OM Acoustic Build (Mark Bailey Course)

ArchtopDave

The wrapped wood then goes into the Bending Machine with it and the heater sandwiched between two metal plates.

https://lh3.googleusercontent.com/-x2PxJMy53gU/VtcyyFxgAwI/AAAAAAAABnY/r6_eO2dNOUM/s800-Ic42/DSC_0275.jpg

Then the central clamp is steadily tightened, as in this photo.

ArchtopDave

The Spring loaded clamps are the pulled round.

https://lh3.googleusercontent.com/-XRnlCeWVPSY/Vtcy0cpHSRI/AAAAAAAABng/fUdJR2nHDq0/s800-Ic42/DSC_0269.jpg

You can see the temperature control under the Machine (250 degrees). The fine white wire going up the Upper Bout side of the Machine is a Thermostat probe (the end is in under the heater). If my memory serves me right, the heater is left at the maximum set temperature for 10 minutes. Then it's switched off, and the wood left in the Bender overnight.

ArchtopDave

As I mentioned above, I bent the Cutaway Side by hand.

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Here's the Bender, which is shaped just like a little, rather hot, airplane wing.

Behind it, on the bench is my Cutaway Side, and  partly visible on the right is my non Cutaway Side being held in shape in a template support.

ArchtopDave

https://lh3.googleusercontent.com/-KX8SYp3lDYM/U77hrW0kYKI/AAAAAAAABkU/DKbMDWONU18/s800-Ic42/DSC_0044.JPG

Cocobolo is quite an oily wood. In this photo, the wood around the Cutaway looks very dark, almost black. This is because the oils in the wood have come to the surface, when the wood has been heated, during bending.

ArchtopDave

ArchtopDave

Kerfings then need to be bent for both edges of both of the Sides. This is all done by hand.

https://lh3.googleusercontent.com/-Q7w8qHvB3pg/U77gsK_M6dI/AAAAAAAABkU/Ca_Ebbz5mwg/s800-Ic42/DSC_0055.JPG

ArchtopDave

https://lh3.googleusercontent.com/-yJuLo7-cF8c/U77iVreJCqI/AAAAAAAABkU/QeMYFdh4lcw/s800-Ic42/DSC_0057.JPG

https://lh3.googleusercontent.com/-pNwQARkeDN8/U77hkAP-ndI/AAAAAAAABkU/CU_cMqCQdQ4/s800-Ic42/DSC_0059.JPG

ArchtopDave

The Kerfings for Top Edge are glued on, and the sanded. Again, as with the Braces, the inner edge of the Kerfing is deliberately round by sanding.

https://lh3.googleusercontent.com/-52YbPl6U7xI/VrfV_teC_NI/AAAAAAAABkU/RWwFN6OG2II/s800-Ic42/DSC_0085.jpg

Andyjr1515

Nice job. Reverse kerfings and rounded too! That's a touch of class

ArchtopDave

Next job is quite a big one - adding the Braces to the Top and Tap Tuning them.

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A bit of drawing on the underside of the Top. You can just see the bottom edge of the Sound Hole at the top of the photo. 

There's a straight line horizontally across near the top of the Bridge - this, besides the centre line, is the most important marking, as it shows where the Saddle will be. The Bridge is then drawn in relation to this line. This then allows you to position the main X-Brace as shown. Obviously the two arms of the X-Brace have to meet at the centre line. Additionally they have to run beneath the Bridge, as shown, to support it, and have to pass either side of the Sound hole (just visible at the top of this photo).

ArchtopDave

As I mentioned awhile back, I made all the Braces for the Top Bracing out of Adirondack Spruce. The X-braces were simply clamped carefully in position to allow the Bridge Plate (Rosewood) to be made accurately. When the X-Braces are eventually get glued on, they need to be in contact with the sides of the Bridge Plate. As with all the other internal woodwork, the exposed edges of the Bridge Plate are sanded to round the edges off.

https://lh3.googleusercontent.com/-BvQOEUH6J64/VrfXk0edSzI/AAAAAAAABkU/8RZ9X2mQeaU/s800-Ic42/DSC_0069.jpg

Then glued.

https://lh3.googleusercontent.com/-j7nRje9DOE8/VrfUgcUhMRI/AAAAAAAABkU/Tg7AuAsX2jo/s800-Ic42/DSC_0071.jpg

ArchtopDave

The positions of the other Braces are marked out, and a start made on glueing some of them in position,and then shaping them.

 https://lh3.googleusercontent.com/-vupBa_ReKXM/VrfUlkk_m1I/AAAAAAAABkU/UWGK8MxgBrM/s800-Ic42/DSC_0073.jpg

https://lh3.googleusercontent.com/-HwQQd9-iXew/VrfV1_32vtI/AAAAAAAABkU/iypqd4V7KxA/s800-Ic42/DSC_0076.jpg

Notice that I've done the first stage of shaping the Braces on the left of the photo. You feel you could do with an extra pair of eyes, when doing this, as you have to chisel the Braces down to essentially nothing at either end, and I did slightly mark the Top when doing it for the first time.

ArchtopDave

https://lh3.googleusercontent.com/-d1XKYw3DHn8/VrfV6AY3PYI/AAAAAAAABkU/t8RS46aOahA/s800-Ic42/DSC_0082.jpg

The good news with this bit of shaping is that it actually gets easier to chisel through the wood as you steadily create more angle..

ArchtopDave

https://lh3.googleusercontent.com/-qCj1AKMnIaE/VrfV_oPWbHI/AAAAAAAABkU/IiDWu-EIpew/s800-Ic42/DSC_0089.jpg

The larger Lower Bout Braces are added, and the Braces around the Sound Hole.

ArchtopDave

Here's the ends chiselled down to meet the surface of the Top.

https://lh3.googleusercontent.com/-ruFYGnxKoOw/VrfWJHLVMBI/AAAAAAAABkU/lLK2aqhmUdY/s800-Ic42/DSC_0094.jpg

ArchtopDave

Then the sides of the Braces have to be shaped with the Finger Plane and Sand Paper.

 https://lh3.googleusercontent.com/-SH40w6lFYV0/VrfWMUnFknI/AAAAAAAABkU/xXGlnmUelCc/s800-Ic42/DSC_0104.jpg

ArchtopDave

A small detail, but the Brace nearest to the Neck has to have it's surface partially drilled to allow good access to the end of the Truss Rod.

https://lh3.googleusercontent.com/-kfSwl1D5tMo/VrfWMRTf3EI/AAAAAAAABkU/mZOxYVXty0o/s800-Ic42/DSC_0102.jpg

ArchtopDave

The main X-Brace is then glued in, and there's more shaping to be done.

https://lh3.googleusercontent.com/-PFAgIseD-RM/VrfWUCTg44I/AAAAAAAABkU/IE1koc83WRY/s800-Ic42/DSC_0106.jpg

Small reinforcing squares were glued down the Centre Line (these were prefabricated ones).

https://lh3.googleusercontent.com/-QUW4_BE20ks/VrfWWymANII/AAAAAAAABkU/7l1rOXqT-hU/s800-Ic42/DSC_0113.jpg

ArchtopDave

The X-Brace Joint needs to be made as carefully as possible so that it is a good tight fit prior to glueing. I hope you'll agree that I did a good job with this. Also you can see the side to side shaping of the Braces.

 https://lh3.googleusercontent.com/-F3hVvZzjgGc/VrfWXJpR2gI/AAAAAAAABkU/QxmBM5E8x1s/s800-Ic42/DSC_0142.jpg

ArchtopDave

The final shaping job on the Braces is to scallop them. There a process of initially scalloping them into shape, and then their final shape depends on assessing the Tap Tone of the Top, and scalloping a bit more to maximise the Tap Tone. You aim to hopefully get three distinct and different Tap Tones from different areas of the Top.

https://lh3.googleusercontent.com/-sqj0ElPQtTo/VrfWdY0kVLI/AAAAAAAABkU/dDVAknZwGVA/s800-Ic42/DSC_0144.jpg