Stress-Free Assembly (Full Version)

Foro Flamenco: http://www.foroflamenco.com/
- Discussions: http://www.foroflamenco.com/default.asp?catApp=0
- - Lutherie: http://www.foroflamenco.com/in_forum.asp?forumid=22
- - - Stress-Free Assembly: http://www.foroflamenco.com/fb.asp?m=184540



Message

Ruphus -> Stress-Free Assembly (Dec. 3 2011 11:06:48)

Guess that´s what every carpenter apprentice learns, or at the very least hears about. And even metalworkers should ( unlike the guy who welded my yards gate, which always makes a banging sound with temperature changes during day / night switch ).

Lester DeVoe for one seems to have covered that inconspicuous matter pretty well.
When I noticed him explicitely mentioning advance with stress-free assembly on his website; I imagined how improvement in such realm might help with a guitars acceptance of climate changes.

And indeed, eventhough I try to avoid climate extremes ( and thus left the guitar in a relatively controlled storage during summer / hence, at RH below ~ 38% temporizing to less precious guitars ) it appears to stay pretty stable despite temperature and humidity differences of ~ <8°, 10% and more between storage and practice hours in the living room.

Though fancying minute protrudings of fret wire after long while in too dry air, me sees no perceivable changes with the top and feels no alteration of the action.

Most remarkable however is how stable the tuning stays.
Once new strings have set in, you basically get the same tuning situation that you put the guitar in its case with, last time.
Even after weeks ( like with those rests during summer months ) it only needs a single tweak here or there before you´re ready to go.
I have experienced well preserving guitars before, but this one seems to top them all.

This while I assume the conditions during assembly to have been very different from the ones here.
In California where Lester is situated, humidity ought to be rather high ( mabye around 60% average in Nipomo, I guess?) while here its is about 30% during summers and during winters >40% at best.

A not too small climate difference the guitar has to cope with, which it however does remarkably well.
Could be merrits of stress-free assembly to appear like nothing too spectacular, yet I though the effects to be worth mentioning.

Ruphus



Stephen Eden -> RE: Stress-Free Assembly (Dec. 3 2011 17:48:11)

Are you speaking of humidity stresses? Or force stresses? I assume most if not all proffesional guitar makers work in a humidity controlled environment. Forcing the wood into 'stressed' situation is more than likely done by alot of luthiers. Doming the back! (I say the back because Anders doesnt dome the top).



jshelton5040 -> RE: Stress-Free Assembly (Dec. 3 2011 18:23:45)

quote:

ORIGINAL: SEden

Are you speaking of humidity stresses? Or force stresses? I assume most if not all proffesional guitar makers work in a humidity controlled environment. Forcing the wood into 'stressed' situation is more than likely done by alot of luthiers. Doming the back! (I say the back because Anders doesnt dome the top).

Stephen,
I interpreted Ruphus (and Devoe) to be referring to assembling the guitar without stress. This is of course impossible as anyone who builds a guitar will soon discover; however minimizing stress during construction seems like a reasonable goal to me and I suspect you agree.



Ruphus -> RE: Stress-Free Assembly (Dec. 3 2011 18:59:59)

Well put, John!

In absolute terms stress-free shouldn´t be able to provide the tension needed for a resonating unit ( eventhough it has been amazing for me to realize how for instance suspended necks - merely clamped by string pull-lever - are working / allow tension pretty well. - Think to remember that Hauser even partially used such concept), by the nature of it.

Yet, reducing stress where possible seems to matter a lot in respect of form stability.

At least to me it has been surprising to see how stable a guitar can stay over long time and yet despite climate changes.

Ruphus



TANúñez -> RE: Stress-Free Assembly (Dec. 3 2011 20:17:44)

quote:

(I say the back because Anders doesnt dome the top).


Is this right Anders? I always assumed you did.



Ruphus -> RE: Stress-Free Assembly (Dec. 3 2011 23:02:54)

I think to remember that Anders would be doing both ( or was it appreciation of both?

Matthias Dammann is one of those who won´t dome tops.
He says something to the extend of convex form to decrease property of flexibility ( vibration / and pardon my English ), which seems of sense in general.

He also points to that plantillas are harder to move the bigger they get. ( Increase of impact / energy required.)

Which on the other hand could be indicating why violins are traditionally domed ( as they supposedly can use some damping for to not fold / get brittle / flat ) and why such a stiffening feature could be suiting lesser to guitars. - Despite better optics of convex surfaces.
-

BTW; it was said some threads ago that guitars with greater corpus would be louder.

To my experience it is rather the other way round, with smaller bodied ones actually appearing more responsive.

- And the tiny violine will drown them alltogether, though, admittedly: That also ought to do with the great force a bow can exert.

Ruphus



kintla -> RE: Stress-Free Assembly (Dec. 4 2011 4:31:41)

Hi Ruphus, I tracked you down! I'm now in Colorado and should one be looking for a dry climate I think here would suffice. I tend to believe what has been passed down as gospel about humidity, ie, keep your instrument in an enviornment as close as possible to the one it was built in. However we all know that is an ideal situation, and besides, unless one knows exactly the humidity level when the guitar was constructed, futile. But assuming normal parameters we can guess a bit and be safe. How all this affects the tone of a guitar is a mystery to me, but I am sure it does, just as a multitude of other things do. It seems some guitars are quite able to hold their tune better than others, in my case cedar seems better than spruce, but I wouldn't want to generalize on that. And this business of "stress" in building, I would like to hear more about it, how luthiers approach it, what effect doming has, etc.

Just muddying the waters a bit. Hope you are enjoying that DeVoe guitar Ruphus.



Richard Jernigan -> RE: Stress-Free Assembly (Dec. 4 2011 5:51:17)

My '73 Romanillos has a relatively flat top, compared to his instruments that immediately followed it. It has the plantilla, body depth, bracing pattern, etc. of a 1950 Hauser I that Romanillos studied. Interviewed by the well known English luthier Kevin Aram, Romanillos said that in building the '73 Romanillos made so famous by Julian Bream, constructed just after mine, he increased the doming of the top, "to put more tension into the guitar."

The doming of the top is not carved into it, as in a bowed instrument or an arch-top guitar. Instead it is produced by arching the braces slightly, forcing the top plate into a hollow in the workboard (solera) when the braces are glued on, and arching the bridge. This produces stress in the top. Romanillos thought this was a good idea, and Bream said the resulting guitar was the best he ever had. Earlier Bream had bought two 1971 Romanillos guitars. One of them was the guitar he debuted the Villa Lobos Guitar Concerto on. He had also owned and recorded with more than one Hauser I, an Hernandez y Aguado and a Ramirez, at least. Wasn't there a Bouchet in there somewhere as well?

My Arcangel Fernandez blanca is my favorite among all flamencas I have played. I didn't say it was "the best." Players will disagree on which guitar they like the most, depending on their way of playing, and the sound they want to get. One of my friends has a 1970-something Manuel Reyes blanca. I like my '67 Ramirez blanca better, he prefers the Reyes. They cost about the same when new, now the Reyes is worth four times as much as the Ramirez. I have played only three or four flamencas that I liked better than my Ramirez. Both the Arcangel and the Ramirez have domed tops. These tops were intentionally stressed during construction.

Damann has good reason not to dome his tops. The honeycomb structure of the Nomex he uses in the middle of his sandwich tops very strongly resists the traditional method of doming.

My college room mate is one of the pioneers of honeycomb structures, having introduced them into numerous commercial and military aircraft designs, Formula I cars, skis, etc.

At least 20 years before Damann got interested in honeycomb I helped my friend to lay out the procedure for producing a honeycomb structure with compound curvature. You can't buy stock honeycomb material with compound curvature. It has to be produced specially for the particular application.

Given the low ratio of density to bending stiffness of the wood-Nomex-wood tops Damann produces, doming is no doubt unnecessary.

RNJ



Anders Eliasson -> RE: Stress-Free Assembly (Dec. 4 2011 7:11:15)

Tom, I brace the top flat. And I´ve done so last 3 - 4 years.

Ruphus, I dont understand your inithial post, so no comments on that.[;)]



Ruphus -> RE: Stress-Free Assembly (Dec. 4 2011 12:03:25)

Hey Sherman,

Great to see you joining this forum! :O)
Welcome on board!

Guess your e-mail has changed. (Sent you a message 5 days ago, after hearing of sad news.)
-
Depending on the individual guitar, I find humidity to have rather distinct effects. ( Most of all with my Burguet AB which reacts VERY sensitive.)

When the sparkle has gone, and the guitar seems to have morphed into a sluggish something a glance on the hygrometer often shows why.
( Or when outdoor with a beater guitar: Never noticed changes after sundown when nights dampness sets in?)

Richard,

Interesting contrasts of view.

As you mention stiffening structures.
There was a technical side note less than 10 years ago.
Invention of hollow metal sheets ( steel even, I think ) whichs inner 3-dimensional grit looked a bit like conjunct stalactites, or maybe remotely like structures in natural foam, only absolutely and allround symmetrical and gracile. I think it was even on nano level.

Just from looking at it, I was so convinced of it as extremely potential light weight construction for aero- and vehicle demands that I researched for options of shares. But the inventor ( a university I believe), hadn´t contracted a manufacturer yet / set up no company.

Just tried to find something about it to show you a link, but my access seems to have been severally crippled down ( according to local friends, more so than commonly ) with too many sites now being blocked for me. ( As if unshaven cyclops were watching unpopular midgets. [&:])

Anders,

You´re right. Just looked into it, and it is very badly written indeed.

I had been claiming that Lester DeVoe must have found a way to make guitars relatively insensitive to sudden climate changes, and also staying in tune over unusually long time.
It seems to have to do with relatively stress free assembly.

Ruphus



Gimar Yestra -> RE: Stress-Free Assembly (Dec. 4 2011 12:37:24)

properly seasoned wood is (mostly) less reactive to sudden changes, and also the rate of shrinking and expanding is smaller compared to fresh(er) wood.

im sure there is much more than just that, ive played guitars wich were (altleast seemed) unaffected by humidity changes, some guitars that play well and sound well one day, and are lifeless the next day due to humidity changes.



kintla -> RE: Stress-Free Assembly (Dec. 4 2011 23:55:50)

Just to add to what Richard said, there are some luthiers who will carve the back. Jean Rompre is one that comes to mind. I don't know exactly how it works, but can guess it's about adding mass and perhaps increasing projection, but how that occurs, someone else will have to explain. And for sure this is a "stress" free back, just subject to the luthiers desire for thickness and shape.
Sherman



Page: [1]

Valid CSS!




Forum Software powered by ASP Playground Advanced Edition 2.0.5
Copyright © 2000 - 2003 ASPPlayground.NET