Tung Oil - Am I doing anything daft?

[Rattie]

I've just recently used tung oil to finish a piece of oak (planed and sanded to 180 grit). After a single coat (wiped off excess as instructed) three days ago the grain looks lovely, and the finish is just as we wanted, a nice semi matte rather than a gloss. However there is still obviously some undried oil in the board, which becomes obvious when handling it, as capillary action brings it to the surface where your hand has been.

Is this normal?

Should we have done more after the first coat to help drying?

How long would one expect this to take to dry if at all?

I assume that a gentle buff and another application is recommended, followed by more drying time, before finally applying wax - I was intending to use Briwax or Black Bison.

I'm a little unsure of what to expect with tung oil on oak, the only oil I've used before was teak oil which didn't seem to behave like this, at least not on teak anyway.

Just hoping for a sanity check really,

cheers

Martyn

 

[Chris Knight]

Martyn,

Pure Tung oil does that - which is one of the reasons it is not used much. All the so called Danish and Teak oils have some form of drier (metallic salts usually, often called "Japan Drier") in them - as does "Boiled" Linseed oil which is not boiled at all these days but has a drier in it to stop the kind of behaviour you have just experienced and which is similar to using "Raw Linseed oil"

You can buy a drier from a specialist finishing supplies house to speed up the Tung oil, you can put up with that behaviour and wipe it off every now and then for about a week or you can use something else.

Pure Tung oil has no real advantage over alternative finishes for most things and there is not much point in using it in my opinion. For oak and an oil finish I would go with Liberon finishing oil which is very easy to use, dries quickly and reasonably clear too.

You can test all these things yourself very easily. Get a clean piece of glass and then pour on a small amount of oil (about a half a cubic cm or so) so that it forms a small puddle. use a wax pencil to write the time of pouring. Do this with all the oils you want to test. Check at 15 minute intervals for the next few hours and note when the oil polymerises and how it looks. You will be surprised just how yellow and yukky some oils look - also how long some take to dry - test them with a fingernail (they will all scratch, some more easily than others). You will give up checking on Tung and raw linseed at bedtime and they will still be soft the next day. Others will set in an hour or two.

 

[Alf]

I had cause to pass the time with a wage-earning finisher a couple of years ago, and he was very enthusiastic about Tung Oil. He readily acknowledged it wasn't option in his paid work because of the long drying time, but for home use he gave it the highest recommendation. Claimed he'd finished a chopping board with it about 10 years previously and it was still as good as ever. Despite the well-known Cornishman's ability to spin a yarn, :wink: it seemed a genuine recommendation. As a gauge of whether he knew what he was talking about, the workshop he worked in had just finished a batch of four poster beads for Harrods. Okay, so they were for dogs, but you know how fussy pet owners can be, especially insanely rich ones... :roll:

Cheers, Alf

 

[Rattie]

Chris,

Thanks for the advice, it does make alot of sense. With Liberon's Finishing Oil being tung based I guess it would be OK to use that for subsequent coats. Is that a safe assumption?

On a different oily note, I got round to ordering a couple of bottles of Gilly Stephenson's Orange Oil today from Good Timber. It'll be interesting to try your glass test with that too. Should smell nice at least

Alf, Interesting to here about the tung recommendation for when time is less of the essence. This piece is a simple jointed laptop rest for a mate, who doesn't want his lovely new vaio to overheat, so we'd better get it sorted pronto :wink:

Cheers

Martyn

 

[DaveL]

This piece is a simple jointed laptop rest for a mate, who doesn't want his lovely new vaio to overheat,

I don't how hot the vaio runs but the laptops I have used become uncomfortably hot on the lap if used for very long. So this project sounds like a good idea. Please let us know how it works out. 8)

 

[Chris Knight]

I guess it would be OK to use that for subsequent coats. Is that a safe assumption?

Martyn,
It should be fine as long as the Tung has properly "gone-off" i.e. polymerised. However, don't be in a hurry to do it - leave it as long as you can. It is possible that the driers in the Liberon would speed things up with the Tung but this is an educated guess, not certainty and the safest course is to leave it to dry by itself.

Liberon recommend five hours between coats and I would stick with that even though the suface may feel dry sooner. As with any oil, and as Liberon's instructions will say, you need to rub off the excess before it dries. If you do feel a rough suface, just smooth with 320 grit sandpaper before the next coat.

 

[Rattie]

Cheers,

I'll leave it until the weekend then. That'll give it an extra long drying time, and is probably the easiest time to get the new oil.

I'll post a couple of pics when it's done. It's hardly an advanced project, but as DaveL says, it'll come in really handy in use.

Martyn

 

[PitBull]

Martin,

I really like Liberon Pure Tung Oil (PTO) for a lot of furniture, but for some things it is just too soft.

I used it for an Oak-based Kitchen spice rack for glass jars, and the finish scratched up somewhat on the shelves where the jars were sliding across them. I re-did this with Liberon Finishing Oil and had no more scratches.

I generally did two coats of PTO or FO per day - one first thing in the morning, one last thing at night. Make sure you really do take off all the excess, and cut back with finest grit webrax or similar every few coats.

 

[Anonymous]

Martyn

I use Tung oil a lot and pretty much agee with what has been said here. I find one coat a day is safe and have no problems with cpillary action when I observe this rule.

I think that Tung oil gives a nicer finish than other oils I have tried.

 

[Rattie]

ahh,

so I guess the reason for the effect I'm seeing is that I haven't cut it back after the first application. I'm guessing that'll mean there's no fine oak dust to soak up the "internal excess".

In that case, I'll follow your methods and keep going with the PTO for this piece.

Cheers
Martyn

Oh, my orange oil came this morning, will try that on my next piece I think.