I used tung oil (the real stuff) on a wedding gift for a friend recently and had a weird thing happen with the finish. Here was the process I used 3 times
1) sanded to 320
2) mixed 1 part turpentine and 1 part tung oil
3) flooded the surface waited 10 minutes and rubbed out. I kept going back and rewiping for about an hour as some of the oil came back out of the surface.
4) waited 24 hours
5) repeat 3 times
The surface was silky smooth. I left it in my house for about 1 week in an well ventilated area — the surface was still very smooth I brought it to the office and left it there for a week. When I went to give it to him, the surface felt rough as if the finish had picked up a lot of dust. I brought it home and the lightly went over it with steel wool. The dust that came off was very powdery (i.e., the finish was dry) and I was able to smooth out the surface again.
There was a quite significant change in the humidity between my house and the office.
The surface is great now but I am hesitant to use tung oil again given what happened. Any thoughts or theories on what I did wrong or why the surface would change so dramatically?
Anna
Replies
Maybe it really was just dusty and needed to be wiped down with mineral spirits.
Tried that, the texture was embedded in the finish.
I don't know how it would have picked up that much dust if the surface was dry. It felt as though the oil came out of the surface and rehardened on the surface.
What kind of wood was this made from? Open-pore woods can bleed oils and oil based finishes for days sometimes.Jim"There are two spiritual dangers in not owning a farm. One is the danger of supposing that breakfast comes from the grocery, and the other is that heat comes from the furnace." - Aldo Leopold
It was a mixture of cherry and curly maple. Can it bleed for a week? Also do you think the sudden humdity change may have aggravated the bleed out?
Yes, it can bleed for weeks depending on how deep the oil penetrates and the moisture content of the wood.fwiw, next time do not flood a surface. Damp rag, well rubbed in. Keep at it until the surface doesn't show dry spots. Wait 24 hrs and repeat.Take care, Mike
Thanks. The reason why I was concerned is I am going to be using Waterlox (which I understand is Tung oil based) for my next project and was hoping to avoid the same problem.
Let me add that if you were using real, 100% pure tung oil, it will take weeks to fully dry. Pure tung oil is a very slow drying oil.As to Waterlox. Waterlox is a varnish pure and simple. All varnishes are made from a resin and a drying oil that is sort of cooked together to form a new compound called varnish. Thinners are then added to enable the product to be brushed or sprayed. Yes, the drying oil used in making Waterlox varnish is tung oil but once it has been combined with the resin, it is no longer tung oil. In other words, Waterlox varnish acts like varnish, not tung oil so the problems you are having with tung oil are not to be expected from Waterlox varnish.Howie.........
I am far from a tung oil expert but what has always worked for me was to wipe the tung oil on as thin as I could then in 4-5 minutes wipe off as much as I could with a clean cloth. Leave it set and in about 24 hours repeat.
GeorgeYou don't stop laughing because you grow old. You grow old because you stop laughing. - Michael Pritchard<!----><!----><!---->
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Tung oil does take a long time to dry. While I was learning how to use Tung oil (with the tried and true method of trial and error) I too had some very old white oak bleed an oil and varnish mixture after a generous application. I let the oil sit for days until I found it dried in a very spotty fashion. As I wipped it with a rag I decided it needed to be resanded. This worked very well in the second application as the oil and varnish mixture pentrated the wood and accepted the next few (more conservative ) applications very well. The finish has turned out to be one of the best finishes I have ever done, but it was lots of work. Now I am using raw Tung oil which takes about 7-14 days to dry (in my experience). What ever you do don't set the pieces in the direct sun light as this also tends to cause wood to bleed the finish then dry uneven.
Your last sentance is probably the best explaination. My office is very sunny and warm and it was sitting on my desk. Thanks. Won't make that mistake again.
Anna
As Howard said, Waterlox is a varnish finish and will not do what has happened with the tung oil "naked" use. Since the dust was embedded, my opinion is that your tung oil bled and caught the dust and then dried.Gretchen
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