tung oil

[beaumontnz]

hi

I recently made a dining table out of recycled mahogany and oak,and was persuaded to finish the top with tung oil.
I noticed it had easily gotten scratched,so decided to lightly sand out the marks and re-oil it.
However,like the first time,once it had dried,it looked lovely in one direction,but dull when looked at in the other.I never buffed it on either occasion when it was dry,but now ,there is a nasty mark ,what looks like it was caused maybe by leaky batteries ,which i have had no other option but to sand back to bare timber to remove it.

Any one had much experience with tung oil?

Can i re oil this patch and blend it in,or do i have to sand the whole table back and start again?

Can /should i buff it if i re oil it?

Its a whole load of work to sand it back,but i dont think tung oil was the right choice ,maybe beeswax or briwax would have been better,or even satin varnish ,as i do not want a shiny finish.
Any advise would be appreciated.

 

[ironsidebod]

Did you mix the oil with white spirit for the first application? Tung is the right oil for oak no idea about mahogany though.

 

[beaumontnz]

yeah did all that.

could be the wood type like you say.

thanks

 

[Deleted member 174758]

Real mahogany, like oak, idigbo and walnut, contains tannin and that can react with water and iron to produce a blue/black staining. Is that the sort of problem you have? If so it can be removed by stripping back completely and treating the affected aea with oxallic acid. The top will then need to be restained and resealed with tung oil

 

[beaumontnz]

If you can maybe see the attached image, it will give you an idea of what's happened. It is very difficult to convey the dullness when seen from a certain angle,but reading another post on tung oil the other day, it could be I put too much on and didn't work it in enough.
There has been no black staining or anything like that.

 

[AronSearle]

Oxalic acid cleans iron staining (iron staining is the blue/black staining), tannin staining is more dark brown and happens because the tannins are water soluble and can deposit on the surface. I am not sure it is either of those.

Possible that you did not fully sand it, and the patchy appearance is caused by uneven penetration of the finish.

TBH the solution is the same anyway, sand it and start again.

Sanding and repairing that path is possible, but the timber may already have started to darken from fresh and so colour matching is difficult. It may be over time that any newly sanded and finished patch will also darken and blend in. I did the same on a table (too lazy to sand the whole thing) and it took 6 months for the new patches to colour change to a match.

If the whole thing is still fairly new, maybe that isn't an issue.