Friday, January 29, 2010
Friday, January 22, 2010
Saturday, January 16, 2010
The archtop is really coming along now. This week I finished up binding the body with ivoroid binding. The ivoroid is in some ways easier, but also proved to have some trickier parts as well.
Here is just another picture of one more of my guitars with binding slots cut. There is one slot that has yet to be cut in this picture... An extra binding piece goes along the edge of the end of the cutaway. The ivoroid binding process involves melting the interior of the binding in sections with acetone before applying glue. I believe this creates a better mechanical bond and also sort of allows the binding to form to any imperfections in the wood. Butt-joints also get a dab of melted ivoroid material to help, ..seal the deal.
Here is the body before binding. It was actually the easiest guitar to box up just because there were no braces to tuck in it underneath the kerfing. So, that knocked out a few steps and made for a very clean joint inside and out. We were actually shown how to bring in the excess overhanging plate material with the pneumatic random orbital sander which saves time for sure and does a great job.
On the inside of this guitar, there is a much less complicated brace pattern, I won't try too hard to describe it as you there is a lovely picture of it posted here. Just one X-brace and then a couple of cross braces. The only tricky thing is that the braces must conform accurately to the unique inner dishing of the plate. This is accomplished by tracing the approximate shape onto the brace edge, shaving the bulk of the material back and then bringing in the rest by pulling sandpaper between the two pieces until a tight fit is achieved. There are no braces on the back of this guitar.
Here are a couple pictures of the kerfed lining in this guitar. It's really no different from the other guitars aside from the addition of the cutaway side. So all we do here is shape the kerfing end to fit neatly between the headblock and the side. This guitar by the way, has no radius shaped into the sides since all of the top and back radius is carved into the plates, producing a flat perimeter.
Friday, January 8, 2010
So after the plate is cut to shape, we use a spindle sander to sand the profile right up to the final line and then use a router to cut the edge to its final thickness, which is 3/16". This plate here with the plane sitting on it is the aforementioned spruce top. We have to smooth the contour of the plate's inner portion into the final thickness edge we just cut. We use that little plane there for this job
The surface of the edge is colored with pencil to help you see if you are hitting it with the plane. Since it is already at final thickness, we do our best to not hit it.
After the contour is blended into the edges with the plane, we have to scrape and sand the contour completely smooth so that there are no high or low spots. The scrapers will do a better job of blending than just sanding will, so we do our best with the scraper, and then finish up with sand paper. The sandpaper alone could make it appear to be smooth, but when held to the light may show shallow spots that will only be more obvious once the glossy finish is on it. The outside must be completely shaped and sanded before we start carving the inside of the plate in order to keep our desired thicknesses in check.
When we are ready to carve the inside, we set up the drill press with a depth stop, registering off of a pin rather than the table. This allows us to drill holes all over the plate to precisely the final thickness. We then use that trusty finger plane to bring the material thickness down to the bottom of the holes. It's really pretty fool proof. But, this is where it's obvious why arch tops should cost a lot. I have the hands of an old-timer today.
So long story short, my plates are now done. We used another router jig to cut out the F holes on the top. The jig fits over the whole top from the back side, and locates off of the holes in the excess wood at each end of the plate. I also made a lot of progress on the bridge and saddle for this guitar. I got the sides bent and glued up the the head and tail block, and even cut out the pearl inlay for the headstock. Sorry I don't have pics of that stuff now, but more soon!