution to the tung oil finish.
The paint thinner will soften the tung oil enough for you to be able to scrape it off with fine steel wool. Try to get back down to the bare natural wood underneath as best you can.
Afterward, you can reapply a new coat of tung oil.
3. Restore The Tung Oil Finish Using Wood Restorer
This option is once again best used on unevenly dried finishes. But it is a much less harsh approach than using paint thinner.
This method involves applying a wood restorer to the finish.
Using fine steel wool, you rub the wood restorer solution onto the oil finish. The wood restorer will penetrate the tung oil finish and improve the shine of the finish by blending away those gummy blemishes. And the steel wool will help to get rid of the stickiness.
Which Option Should You Choose?
It’s up to you really. However, out of the three options, I prefer the mineral spirits and the wood restorer approaches.
If you want to protect the natural wood underneath a finish, then paint stripper should always be a last-gasp option. Why? Well because when you scrap a finish off this way, you can end up damaging the wood.
Mineral spirits, on the other hand, do no harm to wood. And using a wood restorer is an incredibly simple wipe-on/wipe-off task that any woodworker – from beginner to pro – can easily do.
If you are going to use a wood restorer, then a quality wood restorer such as ‘Howard’s Restor-A-Finish’, is a great choice.
Howard’s Restor-A-Finish is available in a range of different natural timber colors. So be sure to get it in a color that best matches the hue of your work piece.
And for a visual guide to using wood restorer to remove a sticky oil finish, check out Todd Languell’s quick and simple video tutorial below:
The centuries old woodworking problem of an oil coat not drying doesn’t have to mean the ruinous end of your woodwork project. If that tung oil finish isn’t drying then you always have a few options available to you;
- Have you given it enough time to dry? It takes up to 24 hours for Tung oil to dry, and 4 days for it to harden and cure.
- Is it still sticky after 5 days? Remove the finish using mineral spirits. Or try restoring the Tung oil finish by using a quality wood restorer product.
- When wood restorer doesn’t solve the problem? Remove the Tung oil finish using paint thinner, and then reapply a fresh coat.
Ebrey, Walthall, and Palais (2006), 133.
McKeon, Thomas; Hayes, Douglas; Hildebrand, David; Weselake, Randall (2016). Industrial Oil Crops. AOCS Press (published March 8, 2016). p. 243.