Day 4

Monday, Monday, Monday!  Monday was a productive day.  As I mentioned in my last post, I didn't have enough battery left on my phone to take a picture of the completed back, and would include one on my next post.  Here're two!

As you can see, there is still some final cutting to do, which will be done once the back and soundboard are ready to be joined.  But for now, the back is completed.  Before the body is assembled, the soundboard must have its braces glued on, shaped, and scalloped, the rosette must be applied, the soundhole must be cut out, and the sides must be dressed and planed/scraped-to-thickness.  A few of these steps were started, today!

The first thing I did in the shop today was some scraping.  I pulled out the good ol' wood scrapers, and started dressing my soundboard.  The exterior surface was already finished, but the interior needed lots of work.  I scraped away at that for a good hour or so, until the thickness was suitable.  The core of the soundboard is slightly thicker than the edges, due to the speaker effect that I mentioned before.  The sides are thinner, to allow optimal sound delivery, just as a loudspeaker has its electromagnetic core, and fibrous cone, surrounding it.  The objective thickness was about 2.5mm for the core, and about 2.0-2.2mm for the exterior edges.  The top of the soundboard is allowed to be a bit thicker, as it is mostly there for structure, while the lower and wider portion of the guitar is the primary sound-producer.  I scraped some spots a bit more than was necessary, and thought that it was too thin, at one point- but upon assessing the situation, Ned and I determined that everything was fine, as some of the thin spots were on the very edge, which will be trimmed off, later on down the road.  All's well that ends well!

Pictured above, is the incising compass (made by Ned)
used to score the circular outlines of the rosette channel.

Once the soundboard was properly dressed/scraped-to-thickness, I put the soundboard template on top of it.  The template has a series of holes in it, marking the ends of each brace location, and the soundhole's center.  I used a pencil to mark each of these locations.  I proceeded to drill a hole, where the center of the soundhole was marked- this hole was sized to fit around a peg, seated in a board we used for the rosette application process.  The next step was the marking of the rosette channel- this is done by scoring two concentric circles on the soundboard's surface:  One is the outline of the soundhole, and the other is the exterior edge of the rosette channel.  I did a couple test runs on a piece of wood Ned had kicking around, which went well (Ned complimented my circle cutting ability, and said that it was a very nice circle.  It was, indeed!).  For this process, I used a little rig that Ned had made, which was comprised of a small wooden dowel, two small blocks of wood, a couple wooden pegs, and a small blade.  He's a handy guy!  This device is essentially a specialized compass, used specifically for this task.  One of the wooden blocks has a divot on the bottom- the peg that the drilled hole fits around also goes into this divot, as a centre point for the incising compass.  I carefully cut the outline of the soundhole, handed the rig to Ned, for calibrating, then cut the second/outer circle.  It was done! 

A rosette

The next step was to chisel out the space between the two concentric circles- this was to be the channel that the rosette would fill in.  I've used the term "rosette" a few times now- to anyone reading who doesn't quite know what a rosette is, I'll tell you, now:  the rosette is a decorative ring that is found around the soundhole of a guitar.  It is a circular mosaic, made with many tiny pieces of coloured wood, each being approximately the size of a grain of sand.  In today's industry, many mass-produced acoustic guitars have rosettes that are mere decals, but in most quality guitars, the rosette will be an actual mosaic.  One can only appreciate the work that goes into this decorative ring by looking very closely at it, to see how detailed it truly is.

The chiseling of the rosette channel

Ok, back to the process!  Next, I began chiseling between the two circles I had cut.  This is a tedious process, as you have to be very careful not to touch the soundboard, beyond the score marks.  Most people might stress over this, and get anxious, but with my personality-type, I found it to be relaxing, and meditative, even.  I enjoy "obsessing," for lack of better terms, over tiny details like this.  The channel was only to be about a millimeter deep, as the rosette is not very thick, and the soundboard is just over two millimeters, as it is.  I continued to cautiously chisel away at the wood.  Ned had started the process for me, to illustrate a good technique to prevent the chisel from shooting forward, whilst applying pressure in the process.  Once I had it down pat, I spent a good half hour or so making everything as it should have been.  The very top of the circle didn't need to be chiseled out, as it would be underneath of the fingerboard, and furthermore, it would probably maintain more structural integrity by being left as it was.  I let Ned check my work a couple times, and after tweaking it a bit, I was done with the chisel.  At this point, we placed the rosette in the channel, to make sure it fit properly- and it did. 

Now, in all of reality, it is hard to have a product like a tiny wood mosaic rosette that is completely and perfectly circular.  The lines I cut for its channel, were, however, perfect circles- this meant that once we glued it in, we'd have to manipulate it a bit for it to properly conform to the perfectly circular channel in which it would be seated.  While the margin of error was only a millimeter or so away from it being a perfect circle, it was still a fragile process.  One must be gentle when handling the rosette, as to not damage it in any way.  Ned also informed me that once the rosette came into contact with the glue, we'd only have roughly 7 seconds to fit it in properly, before it would start to swell a bit, and become harder to manage... the pressure was on.

The clamping setup of the rosette application

I prepared for this process by putting aside 4 clamps, and a sheet of wax paper, while Ned found a square piece of wood which we'd use to clamp onto.  We used two types of glue- well, they were the same type of glue, but one of the bottles had been diluted, making it thinner.  The less viscous of the two was applied first, with a generous strip around each edge of the channel, followed by a single circle of the thicker glue, in the middle of the channel.  We then blended the glue, to ensure that every last bit of the channel was saturated with a generous amount of it.  Now it was time to set the rosette.  The bottom went in first, and we then shimmied each side of it into place.  It started to resist a bit, so I let Ned take over, for this, as he has much more experience than I.  I assisted where I could, and finally, in a matter of seconds, it had been wrestled into place.  I quickly grabbed the sheet of wax paper to put over it, and the piece of wood, to seal its fate.  Applying pressure the whole time, we grabbed the clamps, and put them tightly into place.  Phew!  All of this took less than a minute, but it was pretty intense.
The whole clamping setup was put aside to dry, and I began a new task.  Since my back was completed, and my soundboard was currently untouchable, Ned directed me to start working on the braces that were to be used for my soundboard.  I laid them all out, and Ned directed me as to what was to be done.  I measured each of the brace planks to fit a corresponding brace marking on the soundboard template, marked it, then cut it with a Japanese-style paddle saw, which cuts on the pull stroke.  After cutting each brace to length, I sanded one side of it until it was smooth and flat, then tested it against a square, to ensure that the sides would be perpendicular to surface of the soundboard.  There were fourteen braces to do.  Twelve of them were the same height and width, while two of them were a bit bulkier- these two were to be the harmonic bars.  I numbered each brace to correspond with numbers on the template, so I knew which length fit where.  This process was my last one of the day.

The soundboard's braces, numbered 1-12, and the harmonic bars, labeled "A" and "B."

I proceeded to cleanup my workspace, and then checked the clock.  It was fifteen minutes until quitting time.  I considered starting on the planing/scraping of the guitar's sides, which were still untouched, but decided against it, as I only had fifteen minutes left, and had already cleaned up- planing and scraping would just make another big mess.  At the end of the day, I had finished dressing my soundboard, chiseled the channel for, and applied the rosette, and prepared all of my soundboard's braces.  Before leaving, Ned asked me if I could come in the following day, after work, to do some work on the rosette- his reasoning was that it would be much easier to scrape away the excess glue before it had completely hardened.  I had scraped away the glue from my back's braces the same day we had glued it, and it made it much easier.  So tomorrow evening, I'll be going in to do some finishing work on my rosette- look forward to a supplementary entry, tomorrow evening!  Thanks for reading!