Friday, February 6, 2015

Acoustic Constriction Lab - Week 3

   I started the week by preparing my guitar side ribs to the appropriate thickness and length for bending. I added moisture to the mahogany by running the pieces under warm water briefly before wrapping each rib individually in paper towels and tinfoil. I placed a heating blanket on the rib and sandwiched it between two spring steel sheets, placed it on the side bending mold and started the heating process. While applying heat for three minutes, I slowly pressed the center waist clamp down. Next, I bent the lower bout by slowly pulling the spring clamp, repeating the same process for the upper bout.

  After the bending was completed,  I let the rib sit in the mold and come back down to room temperature. Once cool to the touch, I reheated for another three minutes and let it cool back down again. 

  The side was now ready to be removed from the bending mold and transferred to the body mold, repeating the same process for the second rib. After placing the ribs in the mold, I clamped the cauls in place to prevent the wood from springing back and left them to sit over night. 

  The next day, I removed the ribs from the mold and trimmed the ends to size. I used mahogany to construct my neck and tail blocks, and glued them to the ribs joining the sides together. I clamped the blocks heavily and allowed the glue plenty of time to set. 

  After drying, I installed my mahogany kerfing to the inside edges of the ribs. I wrapped rubber bands around the ends of clothespins to increase the clamping pressure, and used them to firmly hold the kerfing in place while bending and gluing.

  While waiting for the kerfing to dry, I installed my center strip and braces to the back of my guitar. I used sitka spruce for the center strip, and Adirondack spruce for the back braces. I glued them using the go bar clamping deck in a 20" radius dish. Once dry, I shaped the braces with a chisel and finished them off with sandpaper to give them a clean appearance, as they will be visible through the sound hole once assembled. 

  With the weeks end, the pieces of the sound box are completed and ready to be glued together. Next week will be spent assembling the body, installing the binding, and laying out the neck and fingerboard. Step by step, its all coming together. 

- Justin Ness