Tung Oil problems

[Rubingr]

I am using Tung Oil on a cedar rocking chair. After applying the 4th coat of oil, I found a thumb sized area that isn't taking the finish very well. Instead of begining to gloss over, it has a textured apearence.
I was thinking of sanding this are down a little with 300 grit sand paper, and continuing to apply the finish over it, but before I did, I would love some advice on it, since I don't have a lot of experience with tung oil.

[zitan]

Hi Rubingr;

Are you using pure tung oil, polymerised or a commercial secret mixture (e.g danish)?

For pure tung on softwoods it tends to take forever to build or at least cure properly. I can attest to this fact that when I didn't like how dark it made rimu (Dacrydium cupressinum), I planed it off and was amazed at how far it had penetrated. Made planing a breeze since it acted as a perfect lubricant. Ended up with a pile of oil soaked shavings on the floor, which makes for excellent kindling. My remedy was to shellac seal with some blond shellac (it was still thin enough it had a purple tinge in the jar). Then reapplied the oil, it set up much faster.

My other 'secret' is to finish outdoors in strong sunlight. A thin coat of pure tung will be completely dry in 30 minutes, and will be squeaky clean mirror glossy. I guess this is just the same as buying the more expensive polymerised stuff. The gloss slowly goes to gloss-satin over the next few weeks, in which case I'm assuming it's completely cured throughout. Using this, I can get a finished piece with just 3 coats of oil, steel-wool-ing in between.

My advice? lightly sand the affected area, put a thin coat of oil on and put a office lamp next to it to warm it till it's dry. You'll know it's dry when steel wooling or sanding produces white dust.
I wouldn't recommend putting the whole chair outside in the sun - I don't want to be liable for negligent advice!

zitan

[Rubingr]

Zitan,

Thanks,

The chair is eventually going to wind up outside anyway, so I don't think that will be a problem. I am using pure tung oil, and am about to go try just sanding it down a little before applying the next coat.

[soundman]

The problem you may be having is that the problem area may be more absorbent than others and holds more of the volitiles therfore takes longer to dry/cure.

giving it time may be worhiwhile.

if the previous application hasn't gone off & you add more you will in all likelyhood be starting the waiting time all over again.

I'd let it rest a few days & try again.

cheers

[DonLoretto]

Try sanding the oil into the spot with wet/dry 320 grit paper. Feather the area into the adjacent areas.