Ancient Friend

Ancient Friend
fused glass & metal, 2010

August 5, 2021

Fused Glass Bell Plates

During summer 2018 I had an amazing opportunity - I was invited to install my glass artwork at Filoli, a historic home and garden near Woodside, CA, along with three other glass artists, Cristy Aloysi and Scott Graham of Viscosity Glass , and Kim Webster, the Glass Gardener, for three months.   Since the exhibition was entirely outdoors, I designed for outdoor durability and for imagery and colors that would stand out against a busy and colorful garden background.  One of my projects, I knew, would be a glass instrument for visitors to play.

In this post I describe my approach to creating a musical instrument made with fused glass.  I had long ago noticed that a hanging panel of fused glass could make a pleasing sound when tapped (or hummed to).  During the DoonArt Open Studios Tour in July 2017, I demonstrated and discussed this with Martin Gaskell, an astrophysicist who is also keenly interested in all things musical.  We talked about the possibility of making fused art glass panels that would be in tune, musically speaking.  We made some sound recordings and later in the summer, Martin taught me how to use free software called Audacity to analyze the frequency spectra produced by my art glass panels.  This allowed me to begin testing, first with plate glass (cheaper), and next with fused art glass, to determine empirically if the laws of physics that govern acoustics function predictably in my art glass world (they do).  Specifically, I was interested in finding the relationship between the size of a square piece of glass and the resonant frequencies (musical notes) it produces.

As I learned while auditing Martin's class on Physics and Psychophysics of Music at UCSC during Winter quarter 2018, for a square plate, frequency is inversely proportional to the area of the square.  Frequency is also proportional to the thickness of the plate.  Thus a tiny change in thickness will have a greater effect on the pitch than the same tiny change in the length of the side of a square.  A simple way to put this is as follows, where f = frequency, L = length of a side of the square and b = thickness.

 and f is proportional to b

This can also be stated in a simplified equation:

f is proportional to b over L squared, multiplied by the square root of G, where b=thickness, L=length and G=shear modulus

This means that for bell plates of the same thickness and material, a larger plate will have a lower frequency (lower value of Hz) than a smaller plate.  And, for plates of the same L, a thinner plate will have lower Hz than a thicker plate.  The latter makes sense if you understand that stiffness is a factor in sound generation; a thicker plate has less flexibility and therefore, higher pitch. 

Back to practicalities: it is easier to cut glass in squares of different sizes (L) than to grind identical squares to very slightly differing thicknesses (b).  I prepared some test panels and graphed the inverse square root of the frequency (1/√f) vs. length (L) of my test panels in Excel.   I used the slope of the resulting line to calculate the L needed to obtain a desired frequency.  This would be very predictive if the glass was all the same thickness, as with plate glass.

Unfortunately, I discovered that the art glass I am using varies considerably in thickness, not only from sheet to sheet, but also within one sheet!  Thus I had to settle for cutting the glass close to the correct size and using a diamond coated lapping wheel to grind the edges of the fused panels until they were in tune, as shown below.

This works fine if the pitch is a bit flat, so I erred on the side of too large rather than too small - it's not possible to add a tiny bit of glass if the pitch is sharp!  Due to the variation in thickness mentioned above, some panels ended up as much as 13 Hz below the desired pitch. This can take hours to correct by grinding, since I needed to stop and check the pitch frequently so as not to remove too much glass.  Sometimes I was lucky, and the actual pitch was very close or identical to the pitch predicted by my graph.

Here's a short video of the square plate glass test series:

And a short video of my fused art glass test series:

Here's the finished octave, tuned to the key of A major (equal-tempered scale), installed at Filoli.

November 12, 2017

Local Craft Fairs I'll be in this Fall

I will have candle screens, small fused glass panels, glass bead earrings and beeswax candles.

In mid-November, at the Felton FireHouse

Santas Shelves 2017 qtr ad.pdf

In mid-December, at the Seymour Center in Santa Cruz

Jingle Shells Arts & Crafts Fair flyer

Sun. Dec. 10th, 12 - 5:30 pm

For more information, please visit this link

Flowers In Our Hearts

Aqua Tree Spiral II

An exhibition of new work at Viscosity Glass Gallery in Boulder Creek, November 2017

Viscosity Glass Gallery, 13158 Central Ave (also known as Hwy 9), Boulder Creek CA
Fri. 1-5 pm, Sat & Sun, 12-5 pm

June 30, 2017

Palo Alto Clay & Glass Festival - it's our 25th year!

Visit me in booth #51 at the Festival on Sat-Sun, July 8-9.   I'll have new fused glass tree, spiral and flower panels, candle screens and glass bead earrings.
We have really good food trucks & ice cream too 😋
Free admission and free parking.
Bring your sunhat and a water bottle, it's usually pretty hot in Palo Alto in July!
For more information, please visit: Palo Alto Clay & Glass Festival
Follow the Festival on Facebook: ClayandGlass

November 19, 2016

Light in the Trees

Announcing an exhibition of my fused glass and metal art at Viscosity Glass Gallery in Boulder Creek, Nov. 6 - Dec. 31st.  Join us for the opening reception on Friday Dec. 2nd, 6-9 pm, during the Boulder Creek Art Walk.

The gallery is located at 13158 Central Ave. and is open Fri - Sun, 12 - 5 pm for the season.

Viscosity Glass Gallery

July 4, 2016

Palo Alto Clay & Glass Festival

July 9-10, 2016, 10 am - 5 pm

Visit me in booth #58, along Embarcadero Road.  I'm bringing my new "Leaf Spiral" designs and some mixed metal samples, as well as the ever-changing candle screens, and earrings.

Admission is free; street parking and valet parking available.

For more information, please visit the Festival website.

December 9, 2015

KPFA Winter Crafts Fair

Sat-Sun Dec. 19-20, 10 am - 5 pm. 
Admission $12 (18-64), senior/disabled $8, youth free

This is the second year we will be in the Craneway Pavilion in Richmond on the waterfront, a beautiful setting.  Please visit me in booth #713, I have a window booth with a great view!
Parking is free, or you can take a free shuttle from BART.  For more information, visit this link: KPFA Winter Fair 2015