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Stripping Guitar for tung oil finish

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Forum topic by Bigyouth posted 12-26-2011 07:19 PM 6522 views 0 times favorited 12 replies Add to Favorites Watch
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Bigyouth

4 posts in 1803 days


12-26-2011 07:19 PM

Hello,

I’m starting my next project on a used guitar body. It has a clear finish with a really good looking maple top which I want to bring out. The finish is quite thin which is why I reckon it’s more likely to be nitro than poly. My instinct was to use a heat gun and a thin chisel to remove the finish then sand it down with medium to fine sanding paper right down to the wood.

Would it be essential to use a filler then sand in order to prep for the first tung oil coat or would I be ready to go after smoothing it down the first sanding.

I have questions on how to tung oil, my current premonitions are to apply a coat then wipe it down and leave to dry. Steel wool between coats? And add coats until the wood doesn’t absorb anymore oil. 5-7 is what I usually see. For the sides i want to use a slightly darker dye. But its not terribly important until I’ve removed the original finsh.

This is then first time I’ve ever tried to strip or refinish a guitar, advice would be very much appreciated.

Thanks very much


12 replies so far

View wingate_52's profile

wingate_52

224 posts in 2029 days


#1 posted 12-26-2011 08:42 PM

I hope it strips well. I have stripped many a guitar body and headstock, but have come up against some really difficult ones, that refuse to give up their finish.Good luck.

View Lee Barker's profile

Lee Barker

2170 posts in 2310 days


#2 posted 12-26-2011 08:49 PM

acoustic or electric? The tough ones wingate is referring to are probably conversion varnish. Like iron!

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View CharlieM1958's profile

CharlieM1958

16241 posts in 3678 days


#3 posted 12-26-2011 09:12 PM

Can you put a tung oil finish on a guitar without adversely affecting the resonance? I really don’t know, but my instints tell me it might be an issue.

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

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Bigyouth

4 posts in 1803 days


#4 posted 12-26-2011 11:38 PM

It’s an electric so the effect of the finish is not so prominent as it is with an acoustic. From what I have read the use of an oil finish let’s the wood ‘breathe’ and frees the tone woods’ true brightness; although I’m not so convinced at the severity of the difference. I’m mainly doing it for the feel and the chance to dye in the sides of the guitar. The poly finish wasn’t done evenly at all, and there’s some horrible clouding; but you can see the wood colour and patterns are brilliant.

I just had a quick go of sanding with 120 and there’s no chance I’ll be getting very far. I’m gonna try the heat gun tomorrow then hopefully sanding will be more effective once the bulk is off.

View fussy's profile

fussy

980 posts in 2511 days


#5 posted 12-27-2011 07:41 AM

Lee is probably right, I doubt the heat gun will be effective short or letting the smoke out. 120 is probably too light for this stuff. I’d try 80—gently. As far as tone in an electric guitar, wood selection has nothing to do with it. Pickup construction ie., wire gauge, # of turns, magent type, strength and size. amp type (tube, transistor, hybrid), speaker choice—Celestion, EV, Eminence—will have more to do with tone. Relative density will affect sustain with perhaps a slight brightening in the high end, but much less that the other considerations.

That said, maple is a great choice. I wouldn’t seal it. Just sand to about 220, and begin applying the tung oil with 320 wet-or-dry in a circular motion. This creates a slurry that fills the grain, but on maple, that isn’t a issue. Give adequate drying time between coats, knock down with 0000 steel wool between coats, repeat with 400, 600, etc till you get the glow you want. If it’s a used guitar and the finish is original, it’s probably conversion, not nitro-cellulose. That isn’t that hard to sand. Be careful and take your time. Use a good paste wax when done.

Steve

-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

View Planeman40's profile

Planeman40

805 posts in 2221 days


#6 posted 12-27-2011 07:48 PM

If I wanted to refinish a guitar:

Stripping: Use 0000 (four “ought” which is very fine) steel wool available at your paint store dipped into brush cleaner. Squeeze out the excess brush cleaner and rub the guitar body with the steel wool. The brush cleaner dissolves the finish and the steel wool takes it off. If you do this, no sanding will be necessary and you will be ready to apply the tung oil. Some finishes like polyurethane may take some real scrubbing.

If the guitar is a solid body any finish you like will work as the guitar body has nothing to do with the tone. If the guitar is a resonant body I would have my doubts about using tung oil. Tung oil is an oil that when exposed to air turns to a wax. It will soak into the wood as an oil and over a period of days of exposure to air will solidify into a beeswax-like wax. Thus you should polish it out again after a week or so. I think a wax-soaked wood would impair the tone. If I were to refinish a resonant body guitar I would finish it with shellac. Shellac comes in both clear and a slightly orange shade. It is wonderful to use, dries quickly, sands beautifully, and can be polished to a mirror finish. One caveat however. Shellac must be fresh. If it is old it will not dry properly and will be soft and gummy. Most old guitars and old violins were finished with shellac including the Amatis and Strads so shellac has been proven by the test of time. Most new guitars are sprayed with lacquer which dries to a hard finish like shellac. There is a lacquer formulated for brushing. You may want to try the brushing lacquer if you don’t have spraying equipment. I would still prefer the shellac myself.

Planeman

-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

View Bigyouth's profile

Bigyouth

4 posts in 1803 days


#7 posted 12-27-2011 10:21 PM

thankyou for the replies,

I’ve begun sanding the top. It’s an arched top les paul body so i’ve been sanding by hand with 80 grit sandpaper. It is made from basswood and the top, I’m assuming, is maple. It wasn’t too hard to sand, I’ve gotten about half of it down to the grain, the back will be much easier as it’s flat and I’ll be able to use a hand-sander. The area’s where I’m down to the wood I lightly sanded with 120.

It was hard starting but once I’d done the first patch it became much easier. I’m always sanding parallel to the grain and i’m just progressively making my way and only sanding until I cannot see the clear finish and can feel the wood. When I do the back it will be more methodical as I won’t have to worry about the relief in the arch shape on the top. I tried sanding around the bridge and tailpiece bushings but I will have to remove them so I can sand over that area properly; I took the chance to sand the insides of the pickup routes where the original finish had seeped over.

After about half an hour:

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This is it now, after an hour of careful sanding,

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I’m very happy with the look of the grain. On the back of the guitar there is a ‘rift’, i’m not quite sure how to describe it, where the finish has acted like a filler

Photobucket

Will I be able to remove this after sanding and then finish over it, should I use a wood filler in it?

From what I have read of Basswood, it is inherently quite soft and can absorb dyes quite well. Applying a dye on the front and sides shouldn’t be too difficult and it shouldn’t have any effect on the application of the tung oil.

I’m lost on what tung oil to use, for the top I don’t want to dye it too dark nor do I want it as pale as it is natural, how much darker would it become with a ‘regular’ tung oil? I’ve heard you can mix it with a shadier dye to bring out more colour and grain in the wood.

Shellac sounds great but I’ve heard it takes a lot of skill to apply correctly, also I really love the look of a tung oil finished guitar with well defined natural grain.

View hObOmOnk's profile

hObOmOnk

1381 posts in 3587 days


#8 posted 12-28-2011 03:35 AM

Note: Antonio Stradivari used a drying oil (linseed or walnut) to seal the wood on his violins, then a top coat of varnish made from a drying oil and natural resins – no shellac.

Drying oils; e.g. linseed, walnut, tung, etc.; cure to a hardened finish through polymerization, and not a waxy state. When properly applied and cured, a drying oil finish on an acoustic musical instrument will not adversely affect the sound.

Blessings,
Bro. Tenzin, OFI

-- 温故知新

View hObOmOnk's profile

hObOmOnk

1381 posts in 3587 days


#9 posted 12-28-2011 06:27 PM

Drying oils; such as linseed, walnut and tung, DO dry and harden (polymerize) completely when applied properly—- it doesn’t take years for this to happen. This has been known and proven for hundreds of years, both empirically and scientifically.

The Golden Age musical instrument makers used drying oils and cooked oil-resin finishes. These types of finishes are still used today by artisan musical instrument makers and restorers. Even modern Ukulele makers and Kentucky dulcimer makers will often, but not always, use the proven oil finishes for their instruments.

NOTE: I am not arguing your position. I am simply stating facts that are known to me.

Back to the OP’s request: A modern oil-based wiping varnish, any brand, might be the simplest and safest solution. Start my completely striping the old finish and carefully prepping the wood. If you wish to use whole-oil finish, then consider a gunstock oil, such as Tru-Oil from Birchwood Casey. If you wish to use real tung oil, then consider using a heat-treated (partially polymerized) tung oil. This will dry a little faster than raw tung oil and will result is a greater sheen when rubbed out.

Blessings,
Bro. Tenzin, OFI

—just a lowly monk, former chemist (clinical and toxicolgy), consultant to the paints and finishes industry (especially traditional finishes), and a wood worker and restorer with more than 40 years experience.

-- 温故知新

View Loren's profile

Loren

8295 posts in 3108 days


#10 posted 12-28-2011 08:27 PM

There may be sanding sealer lodged in the end grain particularly. This
stuff can throw of the appearance of a refinishing job. The stuff in the
end grain is really hard to get out, unfortunately. Test end grain areas
with your finish and scrape and sand more if you encounter this stuff
and find the appearance ugly.

View wingate_52's profile

wingate_52

224 posts in 2029 days


#11 posted 12-29-2011 12:14 AM

I Danish oil electric bass guitars after a coat of sealer, othewise the wood acts like a sponge. I really like to use Rustins Plastic Coating, let down 4 to 1, and apply 3 coats with a cloth and get an oil like finish that is hard and tough and resistant to everything.

View Daver725's profile

Daver725

13 posts in 1796 days


#12 posted 01-03-2012 03:59 AM

I’ve had good lucke with truoil on several guitars. I would say tung oil would be about the same.

Dave

-- Insanity, doing the same same thing over and expecting different results.

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