Materials and Methods, Pt. 1: The Viola Bow Charrettes
Wood
In the first unit, we learned about organic base materials such as woods, fibres, textiles, and naturally derived compounds. Along with a lecture on this topic, the class took a field trip to the lumber processing facility of Horigan Urban Forest Products, Inc. There were got a closer look at a common material that was enlightening for all.
For this – and the following units – I concentrated on making meaningful improvements to the viola bow, an object I am intimately familiar with. A thing I have learned in my years playing stringed instruments is that it always becomes less comfortable to hold a bow the longer you hold it. So, my first bow was an exploration into how to make the gripping points more comfortable to hold for a long period of time.
My normal concert bow
I began exploring this by using modelling clay to derive contours that complement the finger placement that most are familiar with. Then I transferred this information onto paper and used it to concept different bow forms. I found resources how traditional bows are made and augmented the method to result in more mass on the frog so that I would have material to remove. Finally, I used a rotary tool to remove material to produce contours like the ones in the clay.
Marking stick with finger positions.
Testing ergonomic shapes with clay.
Creating a bow and gluing extra wood to later carve.
Shaping and beveling bow.
For a prototype, this was successful in improving the overall comfort of holding the bow. Moving forward, I would procure Pernambuco wood (the traditional wood for bow making) and horse hair, and then produce a functional prototype to test comfort over a prolonged playing period.
Prototype uses additive wood processes on top of the conventional subtractive.
Metal
The second unit was focused on metals. These are chemical elements that are typically solid, good conductors of heat, and malleable. We visited Marco Lighting, a company that specializes in fabrication of light fixtures using sheet metal. There we gained an understanding of the versatility of metal through just bending, cutting, and welding. We learned more manipulation processes – such as casting, extruding, and electroplating – during our subsequent lecture.
For this unit, I sought to deal with some irony (pun intened). I wanted to make a bow out of metal that was lighter than a bow made of wood – the irony being that metal is simply far more dense than wood.
Anatomy of a bow.
I researched bow forms and drew inspiration from baroque bows, the predecessors of the contemporary bow. These bows were not curved and instead received tension by attaching the removable frog past the slack of the hair.
Baroque inspired sketch.
Inspired by this design, I procured a quarter-inch aluminium-titanium alloy tube and a two-inch cube of aluminium to fabricate my model. I cut the tube with ease. I struggled to make it through the cube, and after a few passes I gave up and made the frog and head out of wood instead.
Failed aluminium block.
Substituted with wooden frog.
Weight of normal concert bow.
Weight of aluminium bow with wooden frog.
To my surprise, the aluminium bow was almost as light as my concert bow. This means that going forward, a full aluminium-titanium alloy piece would achieve the goal of being lighter than a traditional bow. But first, I need to find a different way to make those parts.
Polymers
In the third unit of the course, the subject was polymers. While the commonality between them is hydrocarbons, these materials in many different forms. From the frail and brittle, to the bullet proof, polymers have a variety of characteristics that make their application nearly limitless.
Due to the versatility of polymers, I decided this would be the best category to test materials on a problem with only one clear solution.
When playing the viola (or the violin), one may need to play notes that are so close to the musician’s face that the fingers pressing the note are then obscured by the bow. So, for this unit I asked, “what if a bow were see through?”
Sketches of plastic bows using detachable strings.
To start, I selected clear cast acrylic as my material and laser cutting as my method. I explored forms inspired by medieval bows and used a detachable frog system similar to the previous project. I cut three styles out but broke one. I adhered the remaining two together with some string.
Laser cutting acrylic bow.
Prototype snapped.
Assembled poly-carbonate bow.
Given the breakage of one of the bow styles, I decided to test the flexion of the acrylic pieces to get an idea of how much stress they could take in comparison to the normal concert bow. While none of the bows were weighed down to such a degree that they broke, the acrylic bows were able to take more weight than was applied to the wooden bow.
You can see your fingers through the bow!
Maximum pressure that can be applied to concert bow.
Acrylic bow.
Poly-carbonate bow.
It appears that the broken piece was a design flaw as opposed to a material flaw. The current prototypes are heavy, so reducing weight would be a good next step. This could be done by testing a thinner piece of acrylic and a thin piece of poly-carbonate.
Ceramics
In the last charrette of the semester, the focus was ceramic materials. We discussed the way in which different elements are combined and fired to form various types of ceramics such as glass, porcelain, and common earthenware. We also took a field trip to Kohler and saw how the company was not only producing ceramic pieces but using ceramics to enamel metal as well.
A discussion during the previous critique and an encounter with an old party trick earlier that month lead to my exploration in resonance for this unit.
Imagine a D-sharp.
When ceramics are fired, their atomic parts restructure themselves and ideally form crystal chains which give fired ceramics their strength. This crystal structure also plays a role in the object’s resonance. Resonance is when sound-waves reflect within an object, increasing the signal strength (sound). The alignment of the crystals in ceramics can affect how sounds waves reflect off of, through, and within the object.
To test this, I played frequencies common for a viola out of a powerful speaker and I listened to see how many frequencies in this octave resonated within a given object.
I tested my viola, bow, solid and hollow ceramic and glass tubes, and my previous prototypes. I found that while the regular viola bow resonated with 5 notes, the glass tube resonated with 7. The aluminium bow also preformed well, resonating with 7 notes.
Bow sketches
Moving forward, this test should use more sophisticated equipment – such as an oscilloscope. Furthermore, different gauges of tube with different wall thicknesses should be tested to find one with resonate frequencies that directly match the viola itself.
