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Tung oil on desk

9.3K views 11 replies 7 participants last post by  Quickstep  
#1 ·
Hi all,

I just finished the top of a Walnut desk that my kid needs to school from home in the wake of COVID-19. Always wanted to use pure Tung oil on Walnut, so I put a coat on and THEN did my homework. Sadly, we don't have days and weeks to let 3+ coats dry. Any recommendations? I must say, it looks amazing wet.
 
#2 · (Edited)
A hard finish like lacquer with a 5 to 10 minute drying time and a one day till putting it in service time, to me is always a plus.
Your finish looks amazing when wet, not so amazing when dry.
What to do now? Try to remove as much as you can with lacquer thinner or other strong solvent. Then let dry for several days and try using a hard finish like lacquer, poly or in an emergency, use Shellac.
Shellac is somewhat durable but gives a beautiful finish.
 
#4 ·
My biggest reason for NOT using Tung oil is the smell, and it takes months to be completely gone. Oil based poly stinks pretty bad, but the smell is completely gone in about a week.
Water based poly has even less smell, but I don't like the bluish tint that I've gotten when using it. Clear lacquer dries very quickly and the solvent smell is gone in about 2 days. I choose my finish based on where it's going and how soon it needs to be put into use.

Charley
 
#5 ·
Don't know what lacquer you used, but it usually doesnt have any odor after a few hours. I have sprayed lacquer and delivered it the next day. I have always had box trucks and the floors were carpeted. When moving a good size table to location, I would just spread a blanket on the carpet, lay the table face down on the blanket and unload at location. I would just tell the customer not to put it in heavy service for about a week but OK to use right away for casual service. No odor at all.
The OP's problem is that even after removing the Tung with a strong solvent, there will probably still be some tung oil residue that would require another few days before it can be re-coated with lacquer, pre cat or not. Lacquer dries and can be re-coated in 5 minutes. The problem is not with the lacquer, it's with the tung oil residue. If you rush the process, you might get a lacquer finish that would be soft for a very long time. Then again, maybe not, but it sure is a gamble. If rushed, you will have a mighty big mess.
If at all possible, you might get in touch with a refinishing shop They will be able to strip it and wash it down and you will be able to finish it the nest day.
 
#7 ·
How about using a shellac sealer after "removing" the tung oil and before applying the lacquer? Something like Zinsser SealCoat? The woodworking stores recommend it around here when you use an oil-based stain followed by a water-based polyurethane finish, for example.

(Wipe-on oil-based poly finishes are gone from most woodworking stores around here, due to environmental regulations.)
 
#8 ·
Not sure since I never use shellac, but wouldn't the lacquer melt the shellac sealer and wrinkle it up?
Interesting solution if it works. If I had a shop right now, I would try it out of curiosity. Sure would be nice to know for future projects.
 
#10 ·
In my case, the "damage" is done - it looks good, but is STILL drying 3 days later. I think I went a little heavy on the application, so today, I wiped some off that still looked a tiny bit pooled and moved the piece into a covered outdoor area so the wind could blow across it. It's warm and dry here today, and is still looking the same as it did this morning, 9 hours later. I'm now thinking that I should have wiped off all of the excess the first day. Knotty areas of the wood soaked the oil up much faster, and are pretty dry already.



Lesson learned. If I had to do this again, I'd definitely go with a non-pure Tung oil (something diluted with solvent) for the initial application, at least. For something that needs to be food-safe, like a cutting board, I'd still go pure, but leave myself plenty of time, on the scale of weeks, to finish it completely.


All in all, if I had read this first, I might be in a better place right now.


Hope you're learning from my mistakes, intrepid searcher!
 
#11 ·
You’re right that you should have wiped off the excess initially, but I think you may be able to get the excess off by wiping it down with naphtha. The naphtha will hopefully remove the excess and let the rest dry.

Give it a day to dry, then a coat Or two of de-waxed shellac like Zinaser Seal Coat (it must be de-waxed). The shellac isn’t as durable, but it’s probably durable enough to get you started. Use a blotter or heavy craft paper to protect the surface until you have more time. Then lightly sand the shellac and coat over it with anything you want.

A couple of safety considerations.

If you’re using rags with the tung oil, make sure you dispose of them properly. They can combust spontaneously.

Naphtha is more flammable than regular mineral spirits so use it in a well ventilated area with no pilot lights on or anything like that.
 
#12 ·
Tony B,

You’d think that lacquer would make the shellac wrinkle, but it doesn’t. It’s very common for guitar makers to shoot a coat of de-waxed shellac to seal problem woods like rosewood and then topcoat with nitro.

I recently made a piece out of blood wood and to make it even redder, I shot a couple of coats of shellac tinted red and then top coated with lacquer.