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Sanding My acustic 12 String
http://luthiersforum.com/forum/viewtopic.php?f=10137&t=52589
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Author:  Shagamatula [ Wed Oct 30, 2019 3:11 pm ]
Post subject:  Sanding My acustic 12 String

Hi Guys, I’m an amateur guitarist and I have bought a low priced 12 string (£130). This has no sentential value to me. One issue is its quite, doesn’t sound loud enough (new strings). It came factory varnished and I was wondering if I gently sand the lacquer away to reveal main wooden carcass, would I benefit in sound level. Also what can I use to protect the wood after I sand it.

Really really appreciate if anyone can help thanks...

Author:  Bryan Bear [ Wed Oct 30, 2019 3:33 pm ]
Post subject:  Re: Sanding My acustic 12 String

Collect a lot of responses here before you go sanding anything. Sanding finish off and refinishing is more involved that people assume from the get go. It is usually good advice to NOT do it. Visually, I can almost guarantee you will not be happy with the results if you don't have a lot of guitar finishing experience.

If the finish is heavy, it will have an effect on tone but I'm not sure this is the easiest place to start. Tell us about the guitar. What size/shape is it? Is it a plywood top or solid (sanding a ply top is another danger if you don't have a lot of experience)? What strings are you using?

It may be that this guitar is over built and brace shaping (WITH PLENTY OF ADVICE FROM HERE) could be an option. Are you able to get pictures It may be that you shouldn't expect much no matter what. . .

Author:  Conor_Searl [ Wed Oct 30, 2019 4:13 pm ]
Post subject:  Re: Sanding My acustic 12 String

My first thought is if it is a plywood guitar, will a person actually get any more sound(tone) out of it by removing the finish? Enough to make it a worthwhile endeavour?

Another question comes to mind, are you just trying to fix a particular problem (lack of volume) or are you looking to have fun experimenting? If your goal is having fun and experimenting with things like brace shaving and re-finishing then this is as okay of a place to start as anything else I suppose. Keeping in mind that your experiment isn't something most of the people in the luthiery world spend much time doing and you're going to get all kinds of responses about how doing those things with a guitar like you've described isn't economical or worth doing. But if you're just trying to solve a particular problem with this instrument you'd probably be better off selling the guitar and looking for another guitar that suits you more.

From personal experience, removing the finish off of plywood is extremely risky. Sand through the top ply and you're in a world of trouble. Not only do you end up with a super ugly spot where the grain runs across the surrounding grain, but the glue used to laminate the plys prevents any simple re-finishing.

Author:  Chris Pile [ Wed Oct 30, 2019 4:46 pm ]
Post subject:  Re: Sanding My acustic 12 String

OP...… DON'T, just DON'T. You'll be sorry.

Author:  B. Howard [ Thu Oct 31, 2019 7:24 am ]
Post subject:  Re: Sanding My acustic 12 String

No! Removing finish will not miraculously give you the tone of angels!

I am always amazed how players get convinced that the thing affecting their tone is few mils of plastic resin on the surface. Literally .0001% of the actual instrument.....

Author:  jfmckenna [ Thu Oct 31, 2019 10:51 am ]
Post subject:  Re: Sanding My acustic 12 String

Some guitars do indeed have ridiculously thick finishes though. Ovation is a good example. I've not actually measured it but it's practically 1/16th inch thick. In fact I've wanted to do an experiment like what the OP is suggesting at some point but have never gotten around to it. I do hypothesize however that if there is a thick finish on a guitar then removing it will change the tone.

I'm not going to recommend that the OP does it, but if you do please report back :D

Author:  Bryan Bear [ Thu Oct 31, 2019 11:23 am ]
Post subject:  Re: Sanding My acustic 12 String

Removing an excessively thick finish will change the tone but by how much is the question. Guitars with very thick finishes tend to have other things working against them as well. Things that likely play a larger role in the sub-optimal tone output. When we make hand made instruments and build them to be light and or responsive, the film weight has a much bigger impact that it would on a laminate top with 2x4s for braces.

Author:  surveyor [ Thu Oct 31, 2019 12:17 pm ]
Post subject:  Re: Sanding My acustic 12 String

Maybe get an amplifier?

Author:  B. Howard [ Fri Nov 01, 2019 5:28 am ]
Post subject:  Re: Sanding My acustic 12 String

FWIW, I have seen very thick finishes on wonderful sounding guitars. Some vintage Gibby and martins have finishes 13-15 mils thick! And these are some of the most coveted tone machines.

I have seen very thin satin conversion varnish finishes on imports that measured barely 2 mils and the guitars sounded like crap.... perhaps the hot glue gun construction played a larger role on these $75 instruments than the finish?

Author:  Mark Mc [ Sat Nov 02, 2019 7:48 pm ]
Post subject:  Re: Sanding My acustic 12 String

It is a cheap guitar, and it sounds like a cheap guitar. What makes you think it is the varnish on the cheap guitar that makes it sound thus? If you sand it off you will just have an ugly cheap sounding guitar.

Author:  Shagamatula [ Sun Nov 03, 2019 10:30 am ]
Post subject:  Re: Sanding My acustic 12 String

Ok thanks everyone for response, I’ll leave it as is maybe buy a pickup and use an amp. But thank you all for the advice.

Author:  Freeman [ Sun Nov 03, 2019 11:46 am ]
Post subject:  Re: Sanding My acustic 12 String

Paul, I am in complete agreement with everyone who says the thickness of the finish has little or no effect on the sound of a guitar, but there might be some other things we can recommend to help. What brand is the guitar, maybe show some pictures. What strings and tuning(s) are you using (this can be very important for a 12 string)? It might be that a pickup and amp are the solution - I think some work better with 12's than others.

Author:  Shagamatula [ Sun Nov 03, 2019 3:38 pm ]
Post subject:  Re: Sanding My acustic 12 String

https://www.brunswickguitars.com/guitar ... tural.html

Here is a linkk...

Author:  Freeman [ Sun Nov 03, 2019 8:01 pm ]
Post subject:  Re: Sanding My acustic 12 String

Shagamatula wrote:
https://www.brunswickguitars.com/guitars/200-series/brunswick-dreadnought-12-string-natural.html

Here is a linkk...


OK, a few comments. I am not familiar with that brand but it looks like a decent inexpensive line of guitars. At that price I am quite sure that the top, back and sides are all laminated woods - that often results in less volume than the use of solid woods. i'm also going to guess that the guitar is fairly heavily braced which comes with the price point, that also will kill a lot of volume. Last general comment, believe it or not, 12 string guitars are not inherently loud - the relatively heavy bracing required to stand up to all that tension can cut volume a lot (I own three twelve strings, some of my little parlor guitars are significantly louder).

I would guess that Brunswick would recommend light gauge strings (0.010 to 0.046 or so) for tuning to concert pitch, that will give you somewhere around 250 pounds of total tension on the top. I happen to be a big fan of tuning a twelve string down one or two semi tones, it won't make it any louder but it seems to change some of the jangle to more of a roar. Some people us "silk and steel" strings on a twelve for their reduced tension, I've never been a fan and think they too will reduce the volume. Don't go heavier that 10's unless you do plan to tune down.

Last and far from least, you might want to add a pickup and amp. I have had good luck with the little piezo discs that mount under the bridge (I have had less luck with UST pickups - they are often hard to balance across the strings). Don't remove finish, that won't accomplish anything.

Good luck, report back.

Author:  Shagamatula [ Mon Nov 04, 2019 10:56 am ]
Post subject:  Re: Sanding My acustic 12 String

Thanks a million Koa really appreacate your time and advice. And also everyone else thanks.

Author:  jfmckenna [ Mon Nov 04, 2019 2:04 pm ]
Post subject:  Re: Sanding My acustic 12 String

I thought it was a common perception in the luthier community that the thinnest finish possible, especially on the top, is benificial to tone. A finish adds mass, damping and even stiffness to the top so it's doing something. I think I remember reading a post from Trevor Gore where he was doing some consulting for a guitar factory and noticed that the unfinished guitars sounded considerably better then the finished ones, and in fact the companies higer offerings that had the high gloss finish sounded the worst because to get that high gloss they had to put gobs of finish on it to polish it out to a mirror finish.

But anyway... As mentioned if the guitar was never that good in the first place then yeah you probably won't notice much of a difference. Shaving braces would be a much more dramatic affect but that can ruin an instrument too. Again it's a cheap guitar and if you don't care too much about it and are an inquisitive person then you might want to do something to it. That's what I used to do when I first started down this luthiers path a long time ago.

Otherwise just play it.

Author:  Bryan Bear [ Mon Nov 04, 2019 2:37 pm ]
Post subject:  Re: Sanding My acustic 12 String

jfmckenna wrote:
I thought it was a common perception in the luthier community that the thinnest finish possible, especially on the top, is benificial to tone. A finish adds mass, damping and even stiffness to the top so it's doing something. I think I remember reading a post from Trevor Gore where he was doing some consulting for a guitar factory and noticed that the unfinished guitars sounded considerably better then the finished ones, and in fact the companies higer offerings that had the high gloss finish sounded the worst because to get that high gloss they had to put gobs of finish on it to polish it out to a mirror finish.

But anyway... As mentioned if the guitar was never that good in the first place then yeah you probably won't notice much of a difference.


I remember reading that anecdote as well but agree that the effect is probably smaller/relative depending on the construction of the guitar itself.

I also remember reading Alan Carruth saying that it can be easy to get a 12 string to be loud since it has twice the horsepower but you only need to increase the thickness and brace height 25% to double the stiffness. So you can end up with a slightly heavier top that gets much more energy to move it. That was what lead me to believe that this guitar is likely heavily over braced. Keep in mind, I have no experience with 12 strings.

However, reducing the bracing weight is something that would be best done with advice from people with experience (not me).

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