Cyr Custom Guitars is starting another acoustic instrument project--this time a 5-String Acoustic Bass Guitar. This bass will be very similar to the 4-string acoustic bass just completed, with a jumbo cutaway body. We'll be able to use most of the same tools that were acquired or built for the acoustic guitar project, and then used on the 4-String Acoustic Bass Guitar project. This project, like the 4-string acoustic bass, is much more of a "from-scratch" project than the Dreadnaught guitar was, in that we're going to hand-make the neck and top rather than purchase them already made up. The only things acquired already fabricated are the body sides, which are a pre-bent set of laminated mahogany jumbo guitar sides from the Martin factory. This instrument is to some degree a custom design, using essentially the same layout for top and back bracing that the dreadnought acoustic guitar used, with slight modifications to account for the Jumbo body shape and the cutaway design. In fact, this body will be nearly identical to the one built for the 4-String acoustic bass, only slightly deeper. And without the Bearclaw top.

The first picture shows the body rims in the mold with the top glued to them, and the kerfed lining has been glued on for the back: Another picture showing the sound hole and neck block area of the body. At this point, the notches need to be cut in the kerfed lining for the ends of the back braces, then it'll be ready to glue on the back: This is the back with the back center joint reinforcing strips being glued in place. The back braces are already glued at this point: Here the back is being glued to the rest of the body, using the go-bars to apply pressure all the way around the perimeter to ensure good contact between the back and the kerfed linings as the glue dries: These are the three neck blanks I cut out today. The one in front is for this acoustic bass, the next one is for a 12-string acoustic guitar, and the one in the back is for a 6-string acoustic guitar. This is the body after it came out of the form. Great news: it blew out Martha's lighter! That, according to Lynn Dudenbostel (the luthier featured in DIY Network's Handmade Music 4-part series on making a Martin D28-style guitar), is a sign the the body is a good one. The next picture shows the back of the body. Note that the channel for the backstrip still needs to be routed: Another picture of the front of the body: The body is shown again with the rabbet channels cutr for the binding and purfling. This one, like the two previous instruments I've built, will have herringbone purflings and curly maple bindings. In this picture, the first piece of binding has been glued in place, and blue tape is being used to hold it there while the Cyanoacrylate glue hardens. Now the tape has been removed: This picture shows the binding/purfling channels in the area of the cutaway: I bought a piece of really pretty Indian Rosewood on Ebay several months ago. The two pieces shown below were cut from that piece. On the left is a 4-1/2" x 8" piece of bookmatched veneer 1/16" thick that I'll use as the headstock overlay, and on the right is the bridge that will be used for this bass: These pictures show the neck after final shaping and sanding. The headstock overlay is the same one shown above. The neck itself is made from a 2-1/2" x 4" piece of African Mahogany (also known as Khaya). After I cut the neck to shape, I glued small pieces to either side of the headstock area to get the 4-inch width I needed for the headstock. I spent most of the day (Saturday June 18th) installing the bindings and purflings on the body. The bindings are curly maple (although this set is not so curly) with a B/W/B purfling built in, obtained from Stewart-MacDonald. I also inlaid the center strip in the back. To do this, I routed a 1/4" wide by 1/16" deep channel down the centerline of the back, then glued the strip in place. After it was dry, I scraped it down level with the back, then sanded it with 150 & 220-grit sandpaper. Two more pictures of the body showing the cutaway and sound hole area.:

All Pictures and Text (c) Copyright 2005 by Stephen Cyr Last updated August 16, 2005

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