Thread: Top Doming/Radius Preferred Method - Acoustic

Hi Riggsy,

There arent that many acoustic builders here and Im a bit rough and ready but what I do is get anal about the bracing shape. I make it 1mm more pronounced than the final instrument. I then use playing cards or a stack of office paper offcuts on my workboard to get the shape of the front/back Im gluing up but only where the braces are. Add bracing, glue and a couple of bricks wrapped in a tea towel and its done. I am very amateur and build on the kitchen bench so I dont think it will work for a production environment. It works for the three or four instruments I do a year.

As for tap tuning David Hurd (Left Brain Lutherie) threw me for a spin when he said he couldnt see the point of tap tuning a free plate as its behaviour changes when it is anchored and again when it encloses air. Very fair point that I havent resolved. What I do since then is ensure there are no dead spots in the top or the back.

There was a great program on RN last week on Smallman and Williams. The sound of his instruments was a revelation to me. He said that it was the thickness of the soundboard that makes the difference, so Im chewing all that information now. The lattice bracing evolved to support a very thin soundboard. The link for the podcast is here RN Into The Music - 28 November 2009 - Name's Greg, not Jose - Guitar Maker Greg Smallman FWIW the only tute Ive seen on lattice bracing is in Graham McDonald's Bouzouki book.

Im very curious to hear your progress, BTW you may also find more knowledgable folk on the anzlf.com forum.

Seb - Thanks for the input and the referral to the RN podcast. While I understand that some folks build the radius into their bracing, I am yet to have been told why they think that this is a better way to go...

Thoughts?

Originally Posted by highfieldtonewerks

I am yet to have been told why they think that this is a better way to go...

Thoughts?

Cause that is the way I was taught..... traditionnnnn [ame="http://www.youtube.com/watch?v=gRdfX7ut8gw"]YouTube- Broadcast Yourself.[/ame] Seriously, I think its easier to put it into the bracing. There is a risk of small "folds" developing in the soundboards if the ask is too much but that is when I cut pleats. Other than that I dont know.

Originally Posted by highfieldtonewerks

Seb - Thanks for the input and the referral to the RN podcast. While I understand that some folks build the radius into their bracing, I am yet to have been told why they think that this is a better way to go...

Thoughts?

The only thing holding the arch while the top is on the workboard is the soundhole clamp (its holding the top hard against the workboard. If you don't shape bracing to fit the arch then as soon as you pull the guitar off the workboard you'll lose most of if not all of the arch. String tension alone on a classical wont keep the lower bout arch.

Kiwi - An accurate statement, indeed. With the percussive nature of the flamenco and tradition dictating a non-radiused sound box, that is how we build our Andalusian model.

Our Grand Concert is built on a modified Hauser platform with a 31ft radius to the top and a tighter one for the back. The thread was started to get people thinking about why we radius the soundbox (or don't in some cases) and to get an idea as to what fellow builders think about doing so.

So many of us build by tradition/rote without knowing why... oh to go hang out with Somogyi, Caldersmith, Haile, Fleta, Huipe and the like for a while, ay?

Cheers and thanks for the input,
Riggsy