# Luthiery Fun



## Chinitorama (May 14, 2009)

*Getting Started*

After years of dreaming about it I've started to build a guitar. As I've mentioned elsewhere on LJs I plan to do most of it in a spare condo bedroom. So far I'm still wrestling with the problem of humidity control as I can't keep my workspace closed from the rest my home and I haven't bought a dehumidifier yet. Any suggestions out there?

For now, my intent is to focus on aspects of luthiery which aren't as effected by moisture. As things progress I'll find a way to justify getting all the climate control gear.

So here goes…


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## craftsman on the lake (Dec 27, 2008)

Chinitorama said:


> *Getting Started*
> 
> After years of dreaming about it I've started to build a guitar. As I've mentioned elsewhere on LJs I plan to do most of it in a spare condo bedroom. So far I'm still wrestling with the problem of humidity control as I can't keep my workspace closed from the rest my home and I haven't bought a dehumidifier yet. Any suggestions out there?
> 
> ...


Another way to get the humidity down on guitar wood is to make a box about 2×2 ft and about 10" thick out of plywood. Mount a light socket inside and put in a 60 watt bulb. Be sure it's away from the sides so a fire doesn't start. Heat build-up in the box should cause most moisture to leave. After the top and back are glued to the sides it doesn't matter as much which is good because it doesn't fit in the box after that anyway.
This is the method I used when I first began making acoustic instruments.


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## Chinitorama (May 14, 2009)

*Rosette*

The top was glued up as any other panel would be, only thinner at about 3mm. The material was a lucky find at a local lumberyard. Nicely quartered cedar is easy to find here in BC. Unless noted otherwise, Titebond 3 is the glue used.

Rosettes in classical/flamenco guitars are most often mosaic and herringbone inlay. I love the look of traditional rosettes, but they are complex to make from scratch. Mass-produced rosettes can be purchased from most of the big luthier supply houses. As I'm impatient and wanted to test some of my own design ideas, I decided to make my rosette as a veneer inlay bordered by black stringing.








Here's my circle cutter and two jig/clamping cauls. The cutting tool is an adjustable blade held in a stock which pivots on a 1/4 inch pin. 








My choice for the body of the veneer is yellow cedar a few mm thick. The black veneer edges are glued using pushpins to apply clamping pressure. 








Masking tape clamps the inner veneer stringing after the center is cut out. The inlay is planed and scraped flat on both sides.








The shape of the guitar body is known as the plantilla and is traced onto the top plate. A 1/4 inch hole is drilled at the center of what will be the sound hole to act as a pivot for the circle cutter. 








After the borders for the rosette channels are cut I use my router plane to excavate it to a consistent depth. In this case I went for a little more than half my inlay's thickness, about 1.5 mm.








After a test fit I glue in the rosette. Moisture makes things swell a bit so a small drawer knob is used as a burnisher to seat the inlay in the channel.








After everything's dry the rosette is planed and scraped flush. The gap cut in the inlay is where a section is cut out to make the rosette more flexible. It will be filled with a keystone shaped plug which will be covered by the fretboard.


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## stefang (Apr 9, 2009)

Chinitorama said:


> *Rosette*
> 
> The top was glued up as any other panel would be, only thinner at about 3mm. The material was a lucky find at a local lumberyard. Nicely quartered cedar is easy to find here in BC. Unless noted otherwise, Titebond 3 is the glue used.
> 
> ...


That was a very good blog and it demonstrates a lot of handwork skill as well. I couldn't help wondering if your circle cutter is a commercial tool or shop made. If it is shop made, a blog showing how to make one would sure be interesting. We haven't seen much practical luthiery here on LJ.


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## Chinitorama (May 14, 2009)

Chinitorama said:


> *Rosette*
> 
> The top was glued up as any other panel would be, only thinner at about 3mm. The material was a lucky find at a local lumberyard. Nicely quartered cedar is easy to find here in BC. Unless noted otherwise, Titebond 3 is the glue used.
> 
> ...


Hi Stefang,

Thanks for the kind words. This is my first instructional-type blog and I'm glad people can get something out of it.

Wish I could say I made the circle cutter, but it came from Luthier's Mercantile. They make some pretty sweet tools specifically for guitar makers out of anodized aluminum and steel with micro adjusters and Hock blades. The circle cutter comes with a nice pivot pin of polished steel, but any broken 1/4" drill or router bit would do.

-J.


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## Chinitorama (May 14, 2009)

Chinitorama said:


> *Rosette*
> 
> The top was glued up as any other panel would be, only thinner at about 3mm. The material was a lucky find at a local lumberyard. Nicely quartered cedar is easy to find here in BC. Unless noted otherwise, Titebond 3 is the glue used.
> 
> ...


Ah, I should clarify about the black veneer. The material isn't actually wood but a fiber composite that is also sold by LMI. Comes in a variety of colours. Planes like wood but no changes in grain direction or colour inconsistencies to worry about. The stuff is super strong so it won't snap either when cut into narrow strips. This toughness comes at a cost tho as it's a bear to cut into stringing. I have a sweet cutting gauge I purchased for this purpose and I still had to take multiple passes from both sides of the sheet. In the end the last bit was cut with a craft knife and a straight edge. I used a special scraping tool made out of a plane iron to clean the edges up afterwards. I'll post a pic to show how that works soon.

-J.


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## Chinitorama (May 14, 2009)

*Solera *

Probably the most important fixture in the guitar building process is the Solera. This jig is used to establish the arch in the guitar's top as well as the necessary angle of the neck in relation to the top. Basically it's a guitar-shaped board with sections carved away to facilitate various shaping and assembly processes. A shaped clamping caul more or less.

I've read about these fixtures being made of mdf and solid wood but I chose 3/4 fir plywood. A previous attempt on birch ply ended badly as I discovered large voids just under the surface. While not as fine grained, the fir ply has much thicker veneers so I shouldn't have any problems when removing material in the area of the lower bout.

Sorry about the poor resolution, I forgot my camera and had to use my phone. Here's a pic of everything I needed: templates, scraper, flexible sanding block and radius plane. I also used an orbital sander in the final stages. 








First I cut out the solera on my bandsaw. The shape of a guitar's body is called the plantilla and can vary quite a bit from maker to maker. I'll be using a plantilla taken from the guitars of Manuel Reyes. Roughly four inches of material is left outside the line traced around my body template. Add-ons for assembling the body are attached to this border to hold the sides during assembly of the sound box. The steel pin marks the center of the sound hole and will eventually be threaded for a caul which holds the top in place while gluing on braces and sides. I intend to mount a go-bar rig.



Next the area of the solera that will support the lower bout must be hollowed to accept the dome of the soundboard. According to the plans I purchased this doming should be roughly 2 mm. I'm not sure how much spring back to expect so I may go back later and take out more material when I am actually ready to start gluing in the braces.

Taking my time I planed and scraped a pear-shaped dish in the plywood. Frequent checks with a template ensured the recessed area was uniform and symmetrical across the area just in front of where the bridge will be. This point is also the deepest part of the arch and placing it in front of the bridge should help resist the tension placed on the top when the guitar is strung up.

Although the arch is slight, placing the straight edge of the template across the same area shows that it's definitely not flat.

More pics soon as I refine the surfaces and get ready for the next step!

-J.


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## CampD (Nov 8, 2008)

Chinitorama said:


> *Solera *
> 
> Probably the most important fixture in the guitar building process is the Solera. This jig is used to establish the arch in the guitar's top as well as the necessary angle of the neck in relation to the top. Basically it's a guitar-shaped board with sections carved away to facilitate various shaping and assembly processes. A shaped clamping caul more or less.
> 
> ...


I'll be watching!


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## stefang (Apr 9, 2009)

Chinitorama said:


> *Solera *
> 
> Probably the most important fixture in the guitar building process is the Solera. This jig is used to establish the arch in the guitar's top as well as the necessary angle of the neck in relation to the top. Basically it's a guitar-shaped board with sections carved away to facilitate various shaping and assembly processes. A shaped clamping caul more or less.
> 
> ...


I have been thinking of building a guitar for some time now. I'm still not sure if I want to do it, so it will be fun watching your blog on the build of this one.


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## Chinitorama (May 14, 2009)

*Bending the Sides Part 1*

Still without a climate controlled work room, I'll continue through the list of tasks that can be done without a dehumidifier. Next up is one of the steps that seems to mystify a lot of non-guitar types: side bending.

There are many different approaches to this task ranging from hi-tech electric blankets to boiling. My method is based on conversations with luthier friends and guitar geek research. It's also probably one of the simplest to set up without spending a ton on expensive or complicated tooling.

My background is as a flamenco guitarist, so I chose Canadian yellow cedar for my back and sides. Traditional flamenco guitars use European cypress, and yellow cedar is a closely related species. The pieces are perfectly quarter sawn and thinned to 2.5 mm. Once the guitar is assembled and sanded this will be reduced further to approximately 2 mm.

Commercially produced bending irons are easily sourced from several luthiery supply houses, complete with built in temperature control. These units work very well and are found in guitar shops the world over. They are, however, like most specialty tools quite expensive.

For a lot less money you can easily make one. Here's a shot of mine:









The heat is provided by an electric barbecue starter inside an aluminum pipe. 









The pipe was purchased from a scrap yard and squished in their hydraulic press. Not only does modifying the pipe's cross section make room for the starter's heating element, it also provides a surface with multiple radii to accommodate the changing curves of a guitar's body. A router speed control provides easy temperature adjustment. The spray bottle contains water to mist the sides in order to produce the necessary steam. Total cost to assemble came to about $75, and the router control is useful for…um, well…routing.

Many luthiers advocate soaking the side wood prior to bending. Others say it's unnecessary. I chose to bend the sides dry save for a generous spritzing from the spray bottle. In Part 2 of this episode I'll run through the actual shaping of the curves and how to go from this:









To this:

















-Jake.


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## BigTiny (Jun 29, 2010)

Chinitorama said:


> *Bending the Sides Part 1*
> 
> Still without a climate controlled work room, I'll continue through the list of tasks that can be done without a dehumidifier. Next up is one of the steps that seems to mystify a lot of non-guitar types: side bending.
> 
> ...


You're a flamenco guitarist? I'd dearly *love *to be able to play that well.

Nice looking job so far.


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## Chinitorama (May 14, 2009)

*Bending the Sides Part 2*

Here's a shot of my bookmatched sides ready to be bent:









Many luthiers shape an edge on each side with a compound curve before bending. This aids fitting the back and makes it a good idea to label everything before you get started. I'll shape this edge after bending, but want to ensure the grain is as symmetrical as possible from bass to treble sides of the finished instrument.
Bending begins at the waist and I've marked this location approximately 14" from what will be the neck end.









With my bending iron plugged in, the dial is turned to the middle setting. Yellow cedar is pale in colour so I have to be more aware of scorching than if I were using a dark timber such as rosewood. Therefore I'm going to lay off higher heat until I've had more practice. Even at a lower setting the heating element inside the pipe gets red hot. It's hot enough to bend when water pings off the surface rather than sizzles.

















The side is given a generous spray of water and held against the hot pipe. Steady gentle pressure is applied until I feel the wood become flexible. This has been described as feeling the wood "relax". Once the wood starts to give way, I apply more pressure whilst listening for the sound made by moisture evaporating on the hot metal. To avoid scorching, I use the spray bottle to keep the surface touching metal moist and keep the wood moving.








Any kinks can be corrected by selective heating on the opposite face.









I check the bend against a mold made of laminated mdf. When satisfied with the fit, I move on to the lower bout.
























More checking against the mold. More bending.

















After bending the upper and lower bouts I clamp the side into the mold to let the side cool off and dry out. As you can see, the side has been over bent at the ends. This is to allow for spring back as the wood tries to straighten itself out when removed from the bending iron. I again begin at the waist and realize very quickly that I should have made my mold much deeper. I was impatient and tired of large clouds of mdf dust. The clamps fit but it's awkward.

I make it work and set the package aside to settle. After a day or two I'll unclamp the side and touch up any irregularities until the side fits the mold perfectly without the need of clamps.

















I must admit I was expecting this stage of the guitar build to be more difficult. Yellow cedar bends easily though, and tests on scrap wood helped me get a feel for the process. Enough of the test pieces snapped for me to recognize when I might be pushing the bend too hard.

All in all, I think things went rather well.

-Jake.


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## Brit (Aug 14, 2010)

Chinitorama said:


> *Bending the Sides Part 2*
> 
> Here's a shot of my bookmatched sides ready to be bent:
> 
> ...


Hi Jake,

Thanks for documenting the process. I played guitar for about 27 years, before I had to sell me collection to finance my house restoration. One day when I've honed my woodworking skill enough, I hope to build my own accoustic.

I like your home made bending iron, I might have to steal that when the time comes. How long do you have to leave the sides clamped in the form so they retain their shape?


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## SPalm (Oct 9, 2007)

Chinitorama said:


> *Bending the Sides Part 2*
> 
> Here's a shot of my bookmatched sides ready to be bent:
> 
> ...


That is so cool. I am watching with my mouth open. You make it seem doable.

Thanks for the blog,
Steve


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## RonPeters (Jul 7, 2010)

Chinitorama said:


> *Bending the Sides Part 2*
> 
> Here's a shot of my bookmatched sides ready to be bent:
> 
> ...


Yes, very cool. On a violin we use a bending strap to pull the wood against the iron. It keeps me from burning my fingers! Also helps distribute the heat on the other side.

Thanks for showing your progress and process.


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## Chinitorama (May 14, 2009)

Chinitorama said:


> *Bending the Sides Part 2*
> 
> Here's a shot of my bookmatched sides ready to be bent:
> 
> ...


Hi all,

Notottoman, a two part mold isn't needed for this kind of side bending. I have seen them used tho when making laminated sides. Some builders veneer the inside of guitar sides to make them more rigid. This in theory isolates the top making it resonate differently to produce a bigger sound.

Brit, I think it varies as to how long the sides need to sit in the mold. I'm using the approach of leaving them in till I intend to glue them to anything. The bending iron design really works and is used by a lot of luthiers. Like I said in the blog, super cheap and the parts can be taken off and used for other purposes between bends.

My plan is to show building the neck in Episode 6.

Thanks for the interest and support!

-Jake.


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