Bending the Sides of the Guitar
This is the wood that I used for the back and the sides - it’s German Pearwood. I picked it up at Gilmer Wood Company in Portland. It’s a fairly hard wood and has beautiful oranges and red hues in it. Interestingly enough, it doesn’t really have much of a smell to it, even when it’s sanded.
The first thing we did, to prep for bending the sides was to sand the pieces to the appropriate thickness using a drum sander.
This is Jay’s hand-built jig for bending sides, modeled after the Charles Fox side bender.
First we put the side between two aluminum sheets (this type of heating blanket can be purchased at a luthier supply store), turned on the heat to low and applied water. As you can see, there are holes in the aluminum sheets to allow for water to get through to the wood and steam to escape.
Once the wood was warm enough to flex, we slowly turned the crank on the top, allowing the wood to gently slump into the mold.
As you can see from the above picture, once the wood was hot and wet, it gradually and naturally started to lay down over the other areas of the form. We then attach two of Jay’s rollers to the jig and slowly rolled the top and bottom of the shape into place until they were firmly held against the jig. At this point, we turned down the heat on the blankets and allowed the side to bake and then cool slowly.
Once the side was cooled we removed the top aluminum sheet and, in order to allow it to continue to slowly adjust to room temperature and cool slowly, we left the bottom sheet on warm.
This is the finished side after it was removed from the side-bending jig.
The next workday, we did the same process with the 2nd side.
Bending the Kerfing
Kerfing is used to provide support to the inside of the sides of the guitar. Jay cuts his kerfing from the same hard mahogany that he used for the guitar neck. He has a back room full of large mahogany boards that he cuts down to size and then (as you can see in the picture below) runs through his jigsaw to create grooves in the strips - this allows the kerfing to flex when it’s attached to the curved side form.
Prior to attaching the kerfing to the guitar sides, we used the bender to give it the same shape as the sides. Even though the kerfing is fairly flexible, shaping it prior to attaching it to the sides alleviates some of the strain on the mahogany and minimizes the risk of cracking or fracturing to the wood.
and the finished bent kerfing, ready to attach to the sides…