Falcate Classical Guitar Build Blog:
Fabuary 10th 2015
I managed to finish the the rims today. From my last post I finished up the solid linings for the top and I used reverse kerfed linings for the back.
I still just used a bunch of clamps to both laminate the linings and glue them on to the rims at the same time. The non-cutaway linings were a bit easier to glue down.
I sprayed the reverse kerfed linings with water and used the out side of the rims as a form to attempt to pre bend them.
With the top linings in I profiled the back rims to get ready to accept the back linings using a 10' radius dish. I really had to take care here as I not only wanted to get the back radius but I also need to slope the back neck to tail during this stage. I had lots of sanding. I need to get my profile a bit closer.
I did not need real strong clamps to glue the kerfed linings down.
With all of the linings in I cleaned up both the top and the back. I sanded the top linings with a flat board and the back again with the 10' radius dish. I pulled the rims out of the mold to check that the top face was still square to top rim.
My rims have a mounts that I can add side weight to. The side weight would allow me to lower the resonance of the top if required without changing the other resonances in the guitar very much. I will not get into why it has the effect as it is explained well in the book.
I notched the linings using a scalpel, razor saw and a chisel to accept both the side weight mounts and the side splints.
I also used a scalpel, razor saw and a chisel to clean a channel for the end graph. I tried to leave this until after routing the bindings on my last couple of guitars but I decided for me it is easier to install this now, and deal with a bit of hand routing to get the purflings mitered later than to cut the channel with the top and back already on.
Tomorrow I will start on the falcate braced top.
Fabuary 12th 2015
While waiting for my sound hole patch glue up to cure I thought I would post how I make falcate braces. I have a bunch or pictures so I will post comments in line with the photos.
I had a plank of German spruce that was just a tad over the thickness I needed (22 mm) to make two braces each for the two pair of falcate braces on the board.
I ripped the brace stock to about 2.2 mm and used my thickness sander to take it to 1.7 mm. Three plys of the strips makes a falcate brace just over 5mm thick.
I used some tape on my molds to mark out the length of the brace and the center of the bend and transferred those measurements to the strips
Not shown, I used my bending iron to shape all the braces very close to there final shape. Care must be taken as spruce is not the easiest wood to bend. I found it weird that even though all of the wood can from the same stock and they were all the same thickness, some bend easier than others
Too lay up the braces I used structural epoxy and strap clamps on my falcate brace molds. I coated the top of each of the braces with polishing wax so that the braces would release from the mold. In the past I also used wax paper, but found it was hard to avoid a big mess. I decided to trust the wax on the mold.
My shape must be a little off as I need the rubber band to pull the long side of the brace tight.
Luckily both braces released from the mold. Later I will split each brace to form the two pairs of falcate braces.
I started to prep the top, sanded it to thickness, transferred the brace pattern onto it and fabricated and glued on a sound hole reinforcement patch. I would have been happier if the sound hole cut off did not drop out while sanding the top, but I went a bit deep when I routed the hole from the top side. Not a real big deal, I just need to find the center of the sound hole against the patch so that I can route the patch.
Fabuary 1th 2015
So now I am very close to finishing the top, back and rims for this guitar. My current plan is to press non radiused falcate braces in either a 8m or 10m dish, Glue the transverse brace down flat. Also the top rims are profiled dead flat. My past three classical guitars have been built Spanish style with a flat solera with a dished lower bout. So I have always profiled the top rims flat. I am going to have a bolt on bolt off neck and use a wedge under the fret board to set the angle. At this point I intend to leave the top rims without a radius, but I still am at a point where I can still profile them and am open to suggestions.
Here is what I have so far.
Fabuary 1th 2015
I had a couple of days of messy epoxy work gluing down the braces in a 32' radius dish. I am getting a little better handling both the epoxy and the carbon fiber. From my last build I took care to not have too much epoxy. In that case the CF would float out from under the braces when I clamped them. I also need to make sure I have enough though. I put a thin film on the top following the marked brace lines. I wet but also squeeze off the CF and I also put on a thin film of epoxy to the brace as well. Another big improvement to my process is I bought a set of metered pumps for the epoxy, eliminating the need to weigh the reason and hardener to assure the correct mix. In my case one pump of each is perfect. The set included a pump for the clean finishing hardener as well West System 207, so I my try to pore fill with it. From what I heard is less amber, more water clear than zpoxy. I do not have enough go bar rods to do all the braces at once so I did two separate sessions. Sorry I do not have pictures doing the glue up, My hands ually have too much epoxy on them to hold my phone.
I carved and shaped all of the braces to their final heights. No tap tuning as there is no way to correlate what happens after the top CF is applied. So I just shape to the heights I came up with to get the desired stiffness. I am about one mm lower than the two falcate SS I did.
Just making sure the braces are terminating where I want them to as the next step is to top with CF, which finishes the brace.
With the CF epoxy to the top of all of the braces. The fan OF CF in a small pool of epoxy at the end on the braces is to hold down the CF to keep it from lifting off the top.
Once this layup cures I will epoxy the transfer brace down using a completely flat gluing caul (no radius)