Myrtle for Lute backs

Umbellularia californica is a large hardwood tree native to the Pacific Northwest, commonly known as Myrtle, California Bay Laurel, Pepperwood, or Myrtlewood.

Myrtle physical properties are similar to African Mahogany and is not listed in the CITES Appendices or on the IUCN Red List of Threatened Species.

While traveling through Oregon I stopped at a roadside shop specializing in beautiful decorative and functional objects made from myrtle.  Amazingly, they sourced all their wood locally and kiln dried in their own custom building.

I purchased a large plank of myrtle to experiment for lute backs.

Dimensioning and cutting the rib blanks was easy, with the band saw properly setup this is a pleasure.

I was able to get enough myrtle to make two complete 13 course baroque lute backs. 

The first myrtle set had a very straight figure and uniformity from rib to rib.

The resulting back was also very uniform and quite striking. 

I noticed a very slight yellow-greenish tint which I found troubling, and so I experimented with a darker stain. It produced a very pleasing effect.

The second set was rather wild !

Here is the completed lute.  I finished the instrument with true-oil.

A third and fourth sets of myrtle were cut from a board generously given to me by a violin maker and proved to be quite different from the first two sets.  I found these sets the most pleasing because the figure was interesting and the raw wood color very pleasing.

Working with myrtle was a joy. I found no particular issues cutting, sanding, bending, trimming or gluing.  As I remember the raw wood was very economical. 

With the right piece of wood, I would not hesitate to build more lute backs from myrtle.

Reinforcing lute ribs

Paper strips are glued to each rib joint as reinforcement.  This is an easy process.  First cut paper strips of the desired width.

Dry fit a paper strip in place to mark and trim the ends for a good fit.  I like to place a tab or two of tape as alignment so the paper strip remains centered on the rib joint when gluing.

 Apply the glue of your choice to the lute rib joint first – then align the paper – and apply a layer of glue on top of the paper.

 Smooth the glue and press the paper into the joint to get good contact and clean up the excess.



Experimental process follows…..
Once I dropped a completed Baroque lute shell before the top was added. The shell cracked and split for half its’ length….ouch!
It was obvious that the paper reinforcing strips had little effect on preventing cracks from propagating.
So, as an experiment here is a shell reinforced with woven carbon fiber composite instead of paper. I now use this technique on all my lutes.

Because the carbon fabric is woven you can’t just cut into strips – it will unravel.
However, it is easy to spray the fabric first with a clear lacquer or similar spray that holds the fibers together enough to cut into strips …. but still allows the glue to penetrate throughout the fabric weave.

Even though the fabric has been sprayed to prevent fraying, it is still very flexible.
Just use a straight edge to make the weave straight. Then cut a strip with a sharp knife.

Glue the carbon fiber strips as you would a paper strip.
I first made a test joint in this manner with two small pieces of lute ribs. There was no way to tear them apart.

The material I used was from Amazon:

5 ft x 12″ Carbon Fiber Fabric – Plain Weave, 3K, 220 GSM

Go here to get back to the workshop.

Assembling lute ribs

Since the ribs have been bent to the proper shape and edges trimmed to the correct angles, the lute back can be assembled with tape to hold the ribs together during gluing.

Once you get several ribs glued together, it’s easier to just continue to assemble “free-form” without the template. As each rib gets added, the bowl becomes quite stiff.

Oh what a messy glue job 🙂

After a little cleanup you can add the reinforcing paper strips, glue in the neck block and add the bottom reinforcement.

Go here to see how to make the neck block.

Go here to get back to the workshop.

Making Lute Ribs

The bending tool I use is simply a piece of 1 1/4″ galvanized pipe connected to an inexpensive heat gun. The right angle elbow on the end of the pipe helps restrict the airflow but also helps warm your toes on chilly days. The heat gun allows different heat and airflow settings so you can control the temperature of the bending pipe to suit the wood you are using.

I spray the sanded & final thickness lute rib with water and free-form bend the rib by hand enough so it can be held in the rib form as shown. Make sure to put a pencil mark on all ribs and a corresponding mark on the bending form so you can align each rib during bending. That way any wood figure patterns match from rib to rib. It’s easy to provide downward pressure on the form based on how the rib is “giving” to the heat. Rocking the form slowly back and forth assures that the rib will eventually assume the profile of the form.

Once the rib is close to final profile as seen below, I use the form to mark in pencil the rib outline and remove all the extra wood using the band saw. Then, repeat the wetting and bending process again with the rib close to its final shape. Since a lot of wood has been removed, it’s now easier to bend the rib accurately to its profile. If you prefer you can use the poster board rib template produced when you made the bending form to mark each rib and cut off extra wood before bending.

After the rib is bent, clamp it back in the form and trim the edges to smoothly match the form. Here I have shown a large spokeshave being used for the smoothing operation (I find it easy to use), but I’m sure any really sharp tool would work. The caution here is to watch the grain carefully and plane accordingly – or you can get splitting – which requires appropriate language to match the degree of splitting….

As the last step, I lightly hand sand each rib on a flat board with various grits of sandpaper glued to the board.

Here is a complete rib. Once setup, it takes just a few minutes to make a fully formed rib that is ready for assembly.

Go here to see how to assemble the ribs without using a mold.