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 Post subject: Re: documented build
PostPosted: Fri Dec 10, 2010 9:26 am 
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Walnut
Walnut

Joined: Wed Jun 17, 2009 5:27 pm
Posts: 7
First name: Tom
Last Name: Walters
City: Kaministiquia
State: Ontario
Zip/Postal Code: P0T1X0
Country: Canada
Focus: Build
Status: Amateur
Burton,

I am a wanna be luthier...having not completed my first guitar. All I can say about your posts is WOW! I am very intrigued with your methods, particularly the rounded neck block and your jig to sand the shape. I know you haven't got there yet but how do you round the neck to fit the guitar? If this will be shown later, I am OK with waiting for that step in the process.

Tom
:P :P :P


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 Post subject: Re: documented build
PostPosted: Fri Dec 10, 2010 10:07 am 
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Koa
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Posts: 1328
Location: United States
Hi Tom,

Yes, I will get to that eventually. I am way behind in keeping up here, I am almost to that point in the actual work. I hope to catch up soon.

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http://www.legeytinstruments.com
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 Post subject: Re: documented build
PostPosted: Sat Dec 11, 2010 11:52 pm 
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Koa
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Joined: Wed Oct 21, 2009 7:46 pm
Posts: 950
First name: Francis
Last Name: Richer
City: Montréal
State: Québec
Zip/Postal Code: H4G 2Z2
Country: Canada
Focus: Build
Status: Semi-pro
Really nice thread, thanks to share it! You have some refined methods.

About your laminate sides, I have some questions.

What does it gives you to use 2 different woods, except the weight think? Softer, harder inner sides, 3 plys with softer in middle... did you make some research about it?

Thanks!
Francis

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Francis Richer, Montréal
Les Guitares F&M Guitars


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 Post subject: Re: documented build
PostPosted: Fri Dec 17, 2010 12:49 am 
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Koa
Koa
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Joined: Sat Aug 19, 2006 1:29 am
Posts: 1328
Location: United States
Hi Francis,

I didn't really do any research. I have been using more or less whatever wood is lightest and a somewhat close color match. I assume that the reflective factor of the sides are playing a very small role in the sound (although who knows) and haven't stressed much about changing up the inner laminate. Even the weight savings is pretty minor most of the time. I just finished up a guitar with solid sides and didn't notice much difference at all with what I would expect from the doubles. The linings give it the stiffness, I think of the doubled sides as stability more than anything.

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http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 5:58 pm 
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Koa
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Posts: 1328
Location: United States
All right, lets see if I can catch up a bit here.

I have my bracing pattern all laid out and am ready to actually start gluing on the braces. The cross brace I use at the bridge and the x braces are radiused more heavily than the other braces and I shaped the x braces using my pattern forms on the router table. I laminate the cross brace to lock it in a bit before I glue it down. It is so thin I would worry about the runout if I routed the bottom and then thinned it. Here is a shot of that brace being glued up, the lower section is .04 and the top is .1.

Attachment:
BD-laminating-cross-brace.jpg


Once it is laminated and shaped I add the first 2 braces that extend past the soundhole, they are glued on flat.

Attachment:
BD-gluing-first-top-braces.jpg


Then the ends are shaped and the cross brace is glued up and butted up to them using one of my radius forms. I expect a bit of springback and use the #3 radius form here. I feel that making the radius strong right above the bridge is good insurance against it caving in so I reinforce it there specifically.

Attachment:
BD-gluing-cross-brace.jpg


These braces are then shaped and sanded as other braces will be glued on that float over them and it would be hard to shape them after. There was a node point that fell on the long parallel braces and I leave that point highest and taper from there. The x braces are next and need to be notched for each other and for the cross brace. They also fly over the long parallel braces. I cut the initial opening on the router table using my incra jig to set the angle (I think it was 91 on this guitar, most times it is wider).

Attachment:
BD-cutting-x-intersection.jpg


Then I line it up over the braces that are already down and slowly cut out the notches for the other braces. I do have a dish for my 2.5 radius and the x braces get glued in with this. Here is a shot of the upside down braces with their cutouts:

Attachment:
BD-x-brace-with-cutouts.jpg


And the x brace getting glued down. I used to be terrified of hide glue but have gotten much more used to it. I even feel okay doing the whole x brace at once. The heat gun is my friend for this procedure.

Attachment:
BD-gluing-x-brace.jpg


I add a spruce patch as my first bridge patch (it is covered with a small pernambuco patch to anchor the string balls). It is usually long grain and about .04-.05. Those get glued in using the dish as well. I want the spruce/pernambuco sandwich to be the same height and firmly butted up to the cross brace. This will allow for a smooth patch to be able to add a pickup later if it is necessary.

Attachment:
BD-bridge-patch-plate.jpg


And then the lower braces get glued in flat.

Attachment:
BD-gluing-lower-top-braces.jpg


The UTB is last and is also glued in flat. Since this guitar will have the buttresses the UTB is much less strong than it would be otherwise. I notch it to fly over the parallel braces and take the ends down very thin. It is only moderately beefy over the soundhole to strengthen that weakened spot. (sorry, I didn't get a photo of gluing it down)


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Burton
http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 6:34 pm 
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Koa
Koa
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Joined: Sat Aug 19, 2006 1:29 am
Posts: 1328
Location: United States
The back bracing is done similarly. As I don't use the dish I have to put the long radius in separately. I have different forms for each model depending on where the back taper starts. I glue this center seam reinforcement piece in long grain. I expect it to help add to the long grain stiffness of the back plate. I want the top plate and the back plate to be about a semitone apart on the finished guitar and they must be tuned very close to each other before the bridge is glued on for this to happen. Depending on how thin I take the back plate I need a little strength back from this long brace to raise the pitch to match the top. I had read somewhere how Jeff Traugott adds a back brace that flies over each back cross brace and that he does it to make it easier to tune the back. This makes sense to me, on a finished guitar shaving the cross braces will lower the pitch but it does it very slowly (in my experience at least). Changing the long grain stiffness affects it much faster. You can do this as well by sanding the back plate as it reduces the thickness of the whole plate. I would rather only have to do that a little bit to very fine tune. Deciding on how thick to make this back graft is tricky. I can guess, but until I have a bunch of data that shows me how the free plate will affect the frequency of the glued up plate I am working a bit off instinct. Eventually I hope to be able to take long grain deflection readings and use those to guide me in how thick to make the graft. Here is a shot of the graft being glued in for this guitar. I made it about .1 here as I used .13 on my last guitar of this size and it was just about correct. The mahogany I used last time was noticeably less stiff than this blackwood so I made it a bit thinner.

Attachment:
BD-back-long-brace-gluing.jpg


The back graft extends from the top of the upper bout to the 4th brace. Each cross brace is mortised over the long graft except the 4th, which butts up to it (the graft is cross grain behind that 4th brace, I want the lower bout to be loose). Here are a few shots of the other back braces being glued on. Each uses a different radius form.

Attachment:
BD-gluing-second-back-brace.jpg


Attachment:
BD-gluing-top-back-brace.jpg


Now, with both the top and back glued up with unprofiled braces I can begin to voice the plates.


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Burton
http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 6:58 pm 
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Koa
Koa
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Posts: 1328
Location: United States
The voicing process for me starts by slowly taking down the braces and recording what small changes do to the Chladni patterns. I know pretty much where I want them to be but I want to see what happens to the patterns as I make changes in certain areas. I keep a separate sheet on this until I get close to where I want to be. I am looking most at the ring+ and the horseshoe. Sometimes they are one mode and then will separate as I take it down. Other times they start off separate. In this case they started off separated. I will also look at the cross dipole once in a while to see where it is at.

Attachment:
BD-voicing-top.jpg


For this guitar the ring+ started out open at the bottom and open at the lower corners. I was able to pull it in mostly in the corners but never able to round out the lower section. I made it more of a V at the tail but never fully closed. This doesn't bother me, I had a nice clean line and it came in at about 250 which I feel is a safe number, especially considering how clean the shapes were. As I got closer to where I felt I wanted it to be I made smaller and smaller changes. I tapped at the bridge position and flexed along the x braces and across the plate and would check the chladni patterns. The tap became rounder in its tone, more fundamental maybe. I like that. As it started to sound cleaner I felt better. Eventually I felt very good about it and at that point put it aside for a few days. This is one part I don't want to rush.

The back plate is less scientific for me, I don't have a set of guidelines yet that I look for in the chladni data so I don't have places to periodically check on my progress. I see it as simpler in some ways because I can't change the long grain stiffness by shaving braces. I am really altering the cross grain and I know more or less what kind of deflection I want to feel from each brace. I always leave the 2nd brace full height, the pronounced taper of the rims puts a lot of pressure at that spot and I don't want it to flatten out there. The third and fourth get shaped the most.

After a few days I came back and decided I wasn't quite done. I made a few more changes and in the end felt better. They mostly involved the scalloping of the x braces and lower peaks. The plates ended up like this:

the top:
(shown is final bracing with cutaway piece glued on, glitter for the ring+, final chladni data (done without the cutaway piece), and final specs of brace placement and brace and plate thicknesses):

Attachment:
BD-final-top-bracing.jpg


Attachment:
BD-final-glitter-top.jpg


Attachment:
BD-final-top-chladni.jpg


Attachment:
BD-final-top-braces-and-thi.jpg


And for the back, the same photos:

Attachment:
BD-back-final-bracing.jpg


Attachment:
BD-final-chladni-back.jpg


Attachment:
BD-back-final-braces-thickn.jpg


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Burton
http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 7:18 pm 
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Koa
Koa
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Posts: 1328
Location: United States
Now that the plates are completed I can get back to the rims and do what I need to to have them ready to accept the top and back. The soundport needs to be installed next and the first step of that is to glue on a reinforcement patch. I planned for the space I would need for the port and it will be located between a vertical brace and the neck block. Considering that I have the vertical braces and my sides are doubled I would not be too concerned with forgoing the reinforcement patch. I do however like the look of a thicker wall on the soundport and that is the best reason I have for adding it. here is a shot of it being glued in. Because of the curve of the side and the vertical braces I can't glue it in flush with all the edges so I shoot for just inside all of them equally.

Attachment:
BD-soundhole-reinforcement.jpg


Once this is in I draw out the spacing on the side and mark my center point for the soundport

Attachment:
BD-x-marked-soundport.jpg


With this visual marker I then clamp my soundport jig in place to rout the opening. I then cut an opening with a forstner bit to allow access for my pattern bit in the laminate trimmer

Attachment:
BD-soundport-forstner.jpg


Then I rout the opening. Doing it this way leaves the cut in one plane which is necessary to be able to bind it cleanly.

Attachment:
BD-soundport-cut.jpg


I saved an offcut from the sides for the soundport binding and now I need to bend it into the correct shape to fit in my opening. I bend it on the pipe and fit it into the routing form. As long as it is tight there it should be fine when it is glued in.

Attachment:
BD-soundport-binding-off-be.jpg


I trim the ends until it fits in very tightly by itself and then trace the curve of the side onto the binding piece. It is necessary to bend the binding piece much wider than a typical piece if binding, I usually go for 3/8 or so. To get that tight bend I normally thin it to .05.

Attachment:
BD-pencil-mark-soundhole-bi.jpg


Attachment:
BD-soundhole-binding-marker.jpg


On the belt sander I sand to the line on the inside and outside and then I can apply the glue and tape the piece in. I find I have to double up the tape to stop it from breaking on the curved pieces. The binding piece should fit in very snugly to begin with, the tape is just make sure there are no small gaps.

Attachment:
BD-soundport-binding-taped.jpg


I totally forgot to get a close up of the finished port. It would be here if I remembered. Sorry. It came out great.


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Burton
http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 7:36 pm 
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Koa
Koa
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Joined: Sat Aug 19, 2006 1:29 am
Posts: 1328
Location: United States
Prepping the rims to accept the plates is normally pretty straight forward but it is complicated a bit by the addition of the buttresses. It starts out normal enough, I cut the openings for the brace ends to fit under the linings. For the back this means making very tight openings for the tall 2nd brace. I clamp up the front and back with equal sized blocks and see at what angle that brace wants to enter at. I then mark that line onto the linings.

Attachment:
BD-clamp-raised-for-waist-p.jpg


Attachment:
BD-marking-back-waist-pocke.jpg


I shape these openings until the second brace fits tightly in. Then I will trim the lower tongue of the neck block so that the first brace is snug against that. I cut a groove into the underside of that tongue for the long back graft to fit into, this insures everything lines up on center.

Attachment:
BD-pocket-in-neck-block.jpg


Once this fits in I cut the pockets for the ends of the 1st brace and then for the lower 2 back braces. It is important to score where your openings will be first to avoid any chipout of the pockets. I use a razor blade for this.

Attachment:
BD-score-pockets.jpg


Once they are all cut I do a test fit to make sure all is well.

Attachment:
BD-test-fit-back-with-pocke.jpg


You can see in the above photo that i removed the back linings between where the second brace will be and the next vertical brace. I didn't apply glue to this part when gluing the linings in and this section came off easily. I will be installing the supports for the buttresses in this area. That will be in the next post.

I do the same for the top as for the back. I mark and cut all of the brace pockets. At this time I also cut back the end block so that only a lining thickness is left to glue onto the plates. I use a round bit in the laminate trimmer for this so there is not a super sharp break. You can see it in this photo. (sorry it is not closer)

Attachment:
BD-test-fit-back.jpg


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Burton
http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 7:55 pm 
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Koa
Koa
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Posts: 1328
Location: United States
I showed earlier how I prep the side supports oversize to fit at about the waist area. Now I need to prepare them to accept the ends of the ball joint buttresses. This is done on the milling machine again with my fancy tilting vise. I use my initial blueprint to determine the angles that the buttresses will enter at from both directions and set the vise to those angles. I then clamp in the side support and set the offsets that the cutter will enter at.

Attachment:
BD-pillot-hole-side-support.jpg


I drill down with the router bit and flush out the opening at just oversize (I use a 1/2" bit for what will be the 3/8" buttresses). I then go in with a 3/8 bit and just put in a very little extra opening at that size. That is what the ball end will pop into and anchor in.

Attachment:
BD-side-support-holes-drill.jpg


Once one is done I set up the vise for the other side and repeat. That leaves me with 2 prepped side supports.

Attachment:
BD-side-supports-done.jpg


With my rims ready to accept them I trace on the underside where they need to be cut to fit onto the opening.

Attachment:
BD-trace-opening-on-side-su.jpg


I cut and sand to these lines and get them so they are snug in that opening. Then I can start to shape the fronts.

Attachment:
BD-side-supports-pre-shaped.jpg


I go in with my round bit again in the laminate trimmer and cut back the bottoms so the lining thickness is even with the existing linings.

Attachment:
BD-rout-lining-thicknss-sid.jpg


Once this cut is made I make sure they are snug against the vertical brace behind and to the top of the linings in the front and then shape them some more into a pleasing shape. I want some meat left and leave them thickest where the force from the buttresses will be pushing. I also want there to be a part of it glued up around the bend of the rim waist so the force is pulling on a larger area. (at least in my head this is what is happening). I like that there is a long area above the 2nd brace, I glue in supports above this brace on all my guitars anyway. This is very likely over thought out. I know it is a bit more involved than any other buttress support I have seen and it may not need to be. It was pleasing to make though and makes me feel more confident of it in the long term. Here they are being glued in.

Attachment:
BD-glue-in-side-supports.jpg


Once the glue dries I need to flush the bottoms to the rest of the linings and then open up the brace pockets again for the second brace. I know the front section is correct as it has not changed. I just need to open up the back and top to allow for a very tight fit. This is a finicky part but looks very nice if done correctly. It came out very well here.


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Burton
http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 8:13 pm 
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Koa
Koa
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Posts: 1328
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Now that my side supports are in I can really focus on getting ready to join up the plates. Right now the lower bouts of both the top and back (on the rims) are flat. I want to put a small angle on them to match what the plate naturally will flex to. To do this I will clamp down my plates and use my radius gauges to see what the plate "wants" to do. Here is the back dry clamped down and checking the radius.

Attachment:
BD-check-arches-on-back.jpg


I mark on the mold where each radius begins and the next one starts

Attachment:
BD-back-radius-marked.jpg


Then I will use my radius gauges with PSA 80 grit to just slightly shape the linings. I pencil the rims/linings and just sand until the pencil marks are gone overlapping each radius slightly and blending them all together.

Attachment:
BD-sanding-back-radius.jpg


I do the same for the top

Attachment:
BD-checking-radius-top.jpg


Once the rims are sanded I need to recheck that all the brace pockets are still deep enough. If they were very tight to begin they will need to be sanded just a bit (mostly on the outside) to still be perfect. Once I am sure then I can glue up the back!! First a shot of the final rimset and then a shot of the back being glued on

Attachment:
BD-final-rims.jpg


Attachment:
BD-back-being-glued-on-rims.jpg


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Burton
http://www.legeytinstruments.com
Brookline, MA.


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 Post subject: Re: documented build
PostPosted: Sun Dec 19, 2010 8:36 pm 
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Koa
Koa
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Location: United States
The buttresses go in next. I have been using the ball joint method and have been happy with it. I personally really don't feel confident gluing in the buttresses. I don't trust really any glue to hold forever in sheer and especially when glued to a CF rod. I thought of ways to counteract the sheer joint but none of them were easily removeable or repairable. The ball joint could easily be popped out and shimmed if need be and that sold me on it. Of course, it may never need to be and I hope that it won't. I didn't want to bank on that though.

The buttresses start with 2 3/8" hollow CF rods, 2 wood balls (insert jokes here), and 4 ebony inserts milled to fit into the rod ends.

Attachment:
BD-buttress-parts.jpg


The ebony inserts are glued into the ends of the CF rods with medium CA and then shaped to a have a round end. I make them as close to the end of a 3/8 ball as I can first on the sander and then by hand. I ALWAYS wear gloves and a respirator when sanding or cutting CF. I really hate it, if any gets on your skin it feels like fiberglass with that gross itchy feeling.

Attachment:
BD-glue-inserts-in-rods.jpg


Attachment:
BD-ball-ends-shaped.jpg


The wood balls are center drilled to 3/8 about halfway through on the drill press.

Attachment:
BD-hole-in-ball.jpg


With the rods oversize I insert them into the side supports and check to see whereabout they should be cut on the other end to be short of the openings in the neck block. I will then cut them back. To cut the CF rods I use a diamond wheel in the dremel and have the shopvac right next to the cut.

Attachment:
BD-cutting-CF-rods.jpg


Then I insert the end of the CF rod into the wooden ball and check to see how it fits into the neck block opening. I want it to be just about 1/8 or so short of fitting in tightly. Once I have that right I add the other 2 ebony inserts to the other end of the CF rods and glue them in. Then I will slowly sand them back until I can force the finished buttress into the side supports. You can feel it click into place as it enters the little 3/8 opening I milled into the support opening. You want it to be very tight. You should be able to twist the rod a little but you can feel when it is in there tightly. Many times when it clicks in you can feel a little play. On these I did have to shim them a bit right away. I don't worry about this. It lets me know I am sneaking up on being perfectly fit. Here is one installed:

Attachment:
BD-buttress-installed.jpg


And a shot at the neck block end:

Attachment:
BD-both-buttress-balls-in.jpg


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 Post subject: Re: documented build
PostPosted: Mon Dec 20, 2010 12:34 am 
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Koa
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With the buttresses in now I am ready to glue on the top and get the box looking correct. This is done with clamps, the same as the back.

Attachment:
BD-gluing-top-on-rims.jpg


And then out of the mold the body is looking good.

Attachment:
BD-assembled-rough-body.jpg


Attachment:
BD-assembled-rough-body-bac.jpg


After clean up I can run a few more tests and then move on to binding.


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 Post subject: Re: documented build
PostPosted: Mon Dec 20, 2010 12:44 am 
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Koa
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I also made a trip over to my friend Steve's shop to pick up the pearl that he cut for the headstock. He does absolutely excellent quality work on his CNC machine, I couldn't recommend him any higher. His guitars are equally amazing, if you get a chance check out his site, http://www.spodarykguitars.com. There are some great Youtube videos of his guitars being played. I was lucky to babysit the little koa one at my house for a while and loved playing it while I had it.

Here is Steve's CNC machine at his shop:

Attachment:
BD-Steve-CNC.jpg


He cut the pearl that I had positioned on the MDF and it all went well. I will be able to just drop it in water and it will let the hide glue go and the pearl will float off. He also cut the pocket for me in the headstock I bound.

Attachment:
BD-pearl-cut-at-steves.jpg


Once I got everything home I pressed the pearl into the pocket and it fit perfectly, it is always very satisfying.

Attachment:
BD-logo-pressed-in.jpg


I flooded the area with thin CA and let it dry by itself

Attachment:
BD-logo-CA-flood.jpg


Then I ran it through the sander, wiped some naptha on it for a sec and imagined how it will look with finish.

Attachment:
BD-hdstck-with-logo.jpg


Thanks again Steve!


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 Post subject: Re: documented build
PostPosted: Mon Dec 20, 2010 8:06 am 
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Cocobolo
Cocobolo

Joined: Mon Jan 28, 2008 11:24 am
Posts: 115
Location: Cleveland OH
Unreal! Honestly. Unreal!

It's great that you are documenting this so well since it is all hidden now...

You love what you do and it shows.

Thanks for sharing. I'm still watching and learning!

Best,
_Mike


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 Post subject: Re: documented build
PostPosted: Thu Jan 13, 2011 2:29 pm 
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Cocobolo
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Posts: 213
Location: Meredosia, IL 62665
Burton,

I am certainly enjoying your build. Thanks for sharing it. Is your top bracing your design and how long have you used it? I suspect, with your documentation methods, you are pretty confident in the top bracing. The whole interior of the box is so carefully constructed and visually attractive.

When complete, could you make the whole build available, less our forum comments as a download for reference to we less skilled artisans?

Thanks again.

Danny R. Little


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 Post subject: Re: documented build
PostPosted: Thu Jan 13, 2011 8:44 pm 
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Koa
Koa
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Thanks for the encouragement Mike and Danny,

About the top bracing, it is usually a little different each time, at least behind the bridge. I am confident enough of it, I know it will hold up and I know this one will sound good. I still find that each build for me opens up new ideas and I want to incorporate some of those into each subsequent guitar. My worries have shifted from "will it hold up? or "will it sound good?" to "will that change do what I think it will?". The other parts in the box are usually more concrete, the linings are always done the same etc... but truthfully, I am not confident that anything may be the same 5 guitars from now. I even look back 5 guitars ago and see some major differences. I thought those older ones were excellent too but I liked what the small differences did and moved towards those changes.

In terms of making this available as a download, I don't know. In the same vein, I didn't mean it as a huge how-to, although I see that it certainly reads like that now. I think I got carried away at first and felt I had to keep it up. I am also stuck in a tutorial writing style and that doesn't help. I meant it more as a "this is where I am at now" type of thing. Like above, I don't expect to be doing all these same things in the future the same way and it isn't traditional enough to be a truly applicable how-to for most people. I hadn't really considered making it available past its archiving here but my last tutorial was also prepared for the Newenglandluthiers.org website and edited without the comments. If I do get it together to collate it will most likely be there.

There are sections I would like to re-do also (already!). I am still lagging behind, I have the bevel cutaway done and while working on it realized there was a better way to go about it. This document won't show the new way but I have wanted to prep a bevel cutaway tutorial and maybe I will do one specific to that once I incorporate some of the new ideas and round them out. That has happened a lot, the documenting has been very helpful in examining my processes. More than once I started to do something and then realized I was going to have to show everyone how I was going to do it and stopped to rethink it a bit. Not because the way I had been doing it wasn't working but more that I could see it wasn't the best way I could do it and didn't want to have to explain that. I am not sure if I would have taken the time to adjust a jig or rebuild something had I not been thinking about showing it. It has been an interesting process for sure and in the end very helpful for me creatively. I always think it is funny that something that feels so much like work (the photographing, documenting and explaining process) can yield such benefits but it usually like that. It is nice to feel that hard work (or at least what feels like hard work) pays off.

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 Post subject: Re: documented build
PostPosted: Tue Jan 18, 2011 7:47 pm 
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Burton LeGeyt wrote:
... I think I got carried away at first and felt I had to keep it up. I am also stuck in a tutorial writing style and that doesn't help. I meant it more as a "this is where I am at now" type of thing. Like above, I don't expect to be doing all these same things in the future the same way and it isn't traditional enough to be a truly applicable how-to for most people. I hadn't really considered making it available past its archiving here but my last tutorial was also prepared for the Newenglandluthiers.org website and edited without the comments. If I do get it together to collate it will most likely be there.

There are sections I would like to re-do also (already!). I am still lagging behind, I have the bevel cutaway done and while working on it realized there was a better way to go about it. This document won't show the new way but I have wanted to prep a bevel cutaway tutorial and maybe I will do one specific to that once I incorporate some of the new ideas and round them out. That has happened a lot, the documenting has been very helpful in examining my processes. More than once I started to do something and then realized I was going to have to show everyone how I was going to do it and stopped to rethink it a bit. Not because the way I had been doing it wasn't working but more that I could see it wasn't the best way I could do it and didn't want to have to explain that. I am not sure if I would have taken the time to adjust a jig or rebuild something had I not been thinking about showing it. It has been an interesting process for sure and in the end very helpful for me creatively. I always think it is funny that something that feels so much like work (the photographing, documenting and explaining process) can yield such benefits but it usually like that. It is nice to feel that hard work (or at least what feels like hard work) pays off.


Burton, As mentioned previously, I have enjoyed your documented build.

I think that when we teach something it forces us to think through every step in detail which helps us clarify what and why we are doing what we are doing. This help us as much as the "students". I believe that you are experienceing this "teaching" benefit even though you started out just to "document".


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 Post subject: Re: documented build
PostPosted: Tue Mar 15, 2011 6:28 pm 
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Sorry for the long delay here, I got busy and needed to push through a few things, this got dent to the corner for a while but I hope to get everything down to finish it out. At this point the guitar is done! Lets rewind a bit though and find where I left off...

Once the body is together I want to check it and see what frequencies the top and back are in relation to each other. I want them to be very close and to end up almost exactly the same before it goes out for finish. I set up my Chladni testing unit again and run the top and back:

Attachment:
BD-Chladni-closed-box-top.jpg


For the back it needs to be elevated a bit to get a proper reading. I do not know why. I learned this from Mark Blanchard's talk from 2007.

Attachment:
BD-chladni-closed-box-back.jpg


I look for the lower ring modes on the top and back, once they are glued up they are by far the most powerful modes. In this case they came in almost exactly the same, at 205 Hz. It seems a tiny bit high but it is a small guitar and I did brace it a bit heavier then usual so I am not too worried. I do feel good that I braced the back correctly based on my last few guitars, I can trust that a bit more in the future.

With that testing out of the way and in a good spot I can move on to the binding and purfling.

The first thing I do is too apply some shellac to the top. I know from working this spruce already that it is a bit stringy. I would put the shellac on anyway but especially so when the spruce is like this as it is liable to pull up some fibers when removing the tape.

Attachment:
BD-apply-shellac-to-top.jpg


I also need to sand the sides and back clean from all the glue residue that has been on there since the sides were glued to their doubles. I want the sides to be as level as possible and if there are any bumps in the bends I want to sand those out now, before I cut the binding channels as the offset will ride along the side. I use a hard block with PSA sandpaper to sand the sides. Once done I am left with this:

Attachment:
BD-clean-prebind-back.jpg


I have been using 2 different binding jigs both based off of the same principle. The first uses a full size PC 690 router and lets me use a 1/2" shank router bit. I use this jig to hog out 90% of the channel. The jig looks like this:

Attachment:
BD-big-binding-jig.jpg


The middle piece rides up and down in rails and you can shim it using a piece of the binding to lower it that much. You can see the little piece of wood stuck in the side. I never got it perfect enough to do the whole thing this way but I can get it very close. The initial cuts looked like this off of this machine:

Attachment:
BD-initial-binding-cut.jpg


Attachment:
BD-initial-binding-cut-clos.jpg


You can see I did not cut all the way through the brace end. I will finish that bit off in my handheld jig when I enlarge the pockets slightly.


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 Post subject: Re: documented build
PostPosted: Tue Mar 15, 2011 7:18 pm 
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My secondary binding router jig is a handheld one and also uses a piece of binding (or similar thicknessed piece) to set the offset for the cut. Here is a photo of it:

Attachment:
binding-jig-2.jpg


I use this to enlarge the binding ledges to their full size. Then I put a piece of the purfling in behind the shim used to set the binding ledge, raise the bit to the correct height and go in to cut the purfling ledges. Here is a piece of purfling in the jig and then shots of the purfling ledges cut:

Attachment:
BD-purfling-in-binding-jig.jpg


Attachment:
BD-purfling-channels-cut.jpg


Attachment:
BD-back-purf-channels-cut.jpg


Once these are cut I run a razor blade along their edges and make sure they are smooth. If I find any discrepencies I need to take care of it here. Usually there is a small one in one of the waist areas and I need to make sure it is even through there. The next thing to cut is the purfling channel for the bevel cutaway. I want to do this first and then shape the angle to the purfling line. I make a master jig of the shape which references off of the center line and top of the guitar:

Attachment:
BD-cutaway-purf-jig.jpg


I use a small end mill slightly larger than my purfling will be, I will show why a bit later. I just let the upper part of the bit ride against the MDF and try to go at an even speed to avoid burning. It is not ideal but it works very well. Once cut the channel looks like this:

Attachment:
BD-cutaway-channel-cut.jpg


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 Post subject: Re: documented build
PostPosted: Tue Mar 15, 2011 7:38 pm 
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I have been using a boxed end graft and backstrip so I need to "box" them in now before installing the binding and purfling. I'll start by cutting out the end graft channel to match the thickness of the backstrip.

Attachment:
BD-end-graft-channel-cut.jpg


Then I will size my end graft to make a tight fit and add the purfling onto both sides.

Attachment:
BD-end-graft-install.jpg


Once it has dried in place and I sand it flush with the sides I will flush the top and bottom to be right at the binding channel. To box it in I need to remove a purflings worth of the graft so I will tape off exactly where I want that to start:

Attachment:
BD-taping-off-purf-spot-end.jpg


Then I will start the opening by first making the 2 miter cuts I will need. I have had the best luck using razor blades for this, I prefer the smaller size for these exact cuts.

Attachment:
BD-first-miter-cuts-end-gra.jpg


Once I have removed the rest of the opening I am left with this:

Attachment:
BD-end-graft-box-opening-cu.jpg


With this done I can cut the corresponding sized piece from my excess purfling and take my time getting it exact. Once perfect I glue it in making sure to give the right pressure to seat it well. If it is not already the right size (height) for the miters to be flush I will cut them down so I am sure they are truly flush. It is more of an issue when both miters (or butt joints) are oversize but I still like them to be almost exactly the right size when I glue them in:

Attachment:
BD-press-in-end-graft-piece.jpg


With both done I have a nice boxed graft.

Attachment:
BD-end-graft-boxed.jpg


I didn't photograph boxing the backstrip but I do it the same way. With the end graft and backstrip all done I can move on to installing the purfling.


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 Post subject: Re: documented build
PostPosted: Wed Mar 16, 2011 7:36 pm 
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My purfling was all glued up and ripped from the sheets I made(shown at the beginning of this thread). To get them ready for install here I will put a simple bend in for the waist and a little bit of work for both bouts. The thinner purfs (.06 or less) could most likely go in dry but it is easier to have a little help right off the bat. FWIW I have never had them delaminate during the bending process, it usually goes fast and easy. Here are the back purflings pre-bent and ready to install:

Attachment:
BD-pre-bent-back-purfling.jpg


I install these with brush on CA and just hold them in place as they dry. I usually do 3-4 inches at a time. It takes about 15 minutes to do the whole back this way.

Attachment:
BD-installing-back-purfs.jpg


The butt joint is a little critical, it is hard to hide when it is not really tight. I cut back both sides so they are level to the top and reduce them very very slowly until they fit together very snugly and then lock them in.

Attachment:
BD-prepping-back-purf-butt-.jpg


For the top purflings I bend them a bit as well. The wider they are the more I pre-bend them. These are not so bad so I did them only a bit more than the back purflings. I install the top purflings with teflon strips and surgical tubing. I am scared of using CA on the top and I really want them locked in their cavity as tightly as possible as any gap shows much more against the spruce. Here are the purfs and the teflon strips:

Attachment:
BD-top-purfs-prepped-teflon.jpg


I run some white glue along 3/4 of the purfling channel and loosely tape in the purflings with the teflon acting as the binding. Then I wrap the whole thing in surgical tubing to really press it in. I start at the waist and move out from there.

Attachment:
BD-top-purfs-wrapped-teflon.jpg


I copied this from seeing some shots of Olson's methods, I really like it. I no longer stress out about the purfling install. I haven't had a gap since I started doing it this way. The same care is taken with the butt joint, I cut it down to make sure it is tight and lock it in again with the teflon.

Attachment:
BD-top-purfs-butt-join-cut-.jpg


Attachment:
BD-top-purfs-butt-join-w-te.jpg


And out of the glue up it looks good

Attachment:
BD-top-purf-butt-join-glued.jpg


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 Post subject: Re: documented build
PostPosted: Wed Mar 16, 2011 9:11 pm 
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For the purfling on the cutaway I need to add one layer before I install it. I cut the channel a bit larger than the purfling I installed on the top and now I need to account for that difference with a small strip of the same wood I will be using for the cutaway. In this case I will be veneering the cutaway with the same wood as the back and sides. So I cut a small strip and thicknessed it so that when glued to the top purfling it will fit snugly in the channel cut for the cutaway. Here is a shot of the top purfling and the new thinned layer:

Attachment:
BD-slice-cut-for-cut-purf.jpg


and here it is being added to make one strip

Attachment:
BD-lam-thin-strip-for-cut.jpg


The purflings extend past the opening for the cutaway channel and need to be cut back and mitered for the purfling strip to fit in:

Attachment:
BD-cutaway-side-miter.jpg


The purfling strip gets bent to the exact shape of the cutaway and then the end gets cut back to make a tight miter. This is the dry fit:

Attachment:
BD-cutaway-purfs-dry-fit.jpg


When I am sure it is good I will lock down the ends making sure the middle is pressed tightly in place and after shellacing the channel heavily I will use thin CA to lock the purfling strip down. This is one area I really want to see everything in place before gluing in so I do use the CA here on the top but I am wary of it each time.

Attachment:
BD-installing-cutaway-purfs.jpg


Once that is in and leveled to the top I can work on the other miter. This one is easier. One end will be covered by the neck pocket and it is more of a normal 90 degree angle, not a acute one like the miter on the side.

Attachment:
BD-cutaway-miter-at-neck.jpg


This one gets the white glue.

Attachment:
BD-cutaway-miter-teflon.jpg


And when done it looks like so (ignore the binding, I am getting a bit ahead of myself here):

Attachment:
BD-cutaway-purfs-in.jpg


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 Post subject: Re: documented build
PostPosted: Thu Mar 17, 2011 8:47 am 
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Burton,
I love how you do your purfling glue ups. Where do you get your teflon strips that size? I think that might be a method I might like to adopt.

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 Post subject: Re: documented build
PostPosted: Thu Mar 17, 2011 9:19 am 
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HI Chris,

I bought a sheet from the local plastics place and sliced those off of it. It was an offcut for them, I think 1/8x6x36. I have ended up using it for a bunch of stuff.

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