Acoustic Construction Lab - Week 2

  Week two of Acoustic Construction Lab was spent focusing on bracing the guitar top. I chose to use a few pieces of Adirondack spruce that I had purchased, tilt the bandsaw table to match the end grain vertically and re-saw the spruce to get the best quartersawn stock possible. After cutting my braces slightly over-sized, I thickness sanded them to width. The Larson Brothers are known for their unique x braces consisting of a three-ply lamination, with a strip of hardwood between the spruce. I decided to use rosewood to do this for my upper transverse and x braces. Their OM sized guitars also have a top radius of 15’, so I used an edge sander jig to shape a radius on the edge of the brace that is to be glued to the top. After all my braces were radiused and cut to size, I notched and fit the x braces together. Moving right ahead, I began the gluing process using a go-bar clamping deck. I placed a dish with a 15' radius in the bottom of the deck, and bent strips of maple to apply clamping pressure and hold the brace firmly in place while letting the glue set.

  The first round of gluing installed the x brace, as well as the upper transverse brace that has a radius of 25'. After the glue had completely set, I started tapering and shaping the laminated bracing using my block plane and chisels. 

  Next I prepared my lower transverse and finger braces, by tapering and rough shaping them to size. These pieces were constructed using the Adirondack spruce.

  I used the scrap Adirondack from re-sawing my brace stock to construct small clamping cauls to fit over the finger braces, preventing them from being damaged by the wood strips used to apply the appropriate clamping pressure.

  Both lower transverse braces were also installed during round two of gluing, they were all pressed in a 15' dish and allowed two hours to set. 

  For the third round of gluing, I installed the maple bridge plate as well as the upper graft, sound hole braces and x brace cap, all made from scrap Sitka spruce pieces left from my guitar top. 

  By the time Friday rolled around, the top was completely braced and I spent a good part of my day carefully shaping the braces with a finger plane and chisels. While my guitar brace work is laid out true to the Larson Brothers design, I decided to shape the braces themselves in a more triangular approach that closer resembles the Larrivee guitar bracing. 

  During my down time waiting for the glue to set, I started to prepare my Honduras mahogany back and sides for week three. I joined my back, thickness sanded it and cut out the shape slightly over sized. I also thicknessed the sides and prepared them for bending. With every new day the pieces continue to come together and resemble a guitar more and more. 

- Justin Ness

Acoustic Construction Lab - Week 1

  One week into my acoustic guitar build and I am already finding myself dreading the weekends, i would rather keep working. Its amazing how fast the day flies by when you are building. Over the three week winter break I left my materials to acclimate in the lab environment. I chose to build a Larson Brothers Orchestra Model with a sitka spruce top, Honduras mahogany back and sides, mahogany neck with ebony fingerboard, Indian rosewood bridge and head cap veneer. 

  The first week of Acoustic Construction Lab was spent building our workstations, templates and laying out our desired neck dimensions on the blueprints. We then moved ahead with jointing and thickness sanding our tops. Having never used hot hide glue before, I decided to use it for this process. With such a small window of time before the glue begins to set, getting the two pieces placed together and clamped in under a minute and thirty seconds was a bit of a challenge. In the end it worked out just fine for me, and I am happy that I took the time to gain some experience using the hide glue as I intend to continue to use it for various glue joints throughout my build. 

  Next I cut out my body shape leaving the wood slightly oversized. I laid out the rosette in pencil, and sealed it with a coat of lacquer to help prevent end-grain splits while routing. 

  I have become comfortable with most of the powertools that we have available at the school, but a router is the one that I have the least experience with. The thought of cutting a series of perfect circle groves into my freshly joined and sanded spruce top was a little scary at first. I picked out a classic herringbone rosette and decided to add an inner ring by inlaying two purfling strips together for my desired thickness. I took my time measuring my cuts, practicing on a piece of scrap wood. When I made my final cuts, it worked out just as I had planned and the inlay was complete. 

  I used a thin bead of glue in the bottom before inlaying the rosette and ring, clamped it and let it dry. I then used scrapers to remove the excess height, bringing it down to the top level and finished by sanding it out. 

  After this process I took the top back to the router and cut out my sound hole. With the rosette completed, I started laying out the bracing on the inside of the top. I am bracing my guitar in the style of the Larson Brothers, and I made my marks by using a templet and cross referencing my blueprint. I made a cut list of dimensions and began cutting my bracing stock using quartered adirondack spruce, with a rosewood laminate for the upper transverse and X-braces. 

  Just like that, week one has come to an end. Week two will be spent bracing the top, and getting the back and sides joined and thickness sanded. It is starting to take the shape of a guitar. 

- Justin Ness