help with tung oil on a guitar

At this point, my question would be “How does the finish look to you?” If it pretty much looks the way you want it to look, so far….so good.

Next, I think you have the wood pretty much saturated with the tung oil. It cannot absorb any more, which is why it is not drying. I’d take a clean rag and wipe it down as thoroughly as possible, then let it sit for a couple of days and see what happens. Once it dries out, I’d put a coat of paste wax on (good old Johnson’s is fine), just because I like the way it feels, and because it will add a little extra moisture protection.

-- Charlie M. "Woodworking - patience = firewood"

Hello Kieran, and welcome to Lj’s. Glad you could join in. Good place to be for all your woodworkin needs, and get excellent advice and help.
Now for your questions: I’ll try to help a little.
(1) You should never remove the original finish from an instrument that came from the factory. Even if it is a cheaper instrument as you stated. That’s a “no-no”, because you’ll loose 50-60 % of the value of the instrument if you ever decided to sell it. I have several vintage instruments(some as old as 50+ years), and they all have the original finish. Even if you decide to keep it, it won’t be original anymore.
(2) The finish that’s put on at the factory is a nitro-cellulose(a spray-on varnish, if you will), over the stain. Mine are all accoustic, and would kill the sound with the wrong finish on it. On electrics, the finish is there for looks and design mainly. All the sound is fed through the pickups and electronics.
(3) I would not have put tung oil on it, even cut 50 %. It needed a good spray varnish on it. Just my .002.
How long did you let the stain dry before applying tung oil? Sometines tung oil never drys good over certain finishes and feels sticky all the time. The more coats you put on the worse it gets, sometimes-not always, but some.
(4) If were mine(my opinion only), I would take it to a good luthier for a finish repair, or send it back to the factory and have it done over and right. Not trying to critisise,just stating what I would do. Good luck. Rick.

-- Remember--- one good turn-- gets most of the blanket!!!!

First of all, thanks for all the kind welcome emails—much appreciated!

And thanks for the replies to my questions. As for how the finish looks to me at this point, it’s definitely getting there. The last coat of oil looks pretty good—more uniform with a nice sheen and color emerging. Again I’ve seen lots of descriptions online suggesting 8 to 10 coats as a good rule of thumb and so far I have only four, but maybe the wood is saturated as Charlie suggests.

To Rick’s comments: this is most definitely not a vintage instrument nor a new instrument of any significant monetary value, even with the original finish. Its value, as far as I’m concerned, extends only as far as it is useful to me as both a project and an instrument to be played eventually (hopefully soon!). The whole idea was to experiment and learn, so I went in expecting that it would end up a modified instrument (and it’s going to have much better electronics in it than it came with when I’m finished). I chose tung oil after seeing lots of people using it (and seeming pleased with the results) on the Warmoth guitar forum, although of course it’s a matter of taste. As for the stain drying time, I waited nearly a full day after the second coat of stain before putting on the first coat of tung oil.

You said that the last coat of oil was not drying. Did the first three coats dry well? As Rick said, stain that wasn’t fully dry would cause the oil to be gummy, but that should have been obvious after the first coat.

-- Charlie M. "Woodworking - patience = firewood"

Looking back on my notes (I’ve been trying to keep a journal of everything I’ve done for tips and things to avoid in the future), it looks like I let the stain dry for more like a few hours than a full day. It was certainly dry to the touch when I applied the first coat of oil, but maybe that wasn’t enough. Previous coats of oil seemed not gummy but a little bit greasy, though not quite as much as this last one. I’ve been following what appeared to be fairly consistent suggestions online of letting it dry for 12-24 hours and then applying another coat, so I waited at least that long between each of the previous coats. But maybe not long enough.

Charlie, I took your earlier advice and wiped it down again this afternoon, and I’ll just let it hang out for a few days and look it over again to see where things stand. I still got some reddish tint on the cloth I used, which makes it seem like things aren’t getting properly sealed or the oil isn’t polymerizing. Maybe it just needs to sit for a week or so? I think I can muster the patience for that! :) Thanks again for your help.

Good plan.

Some close-grained woods do not soak up stain very well. I once stained some maple and top coated it with polyurethane the next day. Well…the stain wasn’t quite dry after all, and it took about a week for the whole mess to really dry.

-- Charlie M. "Woodworking - patience = firewood"

This does not really answer your question, but when I was building my one and only guitar, the true luthiers were pretty emphatic about using nitrocellulose lacquer for a finish. They claim in moves better with the instrument, sounds better, and wears well. It might still be possible to apply over the oil once it dries…check into it before hand if you decide to go that route.

I think your problem comes from a usual confusion between Tung oil and Pure Tung oil.
I use solely Pure Tung oil, ond from your description it seems that thats what you have as well. The cheaper Tung oild have undergone a process of polymerization and have some additives that speeds up drying.
Pure tung oil cures slowly. Very slowly. I usually wait 1-2 days between coats, and most of the time give the first coat 5 days to dry. I let the last coat dry for at least 2 weeks. I found that it truly cures only after 5 weeks. Your mileage may vary…

It is very important to wipe tung oil and not to leave any wet areas – they will become a problem later.
I think Tung oil will give you the sheen you are looking for without much sanding or using steel wool between coats. if you are looking for high sheen, wet sand the last coats with 400-2000 grit wet and dry sandpaper.

when properly cured and applied, Tung oil finish is second to none. it will be hard wearing, will look good for a long time and will resist almost anything from moisture to acids.

-- The woods are lovely, dark and deep, but I have promises to keep...

Which brand of tung oil are you using?

-- Randy, Rustic Artisan, a family tradition. (No PM's - auto-deleted.) - "I am a seeker, not a follower."

I’m using Woodcraft tung oil and have been cutting it with mineral spirits (I’ve since seen things online about folks using citrus-based thinners, which I think I’ll try next time). I’ve been wiping it down about 20 minutes after I apply the oil/thinner mix, and checking on in periodically during the couple of days I’ve let each coat dry to look for any emergent wet areas. After Charlie’s last post, I let it dry for a full two weeks before doing anything, then I applied another coat this past Saturday and another yesterday. I figured I’d do a couple more this way, then one final coat of 50/50 oil and thinner (or maybe no thinner?) and let it sit for about six weeks. With each coat it does seem to be getting more uniform, but even with these latest coats, some areas seem to dry much more quickly than others. Oddly, the parts that start to look less shiny right after I put a coat on are the places that feel most greasy for the longest. It is probably a combination of not-so-great surface preparation, grain filling, etc, but I’m new at this! :) Luckily the part of the body that seems to look the best and be the most uniform is the front, which is what will be seen most often, of course. The back has a mysterious splotch, and the bottom seems to be taking the longest to dry of any other part (maybe because I have it hanging up from the neck screw holes to dry?).

I have a feeling that part of the problem, too, is that this guitar had a finish on it that I removed to experiment, and I may not have sanded it down far enough in some places. But from what you’ve all been saying, it’s also a matter of just being patient and letting the oil properly cure. Much as I want to put it back together and play it (which I’ll do regardless of how it looks) I am trying to cultivate that patience. I’ll post some photos soon (including some before and after shots). Thanks again to everyone for your replies and advice!

If there was a finish on it prior to this, that may be part of the problem. Also if you don’t sand it properly the oil will absorb differently on the piece causing the oil to soak in more in places causing the blotchy look. Grain filling won’t help the oil dry faster.

-- Julian, Park Forest, IL

Have you considered polyurethane satin finish over the oil once it dries to give you a uniform, low lustre finish?

Stan, Long Island, NY

kdownes,
While I am by no means an expert on finishing, I have and do use tung oil quite often.I’ve heard you refer to a greasy feeling! Does it actually have a gummy or tacky feeling? Tung oil will often cure on the surface and not underneath. I apply tung oil first always, and usually mix it 50/50 tung oil/mineral spirits first coat, second coat is 3/1 tung oil and MS, third coat is pure tung oil and all subsequent coats are pure tung oil. Applying tung oil over sealers, will only prolong the drying and curing time for tung oil. I wait days after the first application and have waited a week or longer between subsequent coats for the oil to dry. I am using only oil and MS, and finally only oil. Karson, another LJ’er here has had success using Japan Drier in mixing his BLO and speeding drying time. While I hope that your applications of tung oil will eventually cure properly, I’m afraid that they may never cure. I hope I’m wrong. If the first coat of tung oil did not dry and cure properly, none of the subsequent coats will either. It sounds like from the fact that you are still seeing stain permeate through the wiping of subsequent coats that this is the problem. Again, I hope that I’m wrong. Please keep us apprised as to the final outcome of the finishing.

Sincerely,
Ken McGinnis

-- woodbutcher north carolina

Stan—I hadn’t considered that, but it’s a good idea. I have some Briwax I was going to put on over the oil finish once its dry, but I do like satin finishes, so maybe poly is the way to go. Any brand recommendations?

Ken—I have a sinking feeling you’re right. I just went down to the basement to check on the progress, and while parts of it appear to be drying OK, even the dry parts don’t seem completely dry. I can, for example, press a finger on the surface, and it leaves a noticeable print behind—I don’t know if this is normal or not. The parts I’m concerned about don’t feel gummy so much as greasy. I didn’t use a sealer, only a grain filler.

I decided to try an experiment this morning—I have a block of mahogany I got from Woodcraft that I was planning to stain the same color as the guitar and use to mount a small music box. I sanded down one side of it, applied the grain filler, and I’ll let that dry and sand it down, then stain, and try the tung oil. I’ll let that first coat sit for longer this time and see what, if anything, goes differently. If it does go differently, and I have a feeling it will… well, time to break out the sandpaper, I guess! It would be a bummer to start over but better that than a surface that will never cure properly, especially since the guitar will be rubbing up against my clothes a lot when I play it. Thanks for the tips and I’ll post again as my little experiment proceeds.

Ken,
I just very successfully covered 4 coats of Watco Tung Oil with 3 coats of Minwax Wipe On Polyurethane Satin Finish. It looks great and dried well.
I would wipe your surface down very well to remove any excess oil. Then I would buff it with a buffing pad if you have one, perhaps one that attaches to your drill.
Then I would wait a few days to allow whatever oil is left and exposed to cure.
Then sand lightly with 220 grit sand paper.
Apply 3 or 4 coats of poly until you have a uniform, non-blotchy finish.
LIGHTLY sand with 320 grit between coats.
You will love the finished product. I do on my coffee table.

Stan, let me make sure I’m understanding your procedure: you had a table that already had tung oil on it, and you covered that with the poly? Did you have trouble with the oil finish by itself? I guess I’m curious why you used both oil and poly—was it for the look of the oil and the protection of the poly? Folks on a guitar forum I visit have conflicting views on the look and durability of poly for guitars, but it looks like it might be a good choice. I’m learning what all these different finishes have to offer so I’d appreciate hearing more about your decision making process.

Another question is: if, as Ken suggested, those first coats never dried properly and I have to start over, does that mean sanding all the way back to bare wood, and redoing the grain filler as well? I figured I’d have to restain it if I’m sanding away at those uncured coats of oil, but the grain filler has been a bit confusing to use. I have Behlen Mahogany grain filler that I used before, which is pink and stays pink under the stain in spots (not my favorite look). I’m also curious if a grain filler is necessary with either an oil or poly finish. I don’t mind having open pores as long as that doesn’t invite damage that can’t be protected against by either the oil or the poly. I chose the mahogany grain filler on the advice of someone at Woodcraft to enhance the look of the grain—why a “mahogany” colored grain filler is pink is a mystery to me. I’m also uncertain I’m doing the application correctly—I have a Behlen squeegee and wiped across the surface of the body at about a 45 degree angle to the grain, then sanded it down after it dried—is this the correct procedure?

Kieran

kdownes,
I know that was not addressed to me-the last post-however I have a few suggestions. If you have to start over.Don’t sand at first-use pure mineral spirits to try and remove the old oil stain and wood filler. Once all is removed that you can-then sand if necessary.Once you have a new raw wood, clean surface try this. Mix 50/50 Tung oil and mineral spirits, use this as a lubricant to slurry sand the whole project with 220grit paper and allow to dry completely-should happen in 24-36hours-it will look very muddy and even have high spots on the surface-this is OK it will fill the pores correctly (color wise and wood wise) Then sand with 220 again to level and then your finish grit. Next reapply 50/50 mixture oil/MS allow it to dry throughly approx. 24hours. Mix Oil/ MS at 3oil/1MS-just add more oil to original mix apply and allow to dry-approx24hours. Now mix 3 equal parts 1/3 Tung Oil 1/3 Mineral spirits 1/3 Oil based Urethane varnish and apply-allow to dry-approx24hours. You will now have a really good look at a beautiful hand rubbed finish. rough up surface with 400grit and apply another coat of 3equal parts mixture-repeat this last step as many times as you like I usually do it about 3 times with the final coat needing only buffing with clean soft white rags. You’ll have the depth and beauty of the oil finsih with the protection of a poly finish. The selection of the Oil based urethane finish is yours also it can be had in satin-semi-gloss and gloss. Try this and let me know what you think!

Sincerely,
Ken McGinnis

-- woodbutcher north carolina

The only thing I would add to the last post is to use an oil based varnish and NOT a oil based poly. Poly is just about the hardest finish to touch up if it ever gets damaged. This is why you heard that poly isn’t a good choice for a guitar.

-- Julian, Park Forest, IL

Good point, Julian. I failed to say that the Minwax Wipe On Poly only comes in oil base. It’s durable and easy to apply.
Stan

Hi Kieran,
I can’t speak to the issue of grain fillers, as I have little experience with the process and the products. The two times I did apply grain fillers, I was not particularly happy with the consistency of the color of the finish.

Yes… my table was finished in tung oil and the oil based Minwax Wipe On Poly worked great. It only comes in oil based. The procedure I detailed was easy and effective.
Wipe on the poly with the grain and simply let dry. Sand and repeat.

Stan

raise the temp. above 75
when using oil and or varnish(others to)
if temp is below 70 can take forever to set
i did a chest last few weeks back in basement
its was 50-60 and wk later still wet. turned the heater on
75 and dry next day.

Hey everyone,

Many thanks once again for all the advice. Ken, your detailed suggestions sound fabulous—I think I’m going to try just what you’ve recommended here on the music box stand I’m also working on (also mahogany). For the guitar, I decided to go with Stan’s advice of the wipe-on poly. Sure enough, when I started working on it again, the oil on the guitar had not cured properly in several spots and was a gummy, sticky mess when I started removing it. I sanded back to the wood, restained with full-strength stain, sanded, stained again with a diluted stain, and have since applied three coats of poly (which is drying out! Hooray!). I’ll be damned if it isn’t starting to look pretty good. Naturally, there are some flaws (one area of scratches on the front I was never able to get out) but overall it’s really starting to come together in a way that’s going to work just fine for me. I also discovered that Warmoth (a company that makes raw guitar bodies in a wide array of shapes and types of wood) uses poly on their guitars that folks buy pre-finished. While some of the folks on the guitar forum echo Julian’s comments about the difficulty of repair, it seemed like an OK way to go for this project.

I’m planning to apply a bunch more coats of poly, and was wondering if I should use a wax on top of it. I did NOT use grain filler this time—I was unhappy with the look of it before and found it a real pain to work with. The open pore look and feel is just fine by me, but I wasn’t sure if that would make waxing a bad idea, of it wax on top of poly is a bad combo. I have some Briwax I got to use on my music box, which I’ve heard is good.

Thanks again for all the advice—I know I promised before and after photos, which will be forthcoming once I finish putting this beast back together.

Kieran