Four Part Harmony

Howdy folks. Time for a quick update on the guitar project progress.

It’s been several weeks, but at some point recently I got up the nerve to try to do the side bending. You’ll recall I built this contraption, which was supposed to make the process fairly foolproof. This picture shows the bender with the lights on, heating up.

I took one side, sprayed it lightly with water, wrapped it in some paper, and sandwiched that between the two aluminum slats you can see in the picture. Then I slowly brought the center clamp down tight, followed by the lower bout clamp, and finally the upper bout clamp. It was a little nerve wracking, but everything worked perfectly. No cracking or splitting or explosions or fires.

Here’s a closeup, in which you can kind of see the side clamped between the aluminum slats. This is at full clamping pressure. The fit was pretty good. I left each side in the bender at full heat for about 15 minutes, then shut it down and let it cool overnight.

Then I took the side out and clamped it into the mold to help it keep its shape. I ended up using a lot more clamps than this, as it was important to keep the sides square all around, and very tight to the mold.

The drawback of the bender is that I think I needed to exaggerate the curves to compensate for the woods tendency to want to spring back. I’ve subsequently had the sides back in the bender three times (I re-bent them again last night). They hold their shape pretty well, but still want to splay out at the ends. At this point, I wish I had gone the old-school route, gotten a blowtorch and a length of pipe, and bent the sides that way. More room for error, but much more control.

Here’s both sides bent, cut to length and fit within the mold. In terms of the fit, everything seems just fine. At this point, if they would just hold their shape, I could glue up the end blocks and start working towards joining the back to the sides. I still have plenty of other work to be done though, so I have to keep reminding myself that there is no hurry.

One of the other things I have managed to get done is to glue up the soundhole rosette, which needs to be done prior to bracing the top. I decided to use a herringbone purfling and rosette, which is similar to (but not exactly like) what they used to use on classic old Martin dreadnoughts. Here it is being clamped up and glued into the top.

Another photo of the clamping. When this was all dry, I used a scraper and a big sanding block to get rid of any dried glue and get the rosette down flush with the rest of the top.

And here’s the finished product. That gap at the top is supposed to be like that. It’ll be covered by the fingerboard eventually. This picture also really shows the figure in the top as well.

Next up: gluing up the sides (eventually) and bracing/voicing the top.