Acoustic Guitar Construction

Hi - and thanks for the warm welcome!

Just to get things clear in my mind. You use Tru-Oil for the pore filling too. Do you use just diluted oil as described above, or the "official" oil filler. Do you mix it with sawdust?

Another question ;-) I have read that those who use the oil on the soundboard put 1 or 2 coats of shellac on first. Does this sound like a good idea? I guess this would also give a chance to add an extra coloring to the soundboard too.

Thanks once again!

Either filler will do - in keeping with my 'minimalist' approach, I use the thinned TO for the pore filling; as it is sanded it forms a slurry with the sawdust the sanding provides, and as sanding continues the slurry is pushed into the pores.

The TO will provide a bit of amber to the wood, so once again I recommend: practice on scrap first, don't practice on the guitar :-) - though I have broken that rule a time or two.

Shellac would work under TO as far as I know. If you have worked with shellac and have the process down, that's one thing; if not, shellac must be applied evenly and not allowed to splotch.

It should be mentioned that pore filling is not a requirement. Once you set the highest possible gloss as your target, finishing becomes a whole new ball game. I have seen some gorgeous open-pored finishes, where the wood just glows and has a pleasing sheen and you just want to touch it. You can achieve that easily with the TO. Pore-filling is easy enough with my method, though, that it should not be a hurdle.
Be very certain what you are aiming for, and ask yourself if the high gloss is really your goal.

Dave

Once again, thanks for the great advice .... but the questions keep coming ... ;-)

I don't know if you know of the DVD series "A Master Class in Acoustic Guitar Making". In that series he finishes with Danish Oil - a very simple finish, seems very easy to apply and looks great.

Any experience or ideas about this kind of oil finish. If not, that is fine - I will probably be going the truoil route on my next build.

How many layers of Tru-Oil do you apply before you consider it to have a good build up? Also, how do you polish it to a gloss - if at all.

As you can see .... I am testing your patience now ;-)))

My patience is unending, as is my wisdom, sense of humor, deep human empathy, and ability to eat tacos! :-)
Actually the tacos are the only true thing in that statement, but you won't try my patience , so ask away!

Danish Oil and Tung Oil are outside the mainstream; they do give a pretty finish and are easy, but they are much more penetrating than TO, varnish etc., and hence are anathema for sound production. This is something I have NOT tried myself, however, just reporting what I have read and discussed with others. You might be very pleased with the results and, if you have plenty of time to build more instruments, even if you end up not liking the Danish, you can just avoid it in the future. In any case the methods of building and finishing in the DVD/book , if it inspires confidence in you, why not follow the instructions for finishing as described therein?

As to high gloss - once you have your finish coats on - I usually go with 10-12 thin coats - and you have let the finish cure for a week or two, you can treat the finish like any other and bring to as high a gloss as you like. I suggest using Ken Cierp's polishing method which, if it is not already posted, I'm sure he would like to share.

Your patience is unending!

Ok, I will look out for Ken's polishing tips.

One last question (maybe). Do you mask the sides of your fretboard or do you oil them too? How about the bridge? Left raw or can you oil it too (danish seems to work fine here).

The danish aproach in the videos is very appealing but I am really not sure about it. Looks great but the guy in the dvd talks about letting it absorb into the wood so it can build up. Sounds a pretty risky aproach for the soundboard but then again I haven't tried it myself!

I read recently somewhere that tru oil is used by Kinkade on his guitars. However, in his book it doesn't look like tru oil to me.

Keith

Hello...

I too am a devoted TO fan. Although I've built 10 guitars, all but one finished with TO, I did not know about the TO slurry method of pore filling. Could you please go into more detail about this method, especially the sanding to make the slurry.

TS (Terry) Paxton
TS Paxton Guitars

Keith - I usually put a little TO on the bridge unless I'm just happy with the way it looks. Usually, ebony I leave alone, EIR or anything else, I love the look of a little oil on it. I don't see why Danish would not work there as well.
I'll let others chime in on the fretboard edges as I don't have a particular opinion on that. When I bind the fretboard I do TO the wooden binding.
George Lowden uses a rubbed finish, not sure what kind, and it is rubbed to a satin sheen; Bruce Sexauer uses varnish; Dana Bourgeois offers a rubbed finish as an option, there are other top notch guys that use finishes other than spray on.

Terry - I really hope that you will share your finishing technique. There's always more to learn and since you have finished more guitars than I have I would love to benefit from your experience.

As to pore filling: I got this from a website some time ago: http://www.woodmagazine.com/materials-g ... ng/?page=2

Filling pores with a homemade slurry:

A watery mix of insoluble materials is a slurry. To Jim, that means an oil/varnish, such as (Tru-Oil), mixed with sanding dust. "The (TO) darkens the pores for contrast," he says. "I pour a liberal amount on the surface, then sand vigorously with 100-grit-the paper has to produce sanding dust."

With burlap, a towel, or an old washcloth, Jim packs the slurry into the wood. "I don't wipe off any excess slurry," he notes. "I just let it dry overnight. Then, I sand it again, adding more oil if needed. The new sanding dust blends with the original slurry and further fills the pores when I pack it in. This time, I wipe off the excess before letting the surface dry. After the second slurrying, all the grain should be filled."

That is basically what I do. I do thin the TO - I mistakenly put 50/50 in my original post, it is actually at least 4 parts mineral spirits to 1 part TO.

There is a second approach that I have been testing and getting good results. It goes like this:
Sand to 120
Sand again with 120, this time making the slurry, sanding the slurry in but not so much you cannot wipe if off with a towel, paper or cloth.
Next morning:
Sand with 150
Sand again with 150, this time making the slurry etc.
Next morning:
Sand with 220 etc etc
I got that method from a finishing book, and actually over several days, 1 coat a day, got up to 800 grit and not only was it perfectly pore filled, it was perfectly leveled and frankly quite lovely. I did the same thing using the quick dry varnish and also spar varnish, and they all turned out just right.
I think that approach is worth a try on an instrument as well.