back doming question from a beginner

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wfrancis86

Posts: 36
Joined: Jun. 30 2012

back doming question from a beginner

Hello,

I posted a question about a month ago about tonewood choice and in the meantime I have made some progress on my guitar. At this point I was wondering if anyone had any suggestions for a quick way to set up a mold for my back when I go to glue in my bracing. From research it sounds like most people do dome their backs, and it seems that the doming isn't the same as the top. I was thinking I could use some pieces of thin veneer I have laying around to create the appropriate dome... Has anyone tried this? Alternative suggestions? I don't really have the time nor materials to go about making another solera for the back

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 24 2012 22:47:25

Andy Culpepper

Posts: 3023
Joined: Mar. 30 2009
From: NY, USA

RE: back doming question from a beginner (in reply to wfrancis86)

When you brace the back you're not exactly "doming" it. You're just arching it side to side with arched braces. You can glue the center reinforcement on flat, and when you glue the back onto the guitar, it will bend end-to-end to whatever shape you've put on the sides and create the dome.
So when you glue on the braces you only have to think about arching it in one direction. You can use wedges or a strip of wood about an inch wide and as long as the width of the back with a curve cut into it. Then match the braces to that curve and glue with go-bars or clamps with the curved piece underneath.

_____________________________

Andy Culpepper, luthier
http://www.andyculpepper.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 24 2012 23:13:30

wfrancis86

Posts: 36
Joined: Jun. 30 2012

RE: back doming question from a beginner (in reply to wfrancis86)

Thanks Andy for the clarification. It seems to make sense for the most part. Would you mind saying a bit more about shaping the sides? I understand that the soundboard and neck are fairly level (minus the 2mm-ish ramp in the neck) to keep tension in the top minimal. Whereas the back is actually tapered, wider in the back, more narrow at the neck. In my case, I am working from the Santos Hernandez 1933 Courtnall flamenco plan, so 96mm at the back and 87mm at the neck. But what about the arch laterally across the endblock at the bottom of the instrument, and conversely the arch at the heel/foot? The soundboard side makes sense to me, just conform it to the soundboard's dome, but were you suggesting Andy, that the sides on the backside are arched a bit laterally and then the back is pushed into this form?

Also, what would be a ballpark figure for a back dome? This is my first guitar so I really have no idea where to start. I think the Courtnall plan says top and back doming varies 2.5 to 3mm or something around there; not all that specific. My solera is domed to about 2.5mm around the bridge area at its deepest, and my neck ramp is at 2mm.

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 25 2012 15:45:21

Stephen Eden

Posts: 914
Joined: Apr. 12 2008
From: UK

RE: back doming question from a beginner (in reply to wfrancis86)

I got told off last time from the traditionalists but I will throw my two pennies into the pot anyway!

I use a 15' radiused dish to achieve a uniform dome over the whole back. You can use the dish to shape your back bars, glue your back bars and then if you line it with sand paper, use it shape the sides along with the heel and end block. Then use it to angle your linings to fit the back absolutly perfectly. This is more of a steel string technique but it does make the whole process alot easier, especially going through your first build.

You can achieve a slightly more traditional look by using a 25' dish. This gives alot less arch from end block to heel block. A 15' dish will give you more taper end to end.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 9:25:00

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: back doming question from a beginner (in reply to Stephen Eden)

quote:

ORIGINAL: SEden

I use a 15' radiused dish to achieve a uniform dome over the whole back. You can use the dish to shape your back bars, glue your back bars and then if you line it with sand paper, use it shape the sides along with the heel and end block. Then use it to angle your linings to fit the back absolutly perfectly.

Stephen,
Can you explain the using the sand paper on the back to shape the sides and heel. Do you rotate it, slide it back and forth? I'm having trouble visualizing how you do it. We use a radiused dish for the back as well but always seem to end up using clamps for gluing one brace to get a smooth dome with no ripples.

_____________________________

John Shelton - www.sheltonfarrettaguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 14:49:08

wfrancis86

Posts: 36
Joined: Jun. 30 2012

RE: back doming question from a beginner (in reply to wfrancis86)

SEden, I have read about the radius option but I don't like how this method affects the aesthetics of the side profile... it just doesn't look right for my tastes. Not saying that I have noticed much acoustically speaking, but aesthetically it's not my cup of tea. I think shimming the back and arching the bars as Andy suggested will be the easiest and cheapest option (I would have to buy more sandpaper, plywood, make the radius, etc.). Just out of curiosity how do you make a 15' or 25' radius?

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 14:59:12

Stephen Eden

Posts: 914
Joined: Apr. 12 2008
From: UK

RE: back doming question from a beginner (in reply to wfrancis86)

John. I use the dish backwards and forwards. End block to heal block. It's also a good idea to rough shape the sides first. I made a template I can pencil on to see roughly where to take off.

I'm not sure where you are coming from when you say ripple. My thoughts on this is, perhaps your dish is small and tends to cut more on the sides and less on the end blocks and heal blocks? I guess that can cause a ripple.

I made the dishes using a cradle I made for a router. the cradle has the radius I want cut into it. Then by spinning the soon to be dish and attacking it with the rounter (it does actually spin it for you) a dish is formed! a light bit of sanding and your done!

The side profile is basically the only reason some people don't like this method. I actually prefer the slightly more curvatious look it gives.

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Classical and Flamenco Guitars www.EdenGuitars.co.uk

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 15:25:44

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: back doming question from a beginner (in reply to Stephen Eden)

quote:

ORIGINAL: SEden

I'm not sure where you are coming from when you say ripple. My thoughts on this is, perhaps your dish is small and tends to cut more on the sides and less on the end blocks and heal blocks? I guess that can cause a ripple.

I understand now. We use a traditional taper rather than using the radiused dish to shape the sides, foot, etc. If we glue all the braces on using the radiused dish the braces don't conform to the desired arch from end to end making ripples in the back (caused by one brace being a little too high or low). It only takes a few minutes extra the way we do it and I like the looks. I'm sure I'd like the looks of yours as well it's just hard to change after doing it a certain way for so long.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 18:30:43

Andy Culpepper

Posts: 3023
Joined: Mar. 30 2009
From: NY, USA

RE: back doming question from a beginner (in reply to wfrancis86)

quote:

Thanks Andy for the clarification. It seems to make sense for the most part. Would you mind saying a bit more about shaping the sides? I understand that the soundboard and neck are fairly level (minus the 2mm-ish ramp in the neck) to keep tension in the top minimal. Whereas the back is actually tapered, wider in the back, more narrow at the neck. In my case, I am working from the Santos Hernandez 1933 Courtnall flamenco plan, so 96mm at the back and 87mm at the neck. But what about the arch laterally across the endblock at the bottom of the instrument, and conversely the arch at the heel/foot? The soundboard side makes sense to me, just conform it to the soundboard's dome, but were you suggesting Andy, that the sides on the backside are arched a bit laterally and then the back is pushed into this form?

Also, what would be a ballpark figure for a back dome? This is my first guitar so I really have no idea where to start. I think the Courtnall plan says top and back doming varies 2.5 to 3mm or something around there; not all that specific. My solera is domed to about 2.5mm around the bridge area at its deepest, and my neck ramp is at 2mm.

I guess everyone shapes the profile of the sides a little differently, and it's pretty hard to describe in words....
Me personally I prefer to have a spot maybe 1 inch below the waist be the highest point (not a point but a gentle curve), and have it taper down about 5-6 mm towards the foot, and have the top of the tail block be around that same level as that highest point, maybe 1 mm lower. When the back gets glued in it's arched side to side of course, and it also gets a front to back arch because of that taper towards the heel, AND because the center of the lower bout where that brace is is still going to be higher than where the back glues to the tail block even if the sides are at the same level.

I don't use a radius dish but I have radius blocks about 20" long, 2 1/4" wide and about 2" thick. I have sandpaper on those and use the concave one to sand the radius angle onto the top of the sides/linings, so the edge of the back doesn't get distorted when it's glued on.

An arch of 3 mm sounds fine, I use a 20' radius which works out to about 3 mm I think.

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http://www.andyculpepper.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 21:01:54

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: back doming question from a beginner (in reply to Stephen Eden)

quote:

I got told off last time from the traditionalists but I will throw my two pennies into the pot anyway!

Maybe you were told off by John Ray, or maybe you werent very respectfull towards those of us who do things a different than you do when you wrote:

"I Have to say I didn't particually like the more 'hit and miss' method of the more traditional way."

You wrote it on this thread which is interesting for all interested in how to prepare and fit a back of a Spanish guitar.

http://www.foroflamenco.com/tm.asp?m=187021&appid=&p=&mpage=1&key=radius%2Cdish&tmode=&smode=&s=#187167

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 21:21:59

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: back doming question from a beginner (in reply to Andy Culpepper)

quote:

ORIGINAL: deteresa1

I guess everyone shapes the profile of the sides a little differently, and it's pretty hard to describe in words....

I didn't even try to describe it having failed in previous efforts but it sounds like you do it about the same way we do.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 26 2012 21:57:28

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: back doming question from a beginner (in reply to wfrancis86)

I hate to be the turd in the punch bowl, and this is not going to be very diplomatic, but ya'll work too hard. The way to do it with out making a bunch of jigs and stuff on a first guitar is much more fundamental. Of course some people love to make jigs and the jig meisters should jig away.

All you have to do to brace a back is get a lath of flexible wood about 1/4" thick and 1" wide and 16" long.

Take the brace and lay it flat on it's side. Make a pencil mark on each end about 3mm deep. Lay the brace on a shooting board so it over hangs and then simply plane from end to end to a make along graceful curve. Aim from the middle to the mark on the end. After about four to six passes the brace will be rough curved. Tighten the throat of the plane, pull in the blade, and then pass from end to end to smooth it out. Peter Tsiorba has a curve scraped into the sole of a wooden Japanese plane. All he does is pass the plane over the brace and the curved sole causes it to cut a path and it curves the brace! Magic.

Take the back, put some glue on the brace, put the flexible lath under the back, under the brace. Clamp the brace on from the middle moving out to the ends. The lath will create surface tension under the brace which will conform to the brace and support it like a strap. Done.

No sand paper, no dishes, no wedges, just four elements: Plane, lath, clamps, skill.

You modulate the arch of the back by how you cut each brace. Time a practice tell you how you like it. The one near the heel is shallower, at the waist higher, lower bout is luthiers choice according to how you see curves.

To fit the back with a plane, the trick is to ease the ribs sloping down a tiny bit from the peak of the waist. You start a gradual slope up to the tightest curve of the waist right from where the upper bout is widest. Same in the lower bout. A few passes of the plane and it's done. This allows the ribs to reach up and meet the back in the waist where the back is higher up, but still allows a flat tapered plane form heel to tail. Another trick is to chamfer the outside edge of the ribs with pass of the plane, because you're going to cut a binding channel there and the outer edge of the rib does not have to get in the way of the back touching the liner. All you have to do is concentrate on making a seam between the back and the liner, the ribs get cut out anyway for binding.

Fitting a back with a plane is easy, the dish and the ensuing warped or wavy looking profile is considered an aberration to the classic design, in many builders opinions.

After this most straight forward way there are several ways to get more complicated, and perhaps not even faster. But if you practice the most basic way first you learn a lot more in my opinion, because you deal with the very essential problems and not muddle your thinking or eye-hand work with extra props on the stage.

There is nothing "hit and miss" about it. It's acquired skill and to dismiss classic tradition and skill for tricks with jigs is ridiculous. Jigs come after skill and the most elemental ways to doing it because to take it in the opposite order waters down the art and logic of the Spanish design.

Sorry it's not politically correct, but that is my firmly held conviction.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 1:20:21

krichards

Posts: 597
Joined: Jan. 14 2007
From: York, England

RE: back doming question from a beginner (in reply to estebanana)

quote:

There is nothing "hit and miss" about it.

I agree.
What you've described is pretty much the way I do it too.

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Kevin Richards

http://www.facebook.com/#!/kevin.richards.1048554

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 8:35:03

Stephen Eden

Posts: 914
Joined: Apr. 12 2008
From: UK

RE: back doming question from a beginner (in reply to wfrancis86)

haha yeah thats just about the response I was expecting! Cheers for that.

I don't really mind but just so you know I was not trying to be insulting or disrespectful. Just pointing out something I find easier. I have taught others to build in both methods which one do you think they found easiest?

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Classical and Flamenco Guitars www.EdenGuitars.co.uk

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 10:55:28

Andy Culpepper

Posts: 3023
Joined: Mar. 30 2009
From: NY, USA

RE: back doming question from a beginner (in reply to estebanana)

quote:

All you have to do to brace a back is get a lath of flexible wood about 1/4" thick and 1" wide and 16" long.

I like this method but it's definitely more fiddly and I personally like to glue my back braces with go-bars.

It's basically about spending a few minutes one time to make a little stick of wood vs. spending a few minutes every time to fuss with one.

The one thing I object to about your tone (and you were clearly addressing other guitar makers here, not the OP) is that you somehow are the keeper of all this great ancient wisdom and everyone else is fu*king it up.

Across time different methods evolve for doing things, some are better than old, some maybe not. That's the way it has always been done and always will be. We now have the luxury of picking the ones that appeal to us the most.

So thank you for a sharing that other approach, now cut the BS condescending tone and if you are going to respond to a beginner's question, focus on actually helping that person please...

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Andy Culpepper, luthier
http://www.andyculpepper.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 12:41:56

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: back doming question from a beginner (in reply to Andy Culpepper)

quote:

The one thing I object to about your tone (and you were clearly addressing other guitar makers here, not the OP) is that you somehow are the keeper of all this great ancient wisdom and everyone else is fu*king it up.

If you took it personally it has to do with your own perceptions of how you interpret tone.

And oh yes my delivery is performative and over the top, but I think I'm pretty generous and straight forward about showing my own process.

My interest is taking out what I think are the non intrinsic parts of the process and transmitting them as simply as possible. I think if you give a close reading to my rap I acknowledged that methods are changeable and evolve. I simply stressed learning the traditional way before going out on a tangent.

The most direct way of doing the back bracing is what I think Francis was asking for. I gave the method that one can accomplish with virtually nothing but a plane and lath. What I am trying to transmit is the idea that you can make the guitar without all the trappings, buzz words and fiddly little parts. I think that cuts through the B.S. of telling someone they need to make fixtures and jigs to accomplish something that can be done rapidly and accurately with one tool and a traditional method. After that, knock yourself out, build a factory, get CNC machine.

Guitar making always leads back to the eye, the hand, and the essential path that moves all the non intrinsic thought and action out of the way of the work. I learned this because I was trained by a seasoned pro who stressed understanding the least common denominator of each guitar making issue. If that is what you consider B.S or leading someone astray then I don't know what planet you're living on.

And I'm far from harboring the secrets or secret knowledge; the most basic ways of the process are so apparent that sometimes people miss them because they have a need to over complicate how they transmit information. I strive to cut through that type of intellectual materialism.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 16:05:45

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: back doming question from a beginner (in reply to Stephen Eden)

quote:

haha yeah thats just about the response I was expecting! Cheers for that.

I did my best to appear dogmatic and crazy. Thanks. Cheers back at you.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 17:00:54

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: back doming question from a beginner (in reply to Andy Culpepper)

quote:

The one thing I object to about your tone (and you were clearly addressing other guitar makers here, not the OP) is that you somehow are the keeper of all this great ancient wisdom and everyone else is fu*king it up.

Ahh, here I have an advantage. English is my 3rd language and Estebananas posts always end up making me confused, and I dont really understand.

SEden. I think your method is good and I have nothing against it. I dont even think its esthetically wrong. Its just different.

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Blog: http://news-from-the-workshop.blogspot.com/

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 17:21:40

Andy Culpepper

Posts: 3023
Joined: Mar. 30 2009
From: NY, USA

RE: back doming question from a beginner (in reply to estebanana)

quote:

If you took it personally it has to do with your own perceptions of how you interpret tone.

And oh yes my delivery is performative and over the top, but I think I'm pretty generous and straight forward about showing my own process.

My interest is taking out what I think are the non intrinsic parts of the process and transmitting them as simply as possible. I think if you give a close reading to my rap I acknowledged that methods are changeable and evolve. I simply stressed learning the traditional way before going out on a tangent.

The most direct way of doing the back bracing is what I think Francis was asking for. I gave the method that one can accomplish with virtually nothing but a plane and lath. What I am trying to transmit is the idea that you can make the guitar without all the trappings, buzz words and fiddly little parts. I think that cuts through the B.S. of telling someone they need to make fixtures and jigs to accomplish something that can be done rapidly and accurately with one tool and a traditional method. After that, knock yourself out, build a factory, get CNC machine.

Guitar making always leads back to the eye, the hand, and the essential path that moves all the non intrinsic thought and action out of the way of the work. I learned this because I was trained by a seasoned pro who stressed understanding the least common denominator of each guitar making issue. If that is what you consider B.S or leading someone astray then I don't know what planet you're living on.

And I'm far from harboring the secrets or secret knowledge; the most basic ways of the process are so apparent that sometimes people miss them because they have a need to over complicate how they transmit information. I strive to cut through that type of intellectual materialism.

Reasonable post.

_____________________________

Andy Culpepper, luthier
http://www.andyculpepper.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 27 2012 19:26:24

Jeff Highland

Posts: 401
Joined: Mar. 5 2010
From: Caves Beach Australia

RE: back doming question from a beginner (in reply to wfrancis86)

I'm a "disher"
Ive done it both ways, but prefer dish and go-bar.
To MY eye the aesthetics are fine, different but fine.
What I have seen, not by any members here obviously is problems with "hand fitted backs including dimples around tailblock and heel foot and a distinct recurve where the back has been forced onto flat linings.
For you guys in the USA this guy has radius dishes at a great price
http://www.cncguitarproducts.com/kmg-radius-dish-with-matching-abrasive.html

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 28 2012 3:00:34

constructordeguitarras

Posts: 1674
Joined: Jan. 29 2012
From: Seattle, Washington, USA

RE: back doming question from a beginner (in reply to wfrancis86)

I don't like spherical symmetry and it's not traditional, so I don't use those dished forms. I glue the center seam reinforcement on flat and then shape it. Then I chisel out spaces for the two lower back bars, and glue all three (curved) back bars on using 4 cam clamps per bar and one spring clamp on each end of each bar. I have bandsawn the foot so it angles down slightly towards the heel and when I am ready to fit the sides to the back I plane a slight lengthwise curve into the foot and heel, and maybe a miniscule side-to-side curve too.

I have the heel being the shallowest part of the guitar--where the sides are their narrowest. Before gluing on the back linings, I plane the back edges of the sides from about 2 inches below the waist to the heel. After gluing on the back linings, I place a straight edge across the two sides at the bottom of the foot and mark that spot on the sides. Then I measure from the inside of the soundboard to the back of the foot at that spot, and put a mark on each side at that distance from the soundboard. I plane the upper bouts of the sides down to that mark. Then I put a straight edge across the back where the bottom end of the foot will be and measure the gap. That amount (about 1/16 inch in my case) is how much the upper bouts of the sides have to be further trimmed so the foot will not make a bulge or a dimple when the back is glued on.

To establish the lengthwise curvature of the back, I plane the tailblock and sides a little so they angle towards the tail of the guitar. The highest point (since I'm working on the guitar face down; the place where the sides are the widest) is at the lower bouts' widest. I do a little more planing of the edges of the sides to make everything curve gradually.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 28 2012 5:03:13

kominak

Posts: 135
Joined: Apr. 20 2010

RE: back doming question from a beginner (in reply to estebanana)

quote:

All you have to do to brace a back is get a lath of flexible wood about 1/4" thick and 1" wide and 16" long.
Take the brace and lay it flat on it's side. Make a pencil mark on each end about 3mm deep.

That's how I did it on my first build and it worked fine and easy. Each of the 3 braces were a little different - the marks went at 3mm, 4mm and 5mm if I remember correctly (don't remember the actual order).
The fitting of the back was more complicated as I was forcing the front-back curve into the back plate and the part of the neck heel where it meets the back had to be planed under precise angle - don't know if there's a foolproof way to do it right the first time.

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Martin Kominak
Slovakia

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 28 2012 8:05:43

johnguitar

Posts: 208
Joined: Jan. 10 2006

RE: back doming question from a beginner (in reply to wfrancis86)

I was going to stay out of this one because last time I thought I might have been a bit too hard-ass. However, when I read that one method leads to dimples and another doesn't then I can't keep from commenting. If you get deformations or dimples you are doing it incorrectly. What that means to me is not that there is something wrong with the method but rather with the users knowledge of it.

John Ray

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 28 2012 12:22:59

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: back doming question from a beginner (in reply to wfrancis86)

That was very polite and correct John.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 28 2012 12:27:06

Jeff Highland

Posts: 401
Joined: Mar. 5 2010
From: Caves Beach Australia

RE: back doming question from a beginner (in reply to wfrancis86)

quote:

was going to stay out of this one because last time I thought I might have been a bit too hard-ass. However, when I read that one method leads to dimples and another doesn't then I can't keep from commenting. If you get deformations or dimples you are doing it incorrectly. What that means to me is not that there is something wrong with the method but rather with the users knowledge of it.

John Ray

That's EXACTLY what I meant, John not the method but the execution.

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 28 2012 19:56:16

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: back doming question from a beginner (in reply to johnguitar)

quote:

I was going to stay out of this one because last time I thought I might have been a bit too hard-ass. However, when I read that one method leads to dimples and another doesn't then I can't keep from commenting. If you get deformations or dimples you are doing it incorrectly. What that means to me is not that there is something wrong with the method but rather with the users knowledge of it.

John Ray

Since my posts are considered long and unreadable I will only give jaleo to posts which I like.

Asa, ole' ...toma que toma.

You should post more often your "hard ass" view is pretty interesting.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 30 2012 0:54:54

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: back doming question from a beginner (in reply to Andy Culpepper)

quote:

Reasonable post.

Thank you my lord for your magnanimous pronouncement.
Shall I muck out my lords stables or perhaps saddle my lords horse for the fox hunt?

*backs away bowing, eyes down cast*

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 30 2012 0:57:07

wfrancis86

Posts: 36
Joined: Jun. 30 2012

RE: back doming question from a beginner (in reply to wfrancis86)

Sorry to bring everyone back on topic but I'd like to report on my first attempt at arching a back. I just layed out some shims on my table which is a grid of 1/4'' squares so that everything was nice and symmetrical. A little higher at the waist area and even at the upper and lower bouts. I glued everything down with hot hide glue and evenly spaced weights because that's all I really have on hand. Looking at the back it seems to have taken up the arch I created with the shims. Its about 2.5mm at the upper and lower braces and 3.25mm at the middle brace. We'll see if it sounds good when this thing is completed. Very soon on to the back fitting/ side taper issue that was brought up. Sounds tricky but I think I get the basic idea. Thanks for all the help

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 1 2012 2:34:55

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: back doming question from a beginner (in reply to wfrancis86)

It sounds like you´ve got a well braced back.

Dont worry to much about the sides. As long as you have taper from the bottom to the heel and the back has an even curve, it´ll work fine.

Good luck.

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Blog: http://news-from-the-workshop.blogspot.com/

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 1 2012 7:47:43

stephen hill

Posts: 300
Joined: Feb. 16 2004
From: La Herradura, Granada, Spain

RE: back doming question from a beginner (in reply to wfrancis86)

Bit late in the day but I use a 15 ft dish to blue my back bars onto the back using gobars, then fit the back to my sides that have been pre profiled before bending. I use something like a 25 ft longtitudal curve from heel to bottom block rather than 15ft all round as I dont like the look of a high arched waist. A high waist can cause problems with fitting linings and purflings for some also, as well as further problems if you use the freehand router setup to cut the binding channels.
Hats off to everyone, tho including my old student and second teacher Stephen Eden as once you reach a level of experience it all works.!!

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stephen hill - granada spain
http://www.spanishguitars.co.uk

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 13 2012 20:19:15