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Hello, Can anyone tell me if even a correctly done Tru Oil finish could have a negative effect on the sound of a european spruce top acoustic guitar. I'm trying to get a soft natural satin finish and an optimal and unconstrained sound. I've heard differing opinions on this. Anyone with first (or even second) hand experience? Thank you.

Tru Oil is indeed a great finish for all guitar tops. I have been using it for many years and can say that it is a great guitar finish. It does not penetrate or saturate the wood, requires no spray equipment, is user friendly and very forgiving. It won't weight down the top, crack, chip, peal, blister, or craze. Repairs easily and is very durable. It can yield any look from matte to high-gloss.
George Morris, Vermont Instruments

I used true oil on my last guitar (yes even the top) and it sounds sweeter than any guitar i have made.

it has a mad rose back and high grade european spruce top ( will post some pics next week).

when i was taught to do an oil finish on guitars my tutor mike hobbs told me that as long as burnish the wood with with micro mesh up to 12,000 grit the oil will not penertarate far into the wood.

This is becouse the top has effectively been burnished and the oil sits on the serfice like a varnish.

also the secret to a realy good oil finish is in the preperation of the wood and micro meshing the top will help bring the finish to a a suitable conclusion.

many people will disagree and say in no way should you use an oil finish on a top but i have two wonderfull sounding guitars here that say otherwise.

At the end of the day its your choice but i will continue to use tru oil on SOME of my guitars when it suits the job.

that said an oil finished does sound slightly different than a laqure finished top but its in no means a bad comparason.

if you are worried about the oil penertrating the wood you could allways use a shellac seal coat under the tru oil.

Joel.

If I'd had any tru-oil here (i don't) I would use it on a piece of packing grade spruce, and after a full buildup and curing, sand it all off with fine paper. I suppose it should not be hard to see and asses how deep the penetration is....

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Build log

when i finished my first guitar i was told to put an oil finish on it becouse it was a great begineers finish.
i did this and i followed the tutors advice to the letter until the final stage when i decided to wax the guitar with paste wax against my tutors advice dont ask me why it was my first guitar.

i used a dark wax for the rosewood back and sides and a clear wax for the top.
whilst had moved on to the top i had the dark wax next to the clear wax and intent on looking at the top i promply put a big load of the dark wax on my rag instaed of the clear stuff.
I did not notice before it was too late and i had a rubbed grat big long streaks of "antique mahogany" wax all over my top.
becouse i was doing this at home not at college i thought i would compansate buy covering the whole top with the stuff

of course i had to strip the whole top back and refinish it

the oil finish (chestnut finishing oil in this case) came off easily with 240grit finishing paper and the oil had not penertrated at all.
this convinced that if done properly the oil will saturate the wood.
the only negative result was that i now had a top that was too thin under the sound hole.
This was remedied with a 1mm thick pick gaurde made from curly mahogany That was glued over the thin spot to act as a strengthening patch and a pick in one go.

I was really worried how this would effect the sound but i have to say its one of my favourate sounding guitars it wonderfully rich and well rounded.

any way i digress the fact is oil will penertrate the top to some extent but you can limit this by either burnishing the wood or using a seal coat.


Joel.

Thanks for the post George. Any chance we could get you to post your finishing schedule for Tru-Oil?
Thanks
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Thank you one and all for your replies. I guess the only question I have left is: In what way is the sound different from a lacquered finish?
Thanks,
Rene'

rene,
that question opens up a whole can of worms.

every guitar will sound diferent but many makers will not use an oil finish on a top becouse they say it will absorb into the wood and thus impede the vibration of the top and thus effect the "Tone" of the guitar.

i dont think this is the case with a properly done finish but i do think that oil can influence the tone of the finished guitar in the same as a laqure can influence the tone of the guitar.

laqure can severly impede the function of the top as well if done incorrectly and its put on to thickly.

what i am trying to say is that each type of finish has its own merrits and can impede the sound of the guitar if not done correctly.
but they can also add a a positive to effect to sound of the guitar when done in the right way.

Joel.

Thanks Joel.
What I'm asking is this: hypothetically, all things being equal, that is if you had two of the EXACT same guitar (Alpine Spruce top, Mahogany back and sides) and did a perfect shellac job on one and a perfect oil finish on the other, how do you think they would sound in comparison?
Rene'

To be honest i doubt that there would be an audible differance between a shelac finish and a oil finish.
how you build the guitar such as top thickness,brace shape etc etc is going to have much more of an effect.

that said i thik a tru oiled top gives the guitar some very natural "woody" overtones as it in my opinion does not "color" or "damp" the sound in the way a laqure can.

but if you build to guitars exactly the same all the way but used different finishes on the top they my sound different but it may not have anything to do with the finish

i think what i am trying tomsay is that while i like oil finished guitars in some cases it may not work for someone else using the same method.

Joel.

If you are worried at all about penetration, then use an undercoat of shellac - Tru Oil goes on great over shellac.

My first several guitars were finished with Tru-Oil. The finish has stood up quite nicely. I used micro-mesh on the bare wood before applying the finish so the top was burnished to a nice gleam, and thus very little penetration into the soft wood. I learned this method from David Freeman at Timeless Instruments where I learned the craft. I would do 8 or 9 session on the top and 12 to 13 on the back and sides. I still have the first guitar I built with the Tru-oil finish...it is still one of the best sounding guitars that I have built...is it the finish? That is such a subjective question...it could be many different things...not the least being personal bias...

David

I would add a cavaet to this.....95% of this discussion applies only to Tru Oil (Birchwood Casey), which is actually closer to a varnish in its formulation than a traditional finishing oil.

I dare say one might not get the same result using tung oil or danish oil on the soundboard.

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The member formerly known as erikbojerik....

i have used danish oil in the same way and got the same results but without they glossy finish you get with tru oil.

i have also seen quite a few danish oil guitars finished in this way as it was popular when i was a student they all sounded pretty good.
but i suppose thats subjective.
i understand the point about penertration though and fully accept it as a fualt to the method.

Joel.

Thank you Joel and everyone for your great answers. I finally got it.
Rene'

It seems that many threads discussing the Tru-oil product quickly become infused with other types of oil finishes. I have seen many warnings of oil penetrating the wood and how this is a negative. The way I was taught and my limited experience leads me to believe that the Tru-oil properties keep the product from deep penetration. The caveat to that is I was taught to wipe on/wipe off extremely thin coats Tru-oil. It could be that these very thin coats work with the product to keep more on the surface than other oil type finishes.

Tru-oil is a very user friendly product that imparts a slight amber color and has excellent tonal qualities. A luthier that I admire is David Hurd (Left-Brain Lutherie), who says that “Tru-oil is a thin and durable finish that allows the instrument to vibrate more freely than thicker layers of finish”. This is a very common finish on ukuleles but is also used on guitars. I have finished two instruments with Tru-oil and I’m very pleased with the results.

This is a Tru-oil finish but completed. This is before leveling and polishing.



Philip

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aka konacat

If you think my playing is bad you should hear me sing!
Practice breeds confidence and confidence breeds competence. Unfortunately, I'm stuck in practice.

Strange, a double post.

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aka konacat

If you think my playing is bad you should hear me sing!
Practice breeds confidence and confidence breeds competence. Unfortunately, I'm stuck in practice.

Anyone used the birchwood casey wood sealer and filler under a tru oil finish?