Back in the Shop

In my last post I got caught up on the blog posts and my working status on the guitar. I mentioned that the Fall semester was over and that I was hoping to use the time over Christmas break to get back to work on the guitar. Well I did just that! Most of my previous work had been done at Matt's shop but I brought most of the project home at the end of summer to work on it in my garage shop at home and to get it out of Matt's way in his shop. I thought I would be able to work in the evenings at home and continue to make some progress. Well, that didn't seem to happen but now with a few free days I was able to start working again.

At the end of the summer Matt and I built a little jig to help laminate plastic binding strips together. It was a simple little contraption based on a Stewart-MacDonald design that I had seen in their catalog.

Binding Laminator

The idea was to apply acetone to the plastic strips and run the two strips through the spring loaded jig to glue the strips together. The jig worked well but I quickly realized that, like most things, this would be much easier with two people. On my first attempt the strips weren't aligned properly but I was later able to sand down the mis-aligned strips and make them a uniform width. The next strips were a little better but it was difficult to get the acetone on and run the strips through the jig quickly before the acetone dried. I found that I could only do a few inches at a time.

Laminator

Laminator in vise

Running black and white binding through spring loaded jig.

Pulling binding sandwich through.

applying acetone as glue.

All the materials.

My goal was a black and white binding on both the top and back with a black and white purfling to match the outer and inner rings on the rosette. After laminating the binding strips and the purfling I sanded the edges to clean them up and get them ready to adhere to the guitar body.

The next step was to rout the channels on the body edge to accept the binding strips. I purchased an attachment for my Dremel Precision Router Base from Stewart-MacDonald called an edge guide to help me cut these channels. This tool allows for very accurate and delicate depth settings to match the width and thickness of the binding material.

The edge guide attached to the Dremel tool.

The purfling channel was cut first to the depth of the purfling and the width of both the purling and the binding. After that channel was cut on the back the body was turned over and the same channel was cut in the top. The edge guide and bit depth were then adjusted to fit the binding. This channel was then cut in both the back and the top.

The Dremel tool routing the purfling channel on the back.

The Dremel routing the binding channel on the back.

Binding and purfling channels on the back.

Detail of both channels.

Detail of both channels on the back.

Channels being routed on top.

Top with channels cut.

After the channels were routed in both the top and back they needed to be cleaned up with an assortment of small jewelers files, fingernail files and emery boards. The channels needed to be burr free and a consistent depth to fit the bindings. At this point I realized I had some problems with consistency in my channel width. After close examination I saw that I had a couple of places on the top of the back that the channels were not as wide as they should be. I think the reason for this inconsistency was due to some imperfections in the sides caused in the bending process. I now think that if I had spent some time sanding out the sides this might not have been as big a problem. The edge guide uses the sides as a bumper/guide to control the cut. If there is a bump or valley it will be transferred to the channel cut. Also, if the sides are not perfectly square (which I am sure mine were not) the channels will not be consistent. I spent a lot of time trying to work out the inconsistency in the channels and still had some problems when I glued the bindings in place.

An emery board makes a great tool because it is flexible.

Tools used to clean up channels.

Attaching and gluing the bindings in place presented another challenge. All of the research I had done indicated that you could glue both the purfling and binding in place at the same time. This proved to be to difficult for me to accomplish. The glue that was recommended was a solvent based glue similar to the old fashion model airplane glue that I used as a kid. This glue is very fast drying glue and is very messy. There was no way I could apply the glue to all parts and get it in position without having a drying problem, not to mention having glue all over me and more importantly the guitar. I quickly decided to attach the purfling first then go back and attach the binding. This took a lot longer because I had to allow the glue to dry at least an hour before applying the binding. Again, like the lamination process, I found that I could only work in short (4-6 inch) segments. I would apply the glue then go back and fit the binding in place then quickly secure it with a piece of painters' tape and move down about an inch and repeat the process. The painters' tape was used so the low tack adhesive would not pull up the wood fibers on the soft spruce top.

Applying the tape to hold the glued binding in position

Purfling glued in position.

Detail of purfling.

Detail of purfling.

Detail of purfling showing the end seam.

Binding on back fully taped.

Purfling on top fully taped.

Binding and purfling installed.

Detail of binding and purfling at waist of top.

Binding and purfling on back.

Completed binding.

The materials.

Trimming the Top

After the glue has dried I get my first look at the assembled top and sides. It's really starting to take shape. I have to admit I am getting pretty pumped about my progress. The next step is to trim and finish the overhang on the edges. For this I get to use a trim router and a laminate bit. I have cut and trimmed a lot of laminate with this setup but never any wood or wood veneer. I am a little concerned about chip out, so like most of this project I am prepared to take it slow.

First look at the glued top and sides. Notice the overhang of the top.

Inside view showing bracing.

Detail of bracing fit against kerfing.

Attached top showing overhang.

The assembled top and sides must go back in the Salera to hold it securely for the trimming process.

Top and sides in the Salera.

The L brackets holding the guitar body in place.

The Salera and body clamped to the work bench.

The direction of the router cut is very important to reduce the chance of chip out. I took it very slow, maybe a little to slow as you can see from the burn marks, and managed to get by with only one very small chip out that will be hidden by the binding (edge treatment) that will be applied later.

Trim router removing the overhang.

Detail of router.

Trim bit showing the bushing guide.

After the top overhang was removed a little hand sanding was all that was necessary to smooth out the edges. The next step is to prepared the back edges of the sides in preparation to attach the back. Remember the back sides are not flush with the end blocks, so quite a bit of material needs to be removed, especially on the top or neck of the guitar. The bottom of the sides were somewhere between an 1/8" and 1/4" high, while the top was over 1/2" high. This material needs to be removed so the end blocks are flush with the sides and there has to be a smooth arcing transition from top to bottom. After thorough research in all of my books I realized there were a variety of ways to go about removing this material. Some of the books suggested removing the bulk with a band saw others recommended using chisels and then finishing with the sanding board using a rocking motion to get the final finished arc. The amount I needed to remove was considerably less than all of the books, so I decided to try it with the sanding board only. It seemed to me I would have more control although it would take longer. I was in no hurry so. . . The first thing was to draw a guide line to follow while I was removing the material. I measured down on the outside the appropriate distance on both ends. Then calculated a couple of mid points and drew tick marks. I used a flexible rule to connect all the marks and drew a line.

Pencil guide lines.

Guide lines at the waist.

Guide lines at the neck.

Then I started sanding and sanding and sanding and sanding. . . It too k a while but I was able to control the transition and ultimately I was able to get a great fit.

Using the sanding board in a rocking motion.

Detail showing under side.

Using the board to check for flatness.

An added advantage to using the board was being able to check flatness at the ends. While the board was at an angle if I could see daylight I knew I needed to take more material off at that angle. Once I was satisfied with the arc and was sure the sides were at the right height, I was ready to trim the braces on the back and apply the kerf lining to the sides in the same manner I used on the top.

Trimming braces to length with a dovetail saw.

Using a chisel to remove cut ends.

Refining the brace shape with a chisel.

The body was placed back in the Salera in preparation to glue the back in place. Once the back is glued on I would no longer have access to the inside of the guitar, so at this point I signed and wrote a simple message. Similar to signing a painting or dedicating a ship on its' launching. This was a little silly but it felt very important. I think in lieu of champagne, Matt and I went and had a beer.

Glue was applied and like the top the spool clamps were used to hold the back in position while the glue dried.

 

After the glue dried, I took the "Closed Box" out of the Salera and marveled at its' beauty. Like before I trimmed the overhang off the back with the trim router and finished with some hand sanding. WOW, it really is a guitar! Even though I had been working on this for several months, and I always had faith that I could do it – its' really a guitar! I'm amazed – its' really a guitar!

AND NOW SOME SERIOUS AIR GUITAR!!!