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I have researched and done everything to get my tung oil to dry . It was put on to thick first coat. I removed the coat and sanded . Used lacquer thinner to remove . Still not dry . Has been 10 days . Turned heat up to 75 in shop . It now was fairly dry but still slightly tacky . I used 50-50 lacquer thinner and tung oil . Wiped down and left it . Still tacky when checked after 18 hrs . What do I do ?

  • I think there are likely two issues here but it's impossible to be sure. The first I'm pretty sure of, too much oil was left on. The second is a guess, you may have a particularly slow-drying tung (it's a natural product so it can vary). The no. 1 thing to speed drying of oil finishes isn't a high temp, it's more oxygen. Any fans available to increase airflow? – Graphus supports Monica Jun 19 at 18:04
  • Aside from the problem you're having, tung oil is actually not a great internal finish. I think personally it's actually a dreadful choice for much of what it's used on. It's much more difficult to get a good-looking result using tun than other options, every one of which can be applied in exactly the same way and all of them dry more reliably. Plus its reputation for being water-resistant is exaggerated to the point that some express it as waterproof, which it isn't, not the way we use it on furniture. – Graphus supports Monica Jun 19 at 18:09
  • Thanks 🙏 I will think twice before trying tung oil again. I am going to lower the heat .I also put fans in . I am going to try UV lighting . I’m told it speeds up process.is there any product you recommend to go over tung oil when it dries. I have used epoxy resin in the past . – Ronald Vause Jun 20 at 23:14
  • I wouldn't use tung oil and then go over it with epoxy (the wait to be confident it was as well cured as I'd be comfortable with would be intolerably long). Wiping varnish on the other hand, there's no need for it to be fully cured. What this boils down to is I'd never use tung oil if I intended to use an epoxy topcoat. UV and heat do both help oil polymerisation, and the trad way to get those was to put stuff out in the sun, but the increased airflow is an invisible helping hand there so it wouldn't have been properly appreciated by many in the past how much that contributed. – Graphus supports Monica Jun 21 at 7:12
  • On the general concept of oiling first before another finish is used it's important to bear in mind that only some woods benefit from it and dark-stained softwoods may benefit much less than many unstained hardwoods for example. If tests had shown me I absolutely had to oil first to get the best optical effects from the wood v. straight epoxy I'd use BLO or a "Danish oil". And even with those (both touch-dry in hours, recoatable in 2 days max) I'd feel I had to wait at minimum 2 weeks and possibly a month — I've seen epoxy delams, it's not something I ever want to deal with on a new item. – Graphus supports Monica Jun 21 at 7:19
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The following are the major factors that universally affect an application of a drying oil not 'drying' properly:

  • Too much oil.
    Not too much being applied, too much left on the surface. It's common practice to flood the wood, sort of spreading a puddle around, sometimes leave oil sitting on the surface for perhaps half an hour, and then wipe away excess1. While I don't apply oil this way myself2 this amount of oil being applied is not a problem. It's the wiping away of excess that many fall down on. My mantra is that the wood should feel dry when you're done3.
  • Damp conditions, especially if coupled with lower temps.
    High humidity is the bane of oil finishes and always slows down drying and curing. And if it's particularly cold it can actually prevent proper curing of tung oil and other drying oils (and all finishes made from them which includes oil-based poly, "Danish oil" and similar blended products, and the majority of wiping varnishes).
  • Not enough air.
    Good airflow is vital to getting oils to dry as fast as they're supposed to, just a window cracked open can make a noticeable difference but if necessary a fan set up to blow air over the piece can be necessary4. BTW this is one reason that oil-based finishes were rarely used on the interiors of furniture pieces, because the oils could take an indefinitely long time to dry due to restricted access to air.

So bearing these in mind we easily see the key elements of proper oiling technique, to prevent a sticky/gummy surface, are to be careful to wipe away all excess, if possible not to use the finish if it's too damp and cold and to ensure free access to air.

Also as mentioned in a Comment above, oils like tung are a natural product and as such can, and do, vary from batch to batch (the colour differences alone can show us this clearly). So when using a pure oil in wood finishing the oil itself can vary more than one might expect. More than it should in an ideal world but they get what they get. Pure oils can't benefit from a little additional metallic driers being added to even out drying times the way that different batches of linseed oil can when they're making BLO. This is why BLO is as a rule more consistent in performance than raw linseed, tung or walnut oils, although it too can vary in colour.


1 Coming back periodically if needed to wipe away any more that has exuded from the wood and beaded on the surface. This is reasonably common with oak for example but can be seen in other species (usually at a smaller scale though because the pores as smaller).

2 It's too wasteful and there's absolutely no difference in effect to applying the oil more sparingly at each coat and rubbing it in well — everyone using oil should do a few comparisons for themselves to confirm, to help reduce waste of expensive oil finishes.

3 Not even remotely oily. If it feels oily (and not sort of smooth and waxy) there's oil still on the surface that needs to be removed.

4 Some might worry that this will lead to too many dust nibs but that's not a concern, remember you left the surface dry after application. You did, right?

  • I appreciate your responses. Very helpful. I dropped the gloves on this one and started over. I stripped tung oil off and re stained. I believe this was the best answer . I am applying a different top coat product. No more tung oil. Although I still like the product as I have finished several successful projects with tung oil. I will keep you posted as to the outcome . – Ronald Vause Jun 23 at 12:39

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