Tru-oil vs. French Polish

Hello,
This is my first question in this Forum. Actually not a vs. question, but rather a compatibility issue: I really like Tru-oil for its ease-of-use and soft sheen you can achieve. I've used it on a number of banjo's I've built and have been pleased with the results. Lately, I've been interested in trying my hand at French Polishing a Ukulele. I am wondering if it's possible to French Polish overtop of a thin base coat of Tru-oil to speed the French Polishing process up a bit. I'm not interested in spraying or complicated technique's at this point. Any and all opinions, most welcome.
Thanks, Joe

Yes it is, but you might want to try an alternative: doing a couple of coats of epoxy and then French polishing over that.

I don't really see how it will speed it up. The first few applications of French Polish can go on within an hour (or less) of each other. It's only when the film builds that you have to let it harden longer. You are also risking problems with Shellac over Tru-oil. I'm fairly certain that it will stick to it but there is always the possibility that it will craze.
You can always brush (or spray?) the first few coats of Shellac on. It does take a bit of practice to get an even film. You can always use the pad on top of those brushed coats. Even though I've done countless hours of French Polishing I no longer bother. I just brush on Spirit Varnish. Takes but a fraction of the time once you have mastered the brush.

Thanks for the comments!! I guess my reason for doing a French Polish is just to do one and get it out of my system. I might hate it, but for the moment I'm intrigued by this very old-style, traditional method. I was also wondering about the merits of using pumice and solvent to fill the grain or skip that and go for a filler like Timbermate. I've notice a trend towards non-filling open grain wood. As you can tell, I'm a novice at finishing. The wood type I'm using is mahogany.

Try a coat of Sealcoat Spray Shellac http://www.homedepot.com/h_d1/N-5yc1v/R-100176744/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053 first, followed by a very small amount of talc applied with a damp (with Denatured Alcohol) applicator. I use a ~1" square of an old white wool sweater wrapped in a piece of cotton T-Shirt. Slowly add 1lb cut shellac to the applicator as it starts to pull.

As Michael said, yes you can - keeping in mind that there could be glazing issues depending on just how well cured the tru-oil body is before you go ahead with the french polish.

Our method is actually the other way round: FP first and then TO on top of that. We've found it is really easy to touch up the TO finish - though I'm sure with the right technique you can also do a quick rub down of scratches or glitches in FP.

As to grain filling with pumice, it really depends on the wood - at least it has for us. So we always do a test on some scrap wood first. For example, I don't like the look you get with pumice-filled rosewood unless you add some ebony dust to the mix. The fine rosewood dust is lighter than the wood color, so you get lighter colored streaks in what was formerly the deeper (and therefore darker) pores. By adding a little ebony dust, you can keep the filled pores a darker color, which I think looks better. But of course YMMV.

EDIT: With other woods, including maple, cherry, mahogany (sometimes) and vaious others, we've had excellent results with shellac sealing and pumice filling.


SECOND EDIT: You can also use TO to do the pore filling. There are two methods I know of:

One is to use a sanding pad or linen while applying the tru-oil. The abrasion develops a slurry that pushes in and fills the pores, much like the shellac/pumice method. Let dry well, sand down afterwards, repeat until done.

The other method is to push the tru-oil into the pores with your finger, let dry, sand down, push more TO in, let dry, sand down.... Take your time and repeat over and over until you get a really smooth, glassy surface when you apply a coat of TO. I like this method better than the other, but have found that some very slight imperfections can show up months later as the varnish continues curing and sinking down deeper into the pores.

One way or the other, TO is not a finish I'd recommend to anyone who's in a hurry.

Open pored glossy finish looks a little odd to my eye. As though the wood has suffered some sort of contagious disease. Maybe it's what one is accustomed to but I think it looks much better with a dull or matte finish.
I've only tried the more traditional forms of grain filling: Pumice method, Silex filler, Oil sand method and egg white/wood dust. They all work. They all sink over time. Be prepared to do several applications over a period of 2 or 3 weeks. That will minimise the sink back.
Even though I essentially use Shellac, I believe that an Oil finish straight onto wood shows the grain at it's best. It's a pretty easy test to do - one half of an off cut with Oil, the other French Polished. The only reason I use brushed on Spirit is for pragmatic reasons.
I used to spend some 20 hours+ on French Polishing a Guitar. I thought that excessive, considering the number of hours involved in the woodwork. Some folk claim to do well over 40 hours! It's a form of madness.

Good points, Michael.

If you don't like the glossy finish you get with tru-oil you can (carefully) buff it down to a satin or matt finish with extra fine sanding pads. A lot of people use fine (000 or 0000) steel wool for this, but I find you get a much smoother, finer grained finish using aluminum oxide pads.

Certainly a lot to think about. Thank you all for the advice and council... one and all!

how i finish with tru -oil is to apply the first coat, rubbing the TO in with fine wire wool.

leave a day, gently sand, recoat with the wire wool method, leave a day

then when dry gently rub over with fine wire wool until smooth to the touch.

then coat with TO using a cloth, leaving to dry for 24 hours inbetween coats. i find 4-5 coats is fine.

Strummin simon said:

how i finish with tru -oil is to apply the first coat, rubbing the TO in with fine wire wool.

leave a day, gently sand, recoat with the wire wool method, leave a day

then when dry gently rub over with fine wire wool until smooth to the touch.

then coat with TO using a cloth, leaving to dry for 24 hours inbetween coats. i find 4-5 coats is fine.

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Just wondering if you get small pieces of the steel wool imbedded in the TO finish when applying it that way?

I've always used my finger to rub multiple fine coats of TO in over several days. Using steel wool and/or fine sandpaper between coats i sometimes notice a bit of steel wool getting trapped in the finish, but can usually get it out.

I like TO for it's ease and safety,....no fumes to worry about and use it on a lot of things,.....mostly gun stocks though and some bridge touch ups or when i've made a new bridge. Never heard of applying it with steel wool though.....

NOT MEANING TO HIJACK THE THREAD, BUT HOW DOES THE TRU-OIL DIFFER FROM TUNG OIL. is the result superior?

That depends what you mean by Tung oil.
Pure Tung oil is more like finishing with a thin version of linseed Oil because that's all it contains - tung oil. It doesn't build very well and offers very little in the way of protection. Tru oil acts similar to a thin Varnish. After multiple coats you can buff it to a pretty high gloss, although I wouldn't call it a hard surface finish.
Just to confuse matters some 'Tung oil' is a mixture of drying oils and modern Resins, very similar to Danish Oil. It sort of ends up somewhere between Pure Tung Oil and Tru-Oil.
It's all very confusing but it's the way that manufacturers market their product.
Personally I would stay away from the Pure Tung Oil. Danish Oil and similar products are fine if you are very careful with the instrument. The good news is that if the wood starts to look a little grubby it is very simple to apply more Danish oil.
Tru Oil tends to be the thicker of these finishes, builds faster and will get you to gloss. It won't offer that much more protection than Danish Oil, the gloss can be very deceptive in this case. Matte or Gloss, any finish that is largely made up of a drying oil does wonders for the aesthetics of wood.

I don't mean to split hairs but french polishing is a technique and not a type of finish although most french polishing is done using shellac based finishes. Tru-oil is a brand name of a linseed oil based finish. Here is a great description of using it. http://www.lmii.com/carttwo/truoil.htm

This has been a subject of discussion many times. William King's method is probably the easiest and most simply explained. It is in the archives of this forum - just do a search.

i ve never had problem with bits of wire wool left on the wood.
i apply the TO with the wire to help fill in any pores.

then inbetween coats rubbing with wire wool to get a smooth to the touch finish.

this is just my opinion on how to do it, it works for me after trying several different ideas.

i'd look at william kings method if i could be arsed to search for it!

You ought to be arsed! You might learn something

Strummin simon said:

...i'd look at william kings method if i could be arsed to search for it!

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Never mind, it wouldn't have been of any use.

W.K uses Watco Danish Oil, not Tru-Oil (and actually makes no mention at all of Tru-Oil anywhere on his site, at least as far as I have been able to determine using google's advanced search and every imaginable (mis)spelling of Tru-Oil). The method he describes is not applicable to Tru-Oil - at least not directly.

And BTW, Tru-Oil has been used in gunstock finishing for years and there are plenty of sources out there describing various methods of use with regard to pore filling, application, sanding, thinning, finishing, etc. etc.

"Waterlox" is a really nice "tung oil finish" that is technically a "long oil varnish" since it is a blend of tung oil with alkyd and phenolic resins. It may provide better moisture protection than Watco or TruOil, and it goes on beautifully over epoxy pore fill/sealer for a hybrid finish.

thistle3585 said:

I don't mean to split hairs but.... Tru-oil is a brand name of a linseed oil based finish....

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Me neither, Andrew, but linseed oil (polymerized) only makes up about 11 percent in the tru-oil mix, so I don't think I would really call it "linseed oil based".