Bindings and Purflings


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I had developed a binding/purfling scheme with Dan Biasca--placing differing colors next to each other. Further, I designed a purfling scheme for the end flash (more below).
To start, I placed the curly maple bindings on the bench, all four together with one side up and using a scraper, smoothed the sides for gluing the purflings. I then, one binding at a time, applied glue, then...
Carefully placed the purfling on the gluey binding. I made sure that the purfling was flush with at least one edge. Once the black purfling was in place, I applied more glue and placed the white purfling. These are the purflings that will be exposed on the sides of the guitar. I then wiped excess glue off of the bindings.
When I had glued the purflings on the bindings, I taped the bindings together in pairs as shown. This does two things--first, it helps the combination keep from bending due to the glue moisture, and second, it puts the pairs in the right configuration to bend a left-right pair.
I considered the methods for bending the bindings. I could have used a pipe/propane torch combination, an electric iron, or a bending machine. After some questionable experience with the pipe/propane torch (my sides scorched badly), I decided to build a bending machine, which you see here. I used the photo of a similar machime on the LMI website as the model. All together, and using new hardware, I spent about $80 and 8 hours of time to build this. A new machine would have cost around $500. I used a timer and dimmer to control heat--provided by a 300W and 200W bulb combination.
Before I placed the bindings in the bending machine, I throughly wet them. This proved to be a mistake, as you'll see below. However, the bending machine worked well and I had two sets of bindings in roughly the correct shape for the guitar.
After pulling the bindings from the machine (I heated them for 1/2 hour and left to cool overnight), I removed the tape from the bindings. It wasn't difficult to remove the tape, even though it had "cooked" in the machine.
When I looked closely at the bent bidings, I discovered that the purflings had delaminated in several places. I searched the web and found out that the likely cause was my wetting of the bindings before bending.
I cleaned out most of the dried glue from the gap between the delaminated purfling and bindings, and then re-applied glue and clamped. I needed to do this in about 10 places. Next time, I won't wet the bindings. They repair worked well.
Now for the scary part--I need to cut the channel for the binding and top/bottom purflings. To do so, I had purchased a router bit set from LMI, which is specifically designed to cut a 0.80 " rabett for the binding and 0.140 for the purflings. I carefully set the bit depth...
...And then I set the roller so that I could have the router ride against the side of the body.
I made a test cut on a scrap of wood and checked it with a small piece of the binding. Looks OK so far.
Since the ourter will register against the side of the guitar, I carefully scraped the sides to their close-to-final condition.
Then, I made my cut, ensuring that I cut "with" the grain, requiring four separate passes on the top and four on the bottom. I had to carefully ensure that the router did not tip toward the center of the guitar. The result is the channel that you see here. I cut the binding channel first and the purfling rabbett second. Next time, I think that I'll cut the purfling channel first. I think that will give me a better result.
Once the bing channels were cut, I could install the end flash. I designed the end flash shown, and cut a formica template in this shape.
I used the template to cut the flash shape from some scrap curly maple that I had. I thicknessed it down to about 0.90.
Then, I laid out the flash on the end of the guitar with a knife and cut it out with a chisel, down to the end block. I carefully ensured that this area was flat, so that the flash would glue properly.
Referring to my plan, I placed black/white bindings on the sides of the flash, and then put in place. When in place, I could mark where it need to be trimmed for the top and bottom bindings, and I cut just short of this mark so that I could place single black bindings on the ends. This should create a great pattern.
Then I glued the end flash in place. This is the last step before installing the bindings.
Elapsed time for these steps: 8 hours... See the main page for the cumulative time.  
The day after I installed the end flash, I decided it was time to put the top bindings in place. I wish I'd started with the back, but I didn't have the right purflings. Why did I wish I'd started at the back? You'll see. Here, I've temporarily taped the bindings to trim the first binding at the ends.
I began by putting glue all along the binding/purfling channel (a mistake) and then, starting at the waist, I used tape to pull the purfings/binding in place. Here you can see one side taped up. My visitors were glad to come and visit. They haven't seen me for awhile. Note that I had taped the bindings all along. This prevented me from seeing a problem that showed up later...
Here's a little more detail at the small bout. Note that I have used a system to immobilize the body while I applied the tape. This turned out to be a great idea, since I need to put on a fair amount of force to pull the tape taut.
Before I set the second side of the binding, I temporarily taped it to trim the bindings and purflings. I found that the purflings were best trimmed as the bing was installed. It was pretty difficult to juggle purflings and bindings and tape and glue all at once. I used a much better method on the back.
Finally, everything is glued in place, and I'll leave it overnight to dry.
When I remove the tape, I discovered that the bindings had pulled away from the waist. I needed to correct this condition by cleaning out the gaps and putting in epoxy that I mixed with ebony dust. I attribute this situation to not enough pressure on the tape. I didn't detect the problem because I had taped the entire area.
Elapsed time for these steps: 10 hours (not including building the bending jig)... See the main page for the cumulative time.  
I had to order some additional purflings for the back, so I had a week to consider the problems I had with the top bindings. I decided to use a different technique, which you'll see below. It was much more successful. Here, you can see that I'll install a b/w/w combination of purflings that will be visible from the back.
I decided to sequence the binding/purfling installation as follows: First, I'll install the bindings and tape them as needed to hold them in place. Then, I'll install the binding. I also decided that I should apply glue to the entire channel at once; rather. I applied glue in about 6" strips. Here, you see where I am testing the purfling installation at t he end to make sure the purfling channel is properly cut.
Starting at the waist, I glued on the purflings strips, applying tape as necessary. Here, one side of purflings are glued in place and I'm ready to immediately start installation of the binding.
I prepared sets of doubled-up tape for pulling the bindg in place. This allowed me to apply much more force in pulling the binding in place. I started at the waist and put only as much glue in place as I could cover with about five pieces of tape. Additionally, I left space between the pieces of tape so that I could detect whether and binding areas were pulling away from the body. Here, you see me applying tape to the binding by starting t he tape at an angle and applying force both across and down. This process worked very well and was much less stressful than the procedure I had used on the top.
The completed binding glue-up on the bottom. It went faster and worked much better than on the top.
Finally, to unsure that the critical waist area remained tight, I placed the glue-up in the mold and used small shims to apply additional pressure at the waist. The result was a very nice glue-up. This is the method I'll use next time.
I removed the tape the next day, and planed off the excess binding/purflings.
Finally, I scraped the sides down to almost final finish.
The bound guitar looks great. Here's the front...
...and here's the back. The body's now all done. Next step--assemble the neck to the body.
Elapsed time for these steps: 12 hours... See the main page for the cumulative time.  

The next step-->>Assembling the Neck to theBody and Adjusting the Frets

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