Portland Guitar Brazilian Rosewood Sister OMs

[Portland Guitar]

Hello Everyone! We are back with a new build. The last couple were successful, so Jay has decided to make a pair of Brazilian rosewood OM’s. The goal for these two are understated elegance. One way he will achieve this is to give all edges a border. Jay has around ten Brazilian rosewood sets, he stocked up on them eight years ago. This first post shows the woods that will be used and starts to get the neck. Let us jump into it!

One set of Brazilian rosewood.

The second set of Brazilian rosewood.

Snake wood binding.

The complete set of wood used for one of the guitars. The plan is to use a cedar top.

For the second guitar

Adirondack spruce top for one.

This is a piece of high quality khaya mahogany.

Amboyna burl for the headstock

Neck blank in the cnc.

Two necks after they have been through the cnc.

The headstock.

[cigarfan]

Beautiful woods! Will be fun to follow.

[Portland Guitar]

Hello Everyone,

Amidst the social distancing there has been lots of time to work on these Brazilian rosewood OM guitars. With the woods picked out Jay moves on to the neck. We do most of the heavy lifting on the CNC. We get the shape of the neck close to where we want and then go in with the orbital sander to finish up. The artistic goal with these necks is to use binding on the fretboard and headstock with inlay. There is a lot of detail and attention paid to the setup of the CNC to ensure that the right channels and shapes are routed.

To make the top level the board is placed in a clamp and two machining plates with magnets underneath are used to make sure it is flat. Then a planning bit goes over it to make it absolute flat and even.



Here is the neck after the CNC has routed out the top. We need to leave a tab between the main piece and the edge so the clamp can keep everything down without the center flying out.



Here is the back of the neck after the CNC. we are use double stick tape to hold the top to a spoil board.



The CNC also does the sides of the heel block.



Special channels are routed for the neck hardware. We use a bolt on neck which allows for the use of the easy adjustable cantilever. A bolt is fixed to a barrel bolt in the center channel to allow for a tight joint.



A plate is put in a channel at the heel which adds some extra support for the fretboard.



The fretboard is epoxied on and there is inevitable squeeze out.



Amboyna burl is used for the headstock. It is place in a vice with the top piece strategically placed above the clamp.



pockets for the inlay are routed and then a medallion is placed inside after binding is added. This is a closeup of the 1/2inch router bit carving the pocket.



Completion of the fretboard. We can get the radius and slots done in this step. This creates an exact and even radius that we can easily change for one job to the next.



Jay getting his sand on.



The fretboard in the process of being fretted.



The finished headstock



the necks

[Portland Guitar]

Welcome to the third post following the journey of these soon to be Brazilian rosewood guitars.
It is time to turn a few pieces of wood into a curvaceous body. This is a much less CNC intensive process, we use it slightly for the top and to join the back.
The main tools we use to get the shape of the woods right are a fox style bending machine and a go-box.
The Brazilian rosewood has a rich smell that is delightful to work with. We are excited to hear the first sounds!
To get a precise join both pieces of the back or top are placed in a shooter board then a ¼” bit runs down the side.
The CNC has to movie in a straight line, so it gives us a clean, flat and straight surface.
This makes for excellent joins.



The CNC routing out the rosette and pin holes. We do not cut the final shape here because it’s useful to have extra space when placing the braces.



Amboyna burl is used for the rosette and a black white black border frame it.



The side before it goes into the heating blanket. A few layers of aluminum with a heating pad run the length of the side.



Into the bend-o-lator.



Bent curfing. Easy compared to other woods. Fun to play with. So bendy.




The curfing gets glued into the side with wood glue and clamped on.



After the glue sanding must be done to eliminate the squeeze out. Even though no one will see it, It is important to Jay.



To glue the sides together a heel block and tail block must be used so the sides have something to attach to.



A completed and incomplete frame. In the top left are both blocks used.



Jay at work sanding the frame. The edges must match the curvature of the top and back, A board that matches that curvature is inset in the board so that the frame can be sanded to fit.



Love during the build makes the guitar sound better.

[Portland Guitar]

The sides are together, and the frame is complete.
The next thing to do is prepare the top and back then glue them together to complete the body.
Both are coming together quickly. Pretty soon they we will be able to hear how the body sounds.

The Adirondack rosette of amboyna burl inlayed in three spots.



The braces are placed on the top and adjusted until in the right place.



They need to be trimmed to their final size before they are glued on.
Then they are glued down using a radiused bowl that sits in the go-box.



Post-glue



The braces will be sanded down to a smaller size with the orbital sander.



Jay cleaning up some glue on the tail piece.



The back and top are aligned on the frame.



The body is glued together. Jay finds that tape is enough tension to make a tight fit.



The neck bolt holes and cleaning up the pocket.



Cleaning up the edges.

[Portland Guitar]

These guitars are getting closer and closer to getting the strings on hearing their sounds.
The next steps are to put in the binding and purfling. Ivoroid and snakewood are stacked on top of each other for the binding.
The purfling is going to be Jay’s wave design with the negative area filled with a pigmented epoxy. It is a challenge to get the waves to line up were the meet at the top and bottom.
It depends on the total length of purfling needed and can be varied with the size and spacing of the waves.

It appears I've been uploading images in a roundabout way, I hope these are correctly sized. It looks like after the site migration all my pictures are too large.

Let me know if you have any questions or comments!

The channels are routed for the binding and purfling. The machine used is a movable arm with a router mounted on top. With the guitar on a lazy susan it makes traveling the outer edge easier.

purf wave and peak-10.jpg

The waves are routed out in the CNC. It’s simple to do these in bulk. The waves are held down with double sided tape. Care must be used when prying them up or they will break. They are heated up to loosen the tape then removed from the spoiler board with a chisel.

purf wave and peak-06.jpg

One of the waves. The fuzziness must be cleaned up before use.

purf wave and peak-07.jpg

The waves are glued into the inner edge next to the wood. This creates a nice well for the filler. The overhang needs to be clipped off.

purf wave and peak-11.jpg

A black pigment is mixed in with epoxy to create a filler. The popsicle stick is a great for spreading.

purf wave and peak-02.jpg

The pigment is spread in. Unless the perfect amount of epoxy is used there is always cleanup.

purf wave and peak-03.jpg

It can get messy. The excess needs to be sanded away, without sanding through the waves or creating gaps with the wood.

purf wave and peak-05.jpg

The red on black on white is distinct.

purf wave and peak-04.jpg

Finished.

purf wave and peak-01.jpg

Complete with the neck on.

purf wave and peak-09.jpg

purf wave and peak-08.jpg

Since the bodies are together, we can hear what they will sound like. The resonant tones do affect the sound slightly. We don’t draw many insights or use this to influence the build. I think it’s fun.

[Portland Guitar]

We’re ready to start finishing! These are getting closer and closer to hearing and seeing their final form. An airbrush is used to spray water born ploy urethane onto the body and neck. The thickness is thin to ensure maximum responsiveness of the top. The finish is sanded and polished until it shines. This is a difficult process that is easy to mess up with too much sanding or too thick of coats.

Here is jay spraying a coat onto the body. It’s held on a Popsicle stick so it can be rotated easily.



The finish is sanded off at progressively higher sandpaper grits.



The coat must rest before sanding. The amount of time the layer cures for is important. The longer it’s left the harder and more difficult to sand it gets. We opt for a lot of thin layers sanded quickly between them.



after the final coat is applied the body is sanded at a high grit and polished on the buffer.



The bridge is glued on. But first a wood surface must be cleared on the top. An exacto knife is used to score the finish. It is taped off to make sure the rest of the body isn’t hurt.



The bridge is glued on


the nut is made



These are done for the neck and both guitars and know they are finished.



Next will be the final pictures

[Portland Guitar]

They are finished! Here are a video, sound sample and pictures. We aren't the best players, I hope these suffice. I plan to make some better sound samples soon.

[Portland Guitar]

[prusaw]

Stunning!!! Can't wait to play them on friday