Category Archives: engineering

CNC Bubble Iris Article Released
Photo of the CNC Bubble Iris taken at Autodesk’s Pier-9 facility by Nathan Hurst, Editor at Make Magazine.


It is a real pleasure to see Make Magazine,  Hackaday, and Adafruit #ArtTuesday all re-blog the publication of the apparatus I’ve built to bring new precision, repeatability, and automation to the craft of giant soap bubble making.  Stay tuned for all the interesting things I’ll use this instrument for!

Gordon Kirkwood Performs Solo Cello at Silicon Valley NewSpace Conference Black Tie Gala Award Ceremony

The Space Frontier Foundation’s annual conference is one of the most important commercial space conferences in the nation, and will be held July 16-18 in Silicon Valley.

Attended by the elite and rising stars of space entrepreneurship and the administrators of NASA, the FAA,  and the founders and directors of significant aerospace companies,  I am inspired and delighted to play to a crowd of rocket scientists at the culmination of such a conference.

Controlling Lightning Morphology around and within the Same Flower during Kirlian or High voltage Photography

Artocarpus Altilis - the breadfruit tree's leaf.  test shot - with a DSLR - taken just prior to the large format analog film exposure.
Artocarpus Altilis – the breadfruit tree’s leaf. test shot – with a DSLR – taken just prior to the large format analog film exposure.


I’ve been home for but a week, and tomorrow I set out on a grand adventure of driving crosscountry in wintertime for a yet grander adventure  as an artist in residence at the incomparable Autodesk Pier-9 workshop.   Before I go though, I wanted to upload a few of the digital test shots I made while in hawaii this last month, shooting “Electrified Flowers (and leaves) of Hawaii“.

These were off the cuff test shots – throw-aways – done to check my exposure, check the electrical apparatus,  and visualize the pattern of branching lightning that I might be about to record onto expensive 20-square-inch large sheets of silver halide and color film.   These are not the final products of my project, rather mere teasers of work-in-progress.   (I have yet to develop that film, which I’ll do once I can settle into San Francisco.)   However,  I’m pretty ecstatic with the results, sofar!

One of the most exciting learning discoveries for me during this work is that I can significantly control whether lightning issues radially from the leaf,  or tangentially skirting around it,   or some mix between the two.    I’m looking forward to making an excellent explanation of how this works,  both practically and in detailed physical terms.  It will probably be a chapter of the book I’m working on, “Theory and Practice of High Voltage Photography”.

Congea Griffithiana,  Pink Sandpaper Vine,  a.k.a. Shower Orchid.  introduced relatively recently to Hawaii.  From the Amy B.H. Greenwell Ethnobotanical Garden.
Congea Griffithiana, Pink Sandpaper Vine, a.k.a. Shower Orchid. introduced relatively recently to Hawaii. From the Amy B.H. Greenwell Ethnobotanical Garden.
Pink Sandpaper Vine
Identical leaf as above, taken within about 10 minutes of each other, with a minor but significant change to the charging circuit. Note how different is the form of the lightning!!





Gordon Kirkwood selected as Artist in Residence at Autodesk’s Pier-9 Dream-lab.

“Giddy” cannot begin to describe my feelings upon learning,  on Thanksgiving,  that I have been selected to be an Artist In Residence at Autodesk’s Pier-9 dream-lab  in San-Francisco.

The concentration of brains,  initiative, creativity, and capability in that space is stunning. In close approximation to Tony Stark’s workshop (from the movie Iron-Man) — a dream-shop with some of the most capable robotic fabrication equipment and tooling in existence including 3D printers, water-jets, lasers engravers powerful enough to work with metal,  multi-axis milling machines, and more — it goes far beyond simple awesome tooling to be, from what I gather, a collegiate atmosphere where everyone is extraordinarily motivated to learn, make,  and do things that push the limits of creativity, and in a context where the expected norm is to share and disseminate knowledge through the Instructables knowledge sharing website platform.  Buzz Aldrin (Astronaut of Apollo XI moon-landing fame and the second person to walk on the moon after Neil Armstrong) was hanging out there testing a functioning magnetic repulsion hoverboard a few weeks ago,  for instance.    To be included in the cohort of selected artists for 2015 is a huge honor and inspires me to the grandest ambitions.  Thank you,  universe.  Thank you,  Noah.  Thank you, Vanessa.  Thank you, Mary.  Thank you, Karen.

PIER 9 AiR PROGRAM from Pier 9 on Vimeo.

Computer Controlled Variable Aperture Soap Film Iris – First Bubbles!

I’m fascinated with ephemeral phenomena,  and the most recent manifestation of this has led me to invent some elaborate technical apparatus to make photographs of huge bubbles doing interesting things.  Here are two videos of it working for the first time- the first with a series of close-up views of different components, the second as a wide-view of the whole system in operation.

Giant bubbles are uniquely able to engage and delight people of all types.   Who can resist feeling wonder and awe at giant, floating, opalescent, undulating transparent orbs and the salience they give to normally invisible 3-dimensional flows?  After my first experience blowing bubbles from a moving bicycle (the wind past the bicycle removes any requirement to blow or move the wand, you just adjust your speed to get the right wind),   I was hooked.

I’ve organized a number of bubble blowing events,  especially the “Bubbles on Bikes Jamboree Ride” for Bike Pittsburgh’s Bikefest and the first ever “Giant Bubbles Flash Mob”.   For the latter, I manufactured 45 giant bubble wands,  and about 25 gallons of giant bubble juice,   and coordinated a synchronized release of ridiculously many   insanely huge giant bubbles.    Beyond the pre-arranged 45 bubble blowers,  we had the fully invested attention and participation of somewhere between 300 and 500 people for several solid hours.  All for about two days prep and maybe $200 in materials (including the pizza for the wand-making party).    See the nicely polished video made by Ben Saks of Float Pictures here,  or the great single-take cellphone video clip from Jason Kirin here.

For some things I’d like to do, I required a highly repeatable way of producing bubbles,  and controlling aspects like timing and size and speed and direction.  I also love a good engineering challenge,  and so I invented a cable iris aperture mechanism and set out to use it to make a uniquely flexible and useful bubble machine.  A CNC bubble machine.

There’s a few very sophisticated things I’d like to do with this which I’ll write about later, but for the first project I’m looking forward to making playful occupational portraits of some friends, mentors, and elders I feel lucky to know and learn from.  I’m fortunate to have a few such in my life,  in their sixties, seventies and eighties,  and who in addition to great technical accomplishments, embody wonderful spirits of playfulness and creativity in their golden years that it’d be my pleasure to honor and record with such portraits.

Where will you say you were when, at 10:40 EST, humanity first landed a probe gently onto the surface of a comet in deep space?

Can you fathom what it must feel like to be one of the astronomers who, 45 years ago, discovered a comet, and is here today watching as we as a species are rendezvousing with that comet, gently landing a 200 pound Philae probe onto the surface, while we watch from the orbiting Rosetta spacecraft 19 miles above?

This is so humbling and inspiring to witness. Congratulations to everyone involved, especially the engineers which, by the various slingshot maneuvers, accelerated this spacecraft so deep into space on such a perfectly accurate trajectory to hit a bullseye hundreds of millions of miles away!!

Watch this amazing animation of the incredible 12 year long, half-a-billion-mile, bullseye we will see stick it’s landing here in less than one hour!!

May your life be as smooth as Silicon-Bronze TIG brazing.

small heptagon with square tubing at 45 degrees from flat, after welding and wire brushing.
An experiment in jig construction, TIG-brazing, and symmetry. This took about an hour from conception to completion, much of which was locating the V-blocks for clamping the tubing at 45 degrees during cutting.
Small heptagon with square tubing at 45 degrees from flat, as tacked together, showing fit-up.
Tacked at ID and OD. The fit of the bevel cuts is sublime! not a sheet of paper could be inserted at ID or OD of any joint. Spot on 64.3 degree (=90-(180/7)) bevel!

Next step:  make four of these with the tubing’s face to table’s face angles sampling intervals of 0, 22.5, 45, and 67.5 degrees (or generally, angle increments of ([0:(n-1)]/n) * (360/(number_of_tubing_facets_equals_4_if_square_tubing)) degrees rotation from flat.   Make a jig to photograph them at consistent position,  then make looping stop motion animation of toroidal ring rotating around it’s minor axis…

Then,  perhaps, I will also incrementally crush each ring as I’ve done to destructively test prior similar experiments,  and register each frame,  so the animation might suggest continuation of the rotation throughout the increasing deformation.

Animated Retroreflective Safety Signage

I’ve been playing with a new process in which I remove the silvering of mirrors in detailed patterns,  leaving optically clear glass.

A zone plate made of mirror and optically clear glass zones will focus images in both reflectance and transmission.  The focal length of this plate, at visible wavelengths, is too long to be practical though.  I'm experimenting with shorter focal length, finer ring spacing, zone plates.
A zone plate made of mirror and optically clear glass zones will focus images in both reflectance and transmission. The focal length of this plate, at visible wavelengths, is too long to be practical though. I’m experimenting with shorter focal length, finer ring spacing, zone plates.

My first experiment was to make a Zone Plate,  but my current process didn’t have enough resolution to make fine enough lines for a zone plate of short focal length at normal visible wavelengths around 600nm:

However, the process is fantastic for barrier grid a.k.a. moiré a.k.a. ‘strip’ animations,  and for an afternoon project this has borne incredible fruit:  only about a dozen promising directions to go from here!  I decided to focus first on making an animated cautionary text and moving image safety sign for vehicles, especially bicycles,  especially helpful for night-time visibility.


US Patent #8154279 Issued To Gordon Kirkwood &co. for Non-Destructive Magnetic Sensor of Graphitization Corrosion

Grey Iron and Ductile Iron Pipe are the dominant conveyances of water and sewage in American infrastructure.    These types of iron have carbon and iron constituents whose relative distribution and crystal sizes determine their mechanical properties.    Over time,  this material are susceptible to ‘graphitization corrosion’ in which either graphite particles migrate and aggregate (typically at temperatures above 800F)  or in which local electrochemical corrosion at room temperature results in preferential loss of the iron / ferrite constituent of the matrix. When this happens, the pipe becomes brittle, and mechanical insults like vibration  or thermal stresses can exceed the flexibility of this now brittle material,  leading to brittle failure and cracks. However, this corrosion can be invisible,  because the remainder graphite particles are cohesive and the pipe appears physically unchanged.

Illustration from the patent, indicating changing composition of portions of a grey iron pipe wall, in cross section.

During road work, construction, and maintenance operations, these pipes are visually inspected,  but because pipes experiencing graphitization corrosion often look physically unchanged – the graphite material remains in the same contour as the original material,  a method of detecting the change in properties of the pipe was needed which did not depend on visual changes, or subjective “bang on it with a hammer” subjective methodology,  as was the state of the art previously.  We needed a non-destructive method of detecting the changing properties of the pipe.

The insight of this patent is that the changing microstructure of the graphitized material has reduced magnetic properties due to the loss of iron.   This could be sensed by measuring the magnetic permeability of the pipe,  or it’s consequential magnetic measurements like inductance or the force developed within a fixed magnetic field.   At the urging of my mentor Dr. Mehrooz Zamanzadeh,  President and Principal Scientist of Matco Services,  and with my assistant Sam,  I developed a prototype sensor and confirmed that magnetic flux concentration,  magnetic force, and inductance measurements are all viable methods of non-destructive detection of changed microstructure and ferrite loss in grey iron and ductile iron pipe.     US Patent 8154279 was issued on April 10th 2012 for “Non-destructive testing apparatus for the detection of graphitization of iron”
US08154279-20120410-D00004 US08154279-20120410-D00005