Tung Oil Disaster - continue or start over?

[m4rk0]

I must be doing something wrong here..
after 3 coats of grain filler, 3 coats of pure tung oil/thinner mixture and about 5-6 coats of Tung oil, the finish is still patchy and uneven..
it almost seems as if it is drying/building differently on certain colored parts of the rosewood grain - See pictures

so this is what I did:
3 coats of Tung-oil/Thinner Mixture:
wiped it on fairly thick, wiped off as much as possible after about 10 minutes.. came back later to wipe more..
during these coats, not much stuck to the body, especially the rosewood top..
drying 3-4 days between coats

5 or 6 coats of pure Oil:
initially wiped it on as thinly as possible, and wiped off as much as i could after 10 minutes.
again, not much seems to stuck to the top, while the korina back seems to absorb most of the oil straight away.. not much build-up on either side
drying 3-4 days between coats

on the 4th coat I decided (as per some advise on some random furniture finishing sites) to apply as thinly as possible and NOT wipe off at all..\
On the darker parts of the rosewood grain, some finish is building, while on other parts it almost seems to bleach the wood..

on the 5th and 6th coat, I wiped on thinly and wiped off lightly..
for the last 3 coats, I waited about 6-7 days (and I am running out of patience  :tard

it still looks crap and I am not sure if I should:
- continue and hope it will build up more and more evenly
- sand off and start again
- sand off and finish with Tru-oil instead

so I am not sure if Tung oil is a good match with Rosewood.. it is quartersawn rosewood, so I am not sure if that makes a difference too

here are some pics. It is most visible in the non-flash pics:

 

[m4rk0]

oh another thing I am pissed-off about:

When I filed the grain (with clear waterbased filler from stewmac) I sanded with 220 and 320 between coats and finally with 320 and up..
by the time I was done it was supersmooth!

after some coats of tung oil, I can see sanding scratches at the bottom of the body where the grain curves, only from a certain angle in a certain light..but still pissed off about it  :sad1:

what the hell did I do wrong? you can see it a little on the 4th pic from the top.

 

[Soloshchenko]

The problem may lie in the "wiped it on fairly thick" part. You should apply very thin even coats. What you seem to be getting here is patchs that aren't soaking into the grain of the wood as quickly and simply sitting on top of the grain/kind of oozing out of the grain.

Q: After wiping it down till its even and leaving it for an hour does the oil start "Seeping out" in small patches? If so, thew problem is almost certainly too much oil too quickly.

 

[jackthehack]

Nice Thinline! My closest experience is with a rosewood laminate top on a mahogany Strat body. The issue with Rosewood is that it is very oily and will not absorb much of anything, and trying to fill it's grain is a bitch.

I tried a number of finishing experiments on sections of that body and ran into some similar issues; I wound up sanding it back bare and going a completely "natural" wood look by hand rubbing 25-30 coats of WATCO Danish Oil to it. Not a glossy finish, but the color/grain of the Indian rosewood matched the neck's fretboard so it came out looking pretty good:

 

[TroubledTreble]

I think the different parts of the rosewood will absorb and dry differently due to how much wood oil is contained in each.

Have you tried applying in a french polish method? It should leave the surface quite smooth. They will be very thin coats but the end results will probably be more satisfying and take about the same time overall.

It sure is a beautiful project! I will enjoy watching the progress.

 

[m4rk0]

Thanks for all the advise so far!

Solo, I only wiped on thick for the first 3 coats, which were cut with thinner (50:50)
I had some seeping during those, but not with the pure coats.

Jack, TT,
Yes, it definetely feels like the natural oils react differently with the Tung oil.
and yes, it was a bitch to fill.  3 coats of filler didn't really do the trick all the way, but the tung oil seemed to have filled the remaining pores.

I have some good news though.. I just rubbed the whole body out with some fine steelwool, and it looks much much better now! I have applied a new coat in the meantime and wiped as much off as possible again.. looks like it still may work out.
if not, I will go for the danish oil or french polish method!

final Q, how many coats of Tung oil are usually requiered before you get to see an actual coat over the wood?

 

[jackthehack]

"how many coats of Tung oil are usually requiered before you get to see an actual coat over the wood?"

AFAIK, no set number, and can depend on how thick the coats you are applying and the underlying wood and prep. On my "KorinaCaster" the Flame Maple neck started showing a reflective coat after 2-3 coats. Korina body took a lot more, don't remember exactly.

Another item you didn't mention was how long you waited between coats; if you try to apply the next coat before the last one is completely dry you can run into a lot of issues. Tung Oil usually isn't really completely dry for a while after it first feels that way to your finger.

 

[m4rk0]

I waited anywhere between 3 to 7 days between coats, depending on if I used Thinner or how much oil I wiped off after applying it...
also have the fan on 24/7

ok, so it makes sense that Korina takes a lot more coats.. it seems to absorb a lot of it!

 

[ByteFrenzy]

"how many coats of Tung oil are usually requiered before you get to see an actual coat over the wood?"

Yes, it depends very much on the wood. With maple, almost immediately. Alder by comparison absorbs incredible amounts of oil for an enormous number of coats, even more so on the end of the grain (bottom of the body where the strap lock would go, underneath the neck socket, tip of the horns). Something you might want to consider is switching to Tru-Oil when you run into the first coat of Tung Oil that won't dry uniformly anymore. I was initially not very inclined to use Tru-Oil at all, but after finishing a couple of bodies and necks this way I feel this is actually a way to combine the best of two worlds, first Tung Oil or Linseed oil to give a deep penetration, complemented by a sealing layer of Tru-Oil.

 

[-CB-]

Tung like a thinned down and heavy first coat, then pure and very light coats after that.

Not to worry though.... just let the guitar sit a week or so , maybe 10 days.  Tung oil takes forever to dry.  You think its dry, its not.  Just let it sit.

Then keep going.  If you want, lightly sand those marks out that you found, and just keep going with light coats - letting it fully dry at least a week or more...  If you do this, it will turn out just fine. 

The problem you're seein is... its only part finished!