Thread: Tung oil

Hi sussertown

I'm guessing you mean that you used Tung Oil.
Do you know if it was pure Tung Oil, a polymerized tung oil, or a Tung and varnish blend (which is often labeled as Tung oil).

Also, did you thin the Tung Oil with mineral turpentine or a natural (pine or gum) turpentine.
And was every coat thinned, or just the initial coat?

My first guess is that the oil hadn't completely dried when you applied the floor wax, and excess oil bleeding o the surface is causing the "spotty" appearance.

I think the fix will require stripping the wax with a suitable solvent -- which one will depend on the formulation of the wax -- and then wiping the box down with additional turpentine. You may need to resand the box, but I'm not sure. The tung oil needs to be completely dry -- i.e. completely polymrised -- before you wax the box.


Some tips from Lee Valley's web site

How to Apply Tung Oil
Both forms of tung oil [pure and polymerised] are easy to apply. They are wipe-on, wipe-off finishes. Both penetrate well, sealing the pores of the wood. And both pure and polymerized tung oil build quite quickly. A sealer coat, plus one or two top coats, is usually all you need for a smooth and durable finish.

Pure Tung
For non-food contact use, always thin with 50% mineral spirits for the first coat. Subsequent coats can be full strength, but must be wiped down after 15 minutes. Always allow ample drying time (48 hours+).

Tung Oil Sealer
Sealer is 20% poly tung and 80% driers. It penetrates well and dries quickly.

High Luster Polymerized Tung Oil
Wipe on, then wipe off after five minutes. Gives a hard, tough finish with a hand-rubbed appearance.

Medium and Low Luster Finishes
For a medium luster finish, add one part Sealer to two parts High Luster. For a low luster finish, add two parts Sealer to one part High Luster.

I don't normally use pure Tung oil as a finish as my understanding is that it takes a very long time before it dries(weeks?). If it is mixed with driers(turpentine) it dries quicker, I am just not sure if this shortens the time for tung oil to fully cure.

You did not mention the time between the last coat of Tung oil and the wax?

Originally Posted by Christos

I don't normally use pure Tung oil as a finish as my understanding is that it takes a very long time before it dries(weeks?). If it is mixed with driers(turpentine) it dries quicker, I am just not sure if this shortens the time for tung oil to fully cure.

You did not mention the time between the last coat of Tung oil and the wax?

Hi christos
As far as I know, turpentine is a thinning agent for Tung Oil, it is NOT a drier or drying agent.

If you have pure Tung Oil, you can add Japan Dryer to it to speed up the polymerisation process, but I can't find any info on how much Japan Dryer to add to the Tung Oil.

Originally Posted by ian

Hi christos
As far as I know, turpentine is a thinning agent for Tung Oil, it is NOT a drier or drying agent......

Cool. Something that I was not aware of.

We used Terrabin as dryer in our pre Feast Watson fine buffing etc daze.
Gum turps also.
H.

Originally Posted by sussertown

I used cut tongue oil (TURPENTINE). I put 3 coats on a box. After it appeared to be dry I added floor wax and buffed. Looked beautiful. a few days later it looks spotty, uneven.

Perhaps this is your problem; each coat should be fully dried before doing the next... otherwise you've really only applied one coat. (Subsequent coats thin/remove the prior!) And the first coat invariably goes spotty as it's absorbed into the timber.

Pity you've already waxed, else you could treat what you have as the "first" coat and simply apply a second.

After all, you've nothing to lose except a bit of time & labour; you already need to redo it and if a second coat worked you'd know to wait longer next time.

I use pure tung oil all the time and love it but it does take a long time to dry especially if you are using it on tight grained or oily wood. For instance tung oil on maple or basswood would soak up and dry fairly quickly. Tung oil on Jatoba or Pau Ferro takes ages to dry.
This is why tung oil is usually mixed with other solvents.
One suggestion I have is to use a sanding sealer first. It will put a barrier between the wood and the finish. What's happening is your wood is sweating. It will bubble like that for a while but will most likely settle down and smooth out believe it or not. I've done this plenty of times.

The rustic furniture shop down my street introduced me to MinWax Tung Oil Protective Finish (aka TOPF).
There is some tung oil in it and lots of other things.
One coat is satin, darkens the wood a little. When you can't smell it, time for coat #2 and so on.
If you can feel any raised grain, do not sand it. That only shreds more wood.
Instead, use XXX coarse steel wool = the strands are flat, not round, not brittle, and cut like a million chisels.

Four coats is water-wet glossy on wood carvings. TOPF is a good finish on unpainted parts of wood carvings.

My guess is I didn't let the stain dry or the coats of oil. I subsequently did a lot of research and ended up using this as a spray gun and lacquer education. I finally learned how to use the gun and got a beautiful finish after several trials and errors.

See my reply to my own question.