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Disappointing Tung Oil Results

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Forum topic by TheWoodenOyster posted 08-19-2014 01:59 AM 1758 views 2 times favorited 10 replies Add to Favorites Watch
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TheWoodenOyster

1275 posts in 1397 days


08-19-2014 01:59 AM

Topic tags/keywords: tung oil

Hey everyone,

I recently made a solid cherry desk for myself. I haven’t had a lot of chances to test out pure oil finishes, but since this project was just for the house, I figured if things went wrong, it wouldn’t really matter. I made the desk and smoothed with my #4 and touched up with 320. I decided to try a pure tung oil finish. I mixed the first coat of pure tung oil 50/50 with mineral spirits and generously wiped on, waited 15 minutes, and wiped off. Let dry for a day, then I did a second coat of about 75 oil /25 mineral spirits. Same process of wiping on and wiping off. All looked well at that point. I went out of town for a bit and came back 5 days later with some unpleasant results. Nothing was ruined by any means, but the grain was totally raised and I might as well not have sanded in the first place. If you are wondering, I did not raise the grain with water during the sanding process. Never have before and I have never had issues. The wood also took on a relatively ugly blotchiness. I have used oil based poly on cherry before and I think the blotching there looks just fine and actually adds to the character. For me, poly has always helped ribbon or curl really pop. This tung oil just sort of turned the irregular grain into fugly blotches.

Anyone else had the same results?

Should I just ditch pure oil finishes if I can get better results from poly?

-- The Wood Is Your Oyster


10 replies so far

View DocSavage45's profile

DocSavage45

7700 posts in 2304 days


#1 posted 08-19-2014 02:12 AM

Just a thought? Is it really tung oil or something else with tung oil? Reminds me of my refinishing fiasco. In testing out water borne poly I found definite brand differences.

Maybe rub it out to reduce the remaining tung oil? Let it dry. You didn’t mention the thickness of the cherry, maybe a scraper? To reduce the surface.

Hey even after I did test finish runs I screwed up. LOL!

Just thinking out loud.

-- Cau Haus Designs, Thomas J. Tieffenbacher

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Manitario

2397 posts in 2345 days


#2 posted 08-19-2014 03:50 AM

Minwax “tung oil” or real tung oil? Real tung oil needs 6-7 coats before it starts to look good, and generally more than 24h b/t each coat.

-- Sometimes the creative process requires foul language. -- Charles Neil

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TheWoodenOyster

1275 posts in 1397 days


#3 posted 08-19-2014 04:33 AM

It’s pure tung oil from Rockler. Dang 6-7 coats? That seems like overkill and a waste of time for “timeless” protection that won’t keep a water ring out…

-- The Wood Is Your Oyster

View wseand's profile

wseand

2754 posts in 2503 days


#4 posted 08-19-2014 07:31 AM

I have had the same problem, only with Oak. If the raised grain doesn’t settle down you probably just have to resand it and start over with the finish.
I have rarely used less then 5 coats of anything when finishing a project. If you are looking for a more durable finish you might try adding a poly to the mix. 1/3 of each or some combination.

-- Bill - "Freedom flies in your heart like an Eagle" Audie Murphy

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911Rob

1 post in 838 days


#5 posted 08-19-2014 09:15 AM

Even with pure tung oil you can get the blotchiness. Try cutting it down more, not less. When you have any type of swirls in the wood grain, especially any hardwoods the absorption rate and depth is going to vary and generally be much slower to absorb in those spots. Another thing I do is any spots that are tight grain, I raise with water first, allow to dry then apply finish (tung oil). I have even cut down tung oil 1/10 to ensure absorption into tight grain swirls. What will work for you is of course dependant on humidity, temperature, and so on. I still like tung oil finishes, but in any tight grain wood projects one of the things I have learned is thinner finishes will absorb better and more evenly.

View Billy E's profile

Billy E

162 posts in 1542 days


#6 posted 08-19-2014 11:47 AM

Lots of good comments, and let me also share mine. First, I have found that any finish I’ve tried has a possibility of raising grain. I just plan on sanding every coat or two. If it’s oil, it’s smoothing raised grain, if it’s a film-building product, then it’s smoothing dust nibs. As far as tung oil experience, I have done quite a bit of experimenting. Pure tung oil is too thick for me to easily buff off, so I cut it, like you did. My favorite thinner is orange oil (d-limonene) because it doesn’t have a strong smell and dries slowly. You can use whatever you want, but slow drying is easier, so avoid naphtha. Some woods really soak up oil. They will continue to soak up oil until all the pores eventually fill and are sealed off with cured tung oil. Tung oil by itself also takes a long time to cure. By itself (or with thinner, which evaporates and leaves pure tung oil behind) tung oil takes about 2 days to get thoroughly waxy. Even then, its soft. You can sand it at this point, but be prepared to use a lot of paper because it fouls quickly with the waxy half-cured tung oil. You would think I don’t like using pure tung oil and you’re right. Tung oil by itself is just too slow and soft for me to get real use out of. Now, I have had a great deal of success when I started blending in tung oil with any gloss varnish (not much difference in the brand or type). The advantage here is that it cures in less than a day, cures hard enough to sand easily, and more quickly fills the pores in the wood so by the 3rd coat you’re not really absorbing much even on end grain. The common mix of 1 part tung oil, 1 part varnish (poly is fine), and 1 part thinner works fine. I have tried experiments on both oak and walnut to see if varnish by itself looks different than varnish/tung and I can tell you there is a definite difference in how the grain is contrasted, or “popped”, when you start by adding tung oil to the mix. I believe BLO has a similar effect but that’s beyond the scope of this thread. You can start on your project now by blending in some varnish with your tung oil if you want. This mixture is not tough enough to use as a film on furniture. Once you get about 2-3 coats of the oil/varnish in the wood, you’ll want to go to your next coat which is either a varnish or wax.

-- Billy, Florence SC

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mahdee

3551 posts in 1229 days


#7 posted 08-19-2014 12:01 PM

Yep, had the same problem with Watco Teak oil.

-- earthartandfoods.com

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TheWoodenOyster

1275 posts in 1397 days


#8 posted 08-19-2014 08:40 PM

Thanks for all of the input guys. This is exactly what I was hoping for. Sounds to me like the pros of using pure oil finishes just don’t make up for all of the cons. I have been using straight wipe on poly up to this point, but after reading the responses, I might give a home-blended oil/varnish/thinner blend a try. Glad to hear it wasn’t just me. I am glad that I tried it out though, as I have been curious for a while now. Finishing is just one of those area where we all continue to learn all the time.

-- The Wood Is Your Oyster

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Billy E

162 posts in 1542 days


#9 posted 08-20-2014 10:00 PM

Please post your results. I’m interested to see how you resolve it.

-- Billy, Florence SC

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TheWoodenOyster

1275 posts in 1397 days


#10 posted 08-20-2014 11:31 PM

I resolved it by buffing with some steel wool to get some of the grain to sit back down. It’s not even close to as smooth as it was before the oil, but it is better that it was initially after the oil. I stopped at 2 coats. This piece is for the house and was more or less an experiment to try out some different construction and finishing techniques. I won’t be doing anything else to it.

-- The Wood Is Your Oyster

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