We now need to attach the Kerfing to the sides of the guitar. The Kerfing is those tiny little blocks you see when you look inside the body of the guitar. If you have a Cole-Clarke you wont find these!
Once the Glue has dried, the Kerfing needs to be shaped. The Kerfing is shaped using a flat spokeshave or plane at a 15 degree angle sloping down towards the outside of the guitar. The shaping should go level with the sides of the guitar. Finish by sanding the shaved area using 120 -180 sandpaper, to maintain the correct radius angle place fingers or a small block of similar depth under the side opposite where the sanding is taking place as shown. Or, you could use a radiussed dish which gives a far better result although it is a bit more work!
We need to chisel out (or use a dremel- as I do) a cavity for the braces to sit in. This ensures a tight lasting fit and gives strength to the body of the guitar. The braces will also need to be trimmed to size during this process.
A specially prepared Pencil is slipped into the gap caused by the protruding braces.
With the guitar sides in the mold, position the back of the guitar onto the sides. Using a shaped pencil with plenty of ‘lead’ exposed, mark the position of the bracing that protrudes from the guitar and mark the Kerfing which will need to be cut out to accept the braces for added strength. Remove the back and view the marks on the bracing and allow an extra 2-3 mm depth before cutting off the protruding pieces of the braces. View the Kerfing and add a small insert to the Kerfing where the cuts will weaken the remaining Kerfing when the back is in place. Once this has been glued with quick drying superglue, make the cuts at an angle so as not to cut the rosewood sides of the guitar, then remove the material between the cuts with a chisel to depth using a piece of the brace which you have removed earlier for a tight supporting fit. A similar process will be done when attaching the soundboard.
Once complete with all the cutting and chiseling, check to make sure that the back and sides are level, make adjustments if necessary. Use a torch light and shine the light from the inside of the guitar body to assist with the process. If light is visible from the outside, you have gaps.
When no gaps are discernable, you can proceed to gluing the back to the sides.
Use Titebond and allow to dry for 90 mins to to hours until glue is clear. Guitar body should still be in the mold at this point and should be clamped down using the adjusted clamps made specifically for this purpose as shown here.
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Gavmeister
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