I made my first project and finished it with tung oil as follows:
Finish sand to 220, clean with chip brush and tack rag
First coat 50/50 tung oil to mineral spirits- wipe dry
let cure 48 hours
2nd coat 50/50...wipe dry...72 hour cure
3rd coat 100% pure tung oil.
Wipe dry, wipe next day, wipe next day
6 day cure in garage 85 daytime temp..70 night temp
Now after 7 days, it appears dry, matte finish, but...when i put my hand on
it for 4-5 seconds, oil appears where it was touched and oil is also on my
hand. All the stuff I read said a week curing would be sufficient. Also,
it smells like a month old bag of Lay's tater chips.
Is the slow dry normal?
Can I speed up the drying?
How long before it cures?
When will the smell go away?
Thanks for reading this far,
First mistake was putting on too much oil. Tung oil is a penetrating
finish; it doesn't build a film. There is no point to more than one
application because the subsequent applications have no place to go if the
first one was adequate.
I would try cleaning an inconspicuous place with mineral spirits; though I
frankly have no idea what will happen.
I've heard of that, but I've never heard of french polishing with tung
Sounds like the OP had been over-generous with the oil application.
Personally I use a commercial oil blend (tung + thinners + driers) for
the first couple of coats and don't switch to pure tung until I'm
building the finish - maybe another 4-6 coats. Sometimes I even thin
the first coat even further.
I'd try scrubbing this piece down with thinners ("mineral spirits",
pond-side) and reducing as much oil off the surface as possible. Then
give it a week, and re-coat, but _thinly_ this time.
If you're _really_ screwed, switch to a shellac-over-oil finish. But
this doesn't work if the undercoat is "oozingly" thick.
So what is it he's feeling on the surface, if not a tung oil film?
Advice, as in other recent threads, is to use a "tung oil finish" with
driers and/or varnish added to firm it faster, after wiping off the surface
film to get the dust it's collected out of the way. Either that or warm the
whole thing up to speed the cure. Wipe off what bleeds off when warming.
"Build a film" is a term of art that implies that at some point in the
foreseeable future it is going to be _dry_ film. If you ignore the drying
part you can claim that axle grease is a film-building finish--you can put
it on 6 inches thick but you're going to continue to have a board covered
with a mess of axle grease and not anything that anybody would call a
"finish" until Hell freezes over.
Reply to jclarke at ae tee tee global dot net
I _wouldn't_ try warmth or sunshine on it, in an attempt to "get it to
Tung oil doesn't cure worth a damn. Boiled oils cure, but even they
are slow about it. Raw tung oil though is just going to skin over
while the layer underneath sits there and doesn't even think about
curing, no matter what you do to it. Maybe gamma rays...
I think you've got to take some oil off that surface before you can
Precisely why I told him to wipe the sticky film from the surface in the
The process of oxidation and cross-linking is speeded up, as are most
reactions, by elevated temperatures. Also, there is, by default lower
humidity, which lets the lesser volatiles escape..
Coats were applied very sparingly, rubbed in with a terry cloth, then wiped
"dry", after 20 minutes each time. I didn't let a film remain. There seemed
to be "dry" spots after the first two coats- so it appeared there was not
adequate coverage the first two times. The last coat did seem a little
"filmish" though before wiping 20 minutes later.
I see a lot of messages on this board about using pure tung oil and for the
life of me I don't know why people are bothering with it. Pure Tung oil
never seems to dry. I would use the Minwax Tung Oil finish. In fact we have
been using the finish for all of our furniture for over 18 years with great
success. I realize that it is Tung Oil/Varnish mixture with a dryer, but
the fact is that it makes an excellent finish when applied correctly. It is
easy to apply, easy to maintain, and does not possess any of the bad
characteristics of most other finishes. You never have to worry about your
finish cracking, chipping, fading, discoloring, orange-peeling, or any of
the other nasty things that can happen to furniture. It is more water
resistant than other oil finishes, and builds a silky smooth satin finish
over the wood with a minimum amount of effort. Tung Oil never needs to be
stripped and refinished. If a finish ever becomes dull, you simply apply
And this is how we finish our cherry furniture.
The key to a great finish starts with sanding. Table tops are sanded using
a belt sander equipped with a sanding frame with 120 grit. We then switch
to a random orbital sander with 120 grit. Next we sand the top with 220
grit also on a random orbital. The third step is to buff the top. I take a
piece of paper towel and put it between the table top and the 220 random
orbital paper and let it rip. The paper towel will do a good job in buffing
the top until it finally rips apart and blows all over your workshop.
Next take some Minwax tung oil finish a pour some in a plastic bowl. Wad up
some paper towels (Bounty is good because it is soft) and apply a generous
amount to the top. Then take some clean paper towels and wipe it completely
off as if you did not mean to apply it to the surface in the first place.
Just when you think you have removed all the excess tung oil, take a clean
wad of paper towels and do it again, moving with the grain from one end of
the top and moving off the other end, like an airplane landing and taking
off again from the surface of the table top.
Allow the piece to dry for 24 hours. This WILL dry unlike the pure tung
oil. Lightly sand the surface with a piece of 600 grit paper. And re-apply
another thin coat of tung oil, allowing it to sit for a moment and then
wiping it off again as described above.
If you live in a fairly dry region of the country you can get away with
applying 2 coats a day. (Except after the first coat - let that dry 24
hours.) Here in New England where it is humid in the summer you can only get
away with one coat per day.
After 5 applications, you should have a silky-smooth finish.ready for wax.
It makes a great finish, without all the headaches of other finishes.
Makers of The Small Table Making software program
I've never had a problem with pure tung oil not curing. I have had
a problem with boiled linseed oil not curing and remaining slick
and waxy for months.
Others have reported they never have a problem with boiled linseed oil
but do with pure tung oil. I cannot explain these apparent contradictions
For any oil finish that does not harden properly I suggest wiping
the surface with turpentine or mineral spirtis to remove any residual
oil on the surface and then flooding the surface with mineral spirits
into which a small amout of Japan drier has been added. Then keep the
piece in a warm place with low humidity.
Oil finishes cure by an oxidation/polymerization process, which proceeds
faster at a higher temperature and is itself exothermic, hence the danger
of spontaneous combustion with all drying oils and oil finishes. Some
polymerization processes evolve water and can be inhibited by high
humidity, I don't know if that applies to tung oil.
Sure sounds like you did all the right things and yes it takes an oil
finish some time to cure completely.
You might be experiencing some bleeding of oil or possibly you have some
high humidity problems but those are just guesses of course.
If you have to get it out of the shop you can try wiping the surface
with mineral spirits then drying with a clean rag. something that may
have to be repeated.
There isn't much more I can think of that you can do now other then
doing a surface finish and sealing off the oil but then you'd spoil the
In the future you could try a Japan Dryer added to the oil to speed up
Oils dry because they are exposed to oxygen in the air. They harden,
more or less. The thicker the standing film of goo the slower the
oxygen diffuses through the goo into an area where it's needed to
cause more drying. If the goo (film overlay) is thick enough,
underlying oils will never fully cure.
A Tung oil "film" is not super-hard. There's a test for finish film
hardness called the pencil test. You know how pencils come in #1, #2,
etc? - those numbers are related to how hard the pencil lead is - the
higher the number the harder the pencil lead. The test: you try to
make a dent in a finish with increasingly harder pencil leads you
record the hardness number that first makes a gouge or dent.
I'm not saying a really hard film is good or bad, just presenting an
organized way to look at finish hardness.
Tung oil that has cured for 30 days has a pencil hardness of 1.0+, NC
lacquer is about 3.5 or 4.0
In practical terms. a thick layer of tung oil, assuming you could
fully cure one, would make a fairly soft finish. I'm sure it wouldn't
be good as a writing surface, for example. However it would resist
bangs and other kinds of abuse better than NC lacquer would -
precisely because it has some give.
Next time you finish, don't use so much oil, 1 teaspoon / sq. ft is good
enough to color the wood and bring out it's natural beauty. Oil is a non
film building process, has little protection other than to seal the wood
If you want a quik finish that looks natural , and gives some
protection. Small amount of oil, I use a resin base oil, Watco usually,
wipe dry let dry usually 48 hours depending on drying conditions, then apply
either a Watco wipe-on poly, or reduce Straight Poly by 20-30% and apply
with a pad of cheese cloth folded into a ball, called a finishing Rubber.
Pour reduced Poly into pie pan and let rubber soak up contents and apply in
. Also, like a few of the others
said , take Mineral stirits and a scotch brite pad, white or lite green and
wipe surface , keeping it wet for a few mins. then wipe with a clean dry
cloth. You may have to do this process several times. The wood you used
is very porus and will soak up alot of oil.
Too Much Oil
Thanks for the info fellas.
I will let it sit for another week, then I will try the spirits + Japan
Drier. Thanks for the tip. BTW, there is no surface film, but my skin
wicks the oil out of the wood.
I might be wrong here, as Tung Oil always takes awhile to cure, but it seems
to me that some brands simply take much longer than others. While driers help,
some have still taken quite awhile. At this point, I've taken to adding some
shellac to the final coat of oil. That way the surface is fine in a few days
(or hours), and the rest can take a few months to cure without bothering me.
Same also holds for Linseed Oil. I also prefer this to using a varnish/oil,
and repair is easy.
(Above learned from rec.w abt. 8 yrs ago.)
On Sat, 03 Jul 2004 21:50:30 GMT, "K. B." < > wrote:
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