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I have made a small jewelry box from steamed black walnut for my significant other. My original idea was to sand it down to 400 grit and finish with just oil (which I did, with two coats of IKEA "Skydd" mineral oil), but I liked the high gloss so much I decided to give a try to lacquer... and things went downhill from there.

The first thin coat of lacquer was absorved almost entirely by the end grain. Also, the lacquer was taking days get dry enough to touch (an alkyd resin-based lacquer premixed with naphtha as solvent, supposed to dry fully in 24 hours). At this point, I sort of panicked and applied 4 more generous coats using a brush in quick succession, barely waiting 48 hours between coats.

Now it's been a full week since the last coat was applied and the lacquer is still rubbery to touch, nowhere near hard enough for sanding. I only have a week or so left before the event the box was made for and given the progress so far, I doubt it will fully dry (but then it's my first time with lacquer, so I don't know).

Any ideas how can I save this project? I'm OK with removing the lacquer with paint thinner, but I'm not sure if that will damage the wood. Also, where did I go wrong with the finishing?

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My guess is that the oil is acting as thinner that prevents the lacquer from catalyzing.

Shellac can be used as an intermediate layer between oil and lacquer (be sure to use dewaxed shellac)

At this point, you may be best off to just remove any finish and start over.

  • Thank you, I was afraid that this would be the response. Will paint thinner remove mineral oil as well? I may have enough time left to start again with spray-on acrylic lacquer (that should take only 2 hours per coat to dry), but I'm concered running into the same issue with the remaining oil that already penetrated the wood. – PeterK May 12 '15 at 19:07
  • @PeterK Your comment would be a good start of another question. Would help make the site better and get you and LeeG some more rep! – Matt May 12 '15 at 19:11
  • @Matt: You are right, of course, no further questions in comments on SO. For future reference, though, the thread at forums.finewoodworking.com/fwn-experts/john-white/… that confirms LeeG is right in all points: naphtha acts as a solvent for mineral oils (hence my problem) and shellac is the recommended intermediate layer even after stripping the lacquer, because some oil will remain in the wood. – PeterK May 12 '15 at 19:18
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    @PeterK Don't get me wrong... little questions and discussion are perfectly fine. It's just that question is not in the scope of your original. We are after all a beta site and can use all the excellent questions we can get. You could even answer your own new question with those points. – Matt May 12 '15 at 19:21
  • @Matt: No problem and I appreciate the explanation. Also, I'm new to this StackExchange community, but I've answered a few questions on SO and seen how questions can spiral out of control in comments (I see we share an interest in PowerShell, that is a magnet for this :), so I wholeheartedly agree. – PeterK May 12 '15 at 19:30

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