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Raw/Pure Tung Oil finish - seeping issues

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Forum topic by LukeSommer posted 07-16-2017 01:16 PM 2055 views 0 times favorited 30 replies Add to Favorites Watch
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LukeSommer

10 posts in 8 days


07-16-2017 01:16 PM

Topic tags/keywords: tung oil finish finishing seeping weeping

Sorry if my first post offended anyone – EDIT:

I’ve used Raw/Pure Tung Oil (100% Pure Raw Tung Oil from Real Milk Paint company) many times with great results, but I’m finishing a table with Acacia/Rubberwood butcher-block type top and it seems that the large pores of the Acacia are giving me trouble. Would be interested in replies from anyone with experience finishing with Raw Tung Oil.

I followed the usual steps I always do: flooding with 50/50 Tung/Citrus Solvent for the first application, 75/25 for the 2nd, and about 85/15 or 90/10 for the third.

The second and third coats I also wet-sanded the oil in using 0000 Steel Wool and then wiped the sludge away thoroughly.

Between each coat, I wiped all excess oil off and waited for at least 4 days in between each. It took much longer to dry than I’ve ever experienced. But I know each coat was DRY (not of course CURED)—because between each, I sanded lightly with either 220 sandpaper or the Steel Wool, and the dust was a fine white powder – no gummy residue, indicating it was dry enough to add another coat.

(I live in FL, but I have the table inside where it is normally air-conditioned to 76 degrees, so the humidity is NOT high. To aid in the drying I turned the AC down to 72 so the air would be even drier.)

After each coat, I noticed that the oil was continually seeping out of the pores, so I was wiping it off about every 15-20 minutes for the first 8-12 hours, and then several times a day for the next 2-3 days. Again, I’ve never experienced this before, and I’m sure it has to do with the large pores of the Acacia.

Still, the first 2 coats went on fine and were completely dry before applying the next coat.

On the third application, I kept wiping and buffing as usual, and all was fine until the third morning when I checked it, oil had seeped out overnight and DRIED, so now there are dozens of tiny spots that are glossier than the rest of the table. They’re not white—just glossier than the rest of the table—and you can only see them if you look at the table close to eye level in certain light, but the table is not as smooth where the dried oil is.

In an attempt to fix, I tried sanding with 0000 Steel Wool and then wiping down with pure Citrus Solvent – and then it was like a dam broke, and oil was seeping out of the pores all over! I was able to wipe that away, but the previously dried spots are still there – the steel wool and Citrus Solvent didn’t touch them. Also, the Citrus Solvent seemed to dry out the rest of the table and make it duller.

On a small section of the table, I tried using a 3M white Final Finishing Pad and a bit of Tung to see if that would break up the dried spots, but that did nothing.

My plan was to do 1-2 more final coats, this time of 100% pure Tung – no Citrus Solvent. However, I don’t want to do that until I know the best way to proceed.

Should I wait for several weeks to make sure the oil IN the pores is fully cured, and then sand and do a coat of pure Tung Oil, wet-sanding in various steps from medium to fine, to try to get rid of the spots?

Or, if I wait for it to thoroughly dry, and sand, and then just apply the pure Tung, will the Tung eventually build up so the rest of the table is as glossy as the spots, so it won’t be noticed?

Or, if I wait for several weeks and apply Polymerized Tung—which has a glossier finish – will that bring the rest of the table to the level of gloss of the pores, making it uniform? I’ve never used Polymerized Tung before.

Any advice appreciated!


30 replies so far

View RichTaylor's profile

RichTaylor

1151 posts in 282 days


#1 posted 07-16-2017 02:51 PM


PLEASE: IF responding to this post, do NOT reply unless you know the difference between Raw/Pure/Unadulterated Tung Oil, Polymerized Tung Oil, and what is marketed as “Tung Oil Finish”—or tell me why Raw/Pure Tung Oil is bad, and other finished are better, or to sand everything off and use Poly or Varnish instead. I have used Raw/Pure Tung Oil (100% Pure Raw Tung Oil from Real Milk Paint company) MANY times with great success, and this is my first problem. I am mid-way through this project, and am only interested in replies from those with EXPERIENCE with Raw Tung Oil that address what I should do NOW to fix it.

That’s not a great intro, telling people not to reply unless they know what they are talking about. You’d be amazed what you can learn from the occasional random reply.

I have extensive experience with The Real Milk Paint brand tung oil and citrus solvent, but since it sounds like you’re the expert, I’m hesitant to reply. Best of luck figuring it out.

Any advice would be appreciated!

- LukeSommer

LOL. Any advice? Didn’t sound that way in your intro.

-- No matter how much you push the envelope, it'll still be stationery.

View CharlesNeil's profile

CharlesNeil

1920 posts in 3563 days


#2 posted 07-16-2017 03:07 PM

Interesting ..

In the military I learned a valuable lesson…..........You have to know when to rise up and when to lie down.

It’s nap time

View RichTaylor's profile

RichTaylor

1151 posts in 282 days


#3 posted 07-16-2017 03:26 PM

Well said, Charles. Hey, on a side note, I was re-reading some finishing articles in Woodworking Wisdom and Know-How from the Taunton Press, and realized you authored one of them. So, I was learning from you long before I discovered Lumberjocks. Who knew?

-- No matter how much you push the envelope, it'll still be stationery.

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LukeSommer

10 posts in 8 days


#4 posted 07-16-2017 05:36 PM


I have extensive experience with The Real Milk Paint brand tung oil and citrus solvent, but since it sounds like you re the expert, I m hesitant to reply. Best of luck figuring it out.

- RichTaylor

—RichTaylor—YOU are someone whose advice I’d really appreciate hearing. It’s just that I’ve read through so many forums where people ask questions like mine and get a hundred responses from people with no experience with Tung Oil saying “Raw Tung Oil sucks – sand it all off” or discuss how to use polymerized Tung Oils or “Tung Oil finishes” not understanding that those are completely different.

Thanks

View Carey  Mitchell's profile

Carey Mitchell

101 posts in 1652 days


#5 posted 07-16-2017 11:35 PM

I’m going to take a stab at this from the logic perspective; I could be wrong. I haven’t used tung in 30 years and I suspect the stuff back then was really tung.

I suspect the issue is the large pores of the acacia since you have not experienced this before and the rubberwood does not show the problem.. The larger the pores, the more oil is deposited in those pores, and the deeper the oil penetrates. My memory is that tung is one of the oils that cures by reactng with oxygen. More oil and deeper penetration would require far longer time to cure as the stuff below the surface is oxygen starved.

I had an antique mahogany bed that required forever for the tung to cure, and it oozed for days like yours.

View LukeSommer's profile

LukeSommer

10 posts in 8 days


#6 posted 07-16-2017 11:44 PM


I m going to take a stab at this from the logic perspective; I could be wrong. I haven t used tung in 30 years and I suspect the stuff back then was really tung.

I suspect the issue is the large pores of the acacia since you have not experienced this before and the rubberwood does not show the problem.. The larger the pores, the more oil is deposited in those pores, and the deeper the oil penetrates. My memory is that tung is one of the oils that cures by reactng with oxygen. More oil and deeper penetration would require far longer time to cure as the stuff below the surface is oxygen starved.

I had an antique mahogany bed that required forever for the tung to cure, and it oozed for days like yours.

- Carey Mitchell

Thanks, Carey. Sorry for the confusion – “Rubberwood” is another name for Acacia.
I suspect the same. Any thoughts on whether continuing at this point would build up the sheen to the point where the spots would blend in, or should I give it a few weeks for the pores to be fully cured and then wet-sand the oil in on the next coats?

View TungOil's profile

TungOil

391 posts in 188 days


#7 posted 07-17-2017 12:17 AM

You could try calling the Real Milk Paint company for advice. I’m sure they have a customer service department that might be able to help you.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View Carey  Mitchell's profile

Carey Mitchell

101 posts in 1652 days


#8 posted 07-17-2017 02:49 PM

Thanks, Carey. Sorry for the confusion – “Rubberwood” is another name for Acacia.
I suspect the same. Any thoughts on whether continuing at this point would build up the sheen to the point where the spots would blend in, or should I give it a few weeks for the pores to be fully cured and then wet-sand the oil in on the next coats?

I would give it a few weeks. Raising the temperature would help, but don’t be surprised if the rate of weeping increases a bit.

View Kelly's profile

Kelly

1653 posts in 2637 days


#9 posted 07-17-2017 06:01 PM

Good thread. I used to buy my pure, polymerized tung oil for around thirty-four a gallon out of Winthrop, Washington. I loved the stuff. Though not an idea finish for things requiring durability, I test drove it on a 10-22 stock and, a few coats down the road, it was beautiful.

I’ve long been aware tung oil and BLO reacted with oxygen to cure (a few people used it to remove oxygen from stored items), rather than merely gas off the solvent. Never thought about the matter of deep penetration, by way of pours, being a problem, but I will consider this potential problem using it when that could be a problem.

I presume the problem would be merely reduced using polymerized and treated (metals) oil, but would still be a problem.

I have to wonder what would happen if you could place the item in a vacuum bag and pressurize it, like they do with hyperbaric chambers, rather than applying a vacuum. If the top layer of oil hasn’t fully cured, it seems the pressure might push the air, thus oxygen, into the wood.

If I went that route, I test on a sample, since air in wood is a pain, as you likely know, when trying to get a top coat on something.

Curious and confused – my brother gave me a dead tree from his back yard. He said it was acacia. When I cut, planed and sanded it, it reminded me of [beautiful] walnut, but more golden brown. When I run rubberwood and acacia, I get two completely different results. The acacia looks like what I got and described, but not so the rubberwood.

To make matters worse, a guy at our turning club brought an olive wood bowl, which looked like it could have passed for acacia. Running the two terms together produced results indicating there is acacia olive wood.

Any insight?

Thanks, Carey. Sorry for the confusion – “Rubberwood” is another name for Acacia.

- LukeSommer


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LukeSommer

10 posts in 8 days


#10 posted 07-17-2017 06:33 PM



Good thread. I used to buy my pure, polymerized tung oil for around thirty-four a gallon out of Winthrop, Washington. I loved the stuff. Though not an idea finish for things requiring durability, I test drove it on a 10-22 stock and, a few coats down the road, it was beautiful.

I ve long been aware tung oil and BLO reacted with oxygen to cure (a few people used it to remove oxygen from stored items), rather than merely gas off the solvent. Never thought about the matter of deep penetration, by way of pours, being a problem, but I will consider this potential problem using it when that could be a problem.

I presume the problem would be merely reduced using polymerized and treated (metals) oil, but would still be a problem.

I have to wonder what would happen if you could place the item in a vacuum bag and pressurize it, like they do with hyperbaric chambers, rather than applying a vacuum. If the top layer of oil hasn t fully cured, it seems the pressure might push the air, thus oxygen, into the wood.

If I went that route, I test on a sample, since air in wood is a pain, as you likely know, when trying to get a top coat on something.

Curious and confused – my brother gave me a dead tree from his back yard. He said it was acacia. When I cut, planed and sanded it, it reminded me of [beautiful] walnut, but more golden brown. When I run rubberwood and acacia, I get two completely different results. The acacia looks like what I got and described, but not so the rubberwood.

To make matters worse, a guy at our turning club brought an olive wood bowl, which looked like it could have passed for acacia. Running the two terms together produced results indicating there is acacia olive wood.

Any insight?

- Kelly

Thanks, Kelly, if I had a vacuum bag I’d try it! And you’re right – Rubberwood (which is what I have) is different from Acacia. I think the furniture maker used the terms interchangeably, which is where I got the false info. Rubberwood is also known as is also known as “Parawood” and it’s used today in a lot of imported furniture. I’ve bought several pieces because it’s an affordable way to get unfinished solid wood that you can then finish yourself. I finished a dresser made from Rubberwood with stain and varnish, and it turned out great. The pores didn’t seem to be an issuee with that one…

View LukeSommer's profile

LukeSommer

10 posts in 8 days


#11 posted 07-17-2017 06:41 PM



Thanks, Carey. Sorry for the confusion – “Rubberwood” is another name for Acacia.
I suspect the same. Any thoughts on whether continuing at this point would build up the sheen to the point where the spots would blend in, or should I give it a few weeks for the pores to be fully cured and then wet-sand the oil in on the next coats?

I would give it a few weeks. Raising the temperature would help, but don t be surprised if the rate of weeping increases a bit.

- Carey Mitchell

Sorry Carey – Rubberwood and Acacia are not the same after all. See Kelly’s comment below and my reply. The table I have is Rubberwood.

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LukeSommer

10 posts in 8 days


#12 posted 07-19-2017 08:31 PM

UPDATE: I sanded everything completely off. The spots disappear when I sand them off, but reappear within about 20 minutes. I then sand again, and each time there are fewer oil spots rising up. Now, they are almost entirely gone. Should I wait until they completely stop appearing after I sand? Would this mean they are finally dry?
Also: since the pores are obviously really deep, I’m wondering if I should perhaps just apply a very thin coat of 50/50 Tung Oil/Solvent (wipe on with a rag) instead of flooding the surface until it stops absorbing and then wiping, like I’ve always done in the past?
I’m concerned that if I use the usual method, the same thing will happen again (I don’t really understand why the oil keeps coming back up but it must have something to do with the extreme depth of the pores in the Rubberwood/Parawood)...

View ArtMann's profile

ArtMann

446 posts in 509 days


#13 posted 07-20-2017 03:33 AM

Your experience with 100% Tung oil is the same as the experience I had. I gave up.

View Kelly's profile

Kelly

1653 posts in 2637 days


#14 posted 07-20-2017 03:57 AM

Just curious, why raw tung oil rather than polymerized?

View LukeSommer's profile

LukeSommer

10 posts in 8 days


#15 posted 07-20-2017 04:03 AM



Just curious, why raw tung oil rather than polymerized?

- Kelly

That’s what I first started using and have had good results in the past. Do you think polymerized would be better for deep-pored wood? Is it similar to Raw in ease of refreshing (no stripping necessary – just sand lightly and re-apply?)

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