Friday, 4 May 2012

Elephant No. 215: Compact Disc

Although I view CDs and DVDs as a necessary evil for work, I never know what to do with the ones that no longer serve any useful purpose. The idea of making a mobile with full-sized CDs, or using them as coasters, or snapping them into bits and making a mosaic just doesn't appeal to me. And it feels wrong to throw them out with the trash. So today I thought I'd recycle at least one by making an elephant of some sort.

An online search for ways in which to recycle CDs turns up all of the above projects in multiple iterations, along with similar stuff such as using them as a base for pillar candles, using them as reflectors for Christmas lights, and my favourite: "Put it in the microwave to soften it, then shape it into a bowl." To which someone replied, "And watch the CD create fireworks inside the microwave." Good thing I don't own a microwave, or I'd be tempted by that whole fireworks thing.

Compact discs evolved from LaserDisc technology, which was first demonstrated by Sony in September 1976. Two years later, Sony was showcasing a digital audio disc with a 150-minute playing time, and by March 1979, Phillips had produced both an audio disc they called a "Compact Disc" and the first "Compact Disc Audio Player". Although the commercial potential of the technology had yet to be proven, by 1980, an international Compact Disc standard had been established, including decisions on sampling frequency, playing time, disc diameter, and so forth.

The first test CD was pressed in Germany by the Polydor Pressing Operations plant in 1980, and featured a recording of Richard Strauss's Eine Alpensinfonie, performed by the Berlin Philharmonic. The first broadcast demonstration of the new technology came in 1981, when the album Living Eyes by the Bee Gees was played on the BBC television show, Tomorrow's World.

In August 1982, the true rollout of CDs began, first in Germany, then in other parts of the world. The first album ever to be commercially released on CD was 52nd Street by Billy Joel, which hit the market in Japan on October 1, 1982, along with Sony's first CD player. On March 2, 1983, CD players and discs—a whopping 16 titles by CBS Records—were released around the world, in an event that has since been dubbed "The Big Bang" of the digital audio revolution. In 1988 alone—a mere five years later—400 million CDs were manufactured in 50 pressing plants around the world.

Although currently on the decline due to the rise of digital downloads, by 2007 more than 200 billion audio CDs had been sold around the world: an average of more than 8 billion for every year since the technology first hit the market.

Each CD is made from a piece of polycarbonate plastic measuring 1.2 mm (0.047 inch) in thickness. A thin layer of aluminum, and sometimes gold, is applied to the plastic, making it reflective. The metal is then coated with a film of lacquer, followed by a label.

Layers in a CD: A—polycarbonate plastic; B—metallic layer;
C—lacquer; D—label. E—laser beam.

The data is stored in a series of tiny "pits" contained in a spiral track moulded into the top of the polycarbonate layer. The spaces between the pits are called "lands". The data is read by focusing a laser beam up through the CD from the bottom. The difference in height between pits and lands alters the way the light is reflected. A photodiode measures these changes in light intensity, and the information is converted to binary code.

Interestingly, damage to the label side of a CD is more problematic than scratches in the clear side. Because the pits are closer to the label, scuffs and contaminants on the clear side are more or less "out of focus" during playback. As a result, damage to the clear side can actually be repaired by filling in scratches and the like with similar plastic, or by carefully polishing the surface.

For today's elephant, it appeared that the easiest way to alter a CD was to heat it enough to soften it, followed by cutting and bending. Suggested sources of heat ranged from a heatgun to boiling water, to the less-benign blowtorch—which, someone suggested, is also likely to set the CD on fire.

I opted for boiling water as a starting point. Instead of a CD, I used an old DVD, mostly because I liked the purple sheen. This was from an old video project which has since been reproduced in multiple forms, so this little guy could be happily sacrificed.

I boiled an entire kettle full of boiling water, and poured it over the DVD. Nothing. It didn't soften the DVD at all. At all. I left it in the water for a good 20 minutes, then realized it was pointless.

Next I pulled out a heatgun—the heavy-duty kind you use to strip paint off wood. Surely, I thought, this will make the DVD turn to putty. I hung the DVD on a piece of wire to avoid burning my hands, and blasted it with the heat gun long enough that, if this were paint, it would be a mass of blisters.

Even this did very little. The heat made it slightly easier to cut into the DVD than if I had been completely cold, but it was still not soft enough to keep the edges from chipping and cracking.

Since I wasn't interested in trying blowtorches and the like, I made do with this shape. My idea now was to see if I could heat it enough to give it a small curve at the very least. No dice. What heating did this time was cause the layers to separate—probably because the various materials heat up at different rates.

At first I viewed this as a total disaster, and considered trying something else. Then I decided to work with what I had.

Given that the only obvious separation of layers was along the edges, my first brilliant idea was to glue things back together. Then it occurred to me that, since I'd already photographed it before it separated, it might be more interesting to peel the two layers apart and see what that did.

This turned out to be much more interesting. I now had two shapes: one with the metallic underlay, and one that was clear. Interestingly, both pieces have the same rainbow sheen. It was fortuitous that the one place where the layers stuck was around the eye area, although I'm sure I could never re-create that effect again. Another interesting thing was the way the metallic layer migrated and bloomed, making a sort of watery pattern in the clear elephant.

A few observations that may help if you decide to try this:

1.  Unless you want to use the clear ring and hole in the centre, you'll be limited to a relatively thin, curved area around the outside. I didn't plan my design ahead of time to take this into consideration, and I probably should have.

2. Although some online instructions warn of noxious fumes, I didn't notice anything—and I'm usually the proverbial canary in the coalmine when it comes to that sort of thing. Not that I always take the necessary precautions, but I do notice when there are noxious fumes in the air. It may be that I never reached the real melting point of the DVD materials, so if you can, definitely do this in a ventilated place, but don't get too stressed about it unless you're doing an entire production line.

3. Be prepared for cracks, particularly if you decide to cut curves or notches. The heatgun softens things to a certain extent, but the plastic hardens again almost immediately.

4. There are also some design-related properties of the DVD/CD material that you may want to consider: a) the metallic and lacquer layers react to one another when heated, forming interesting moiré and water-like patterns; b) the layers will ultimately separate if you continue to heat them, but not in a uniform way; and c) if you intend to separate the layers, remember that the main colour of the clear piece will be the same as the dominant colour of the non-label side of the disc.

5. Be prepared for things to be relatively random. As far as I can tell, there's no real way to manipulate the patterning in the various layers. I tried side-blasts of the heatgun, as well as blasts from the reverse and full-on from the front, and it made no discernible difference.

I can see trying this again with simpler shapes, and I would use the same heat gun process to make the layers separate. The two layers are virtually the same thickness, so you can use both. I'll probably glue a pin-back to the opaque one, and use the clear one in a window or something. Because the clear one has a bit of pattern in it, it actually casts interesting shadows, as well as colour.

I didn't love this process, mostly because it wasn't as straightforward as I wanted it to be. I wish I'd made a more exciting elephant outline, but in the end I rather like what I ended up with. It wasn't what I expected, but now that I know what I can do with this stuff, I will probably try it again.

Elephant Lore of the Day
Some people are just plain stupid when it comes to interacting with animals.

In May 1983, a man named John Marshall was visiting the Clyde Beatty-Cole Brothers Circus in Atlantic City, New Jersey. Somehow he got into the areas where the animals were kept, and decided he'd like to pet a lion. Circus employees understandably chased him away.

Marshall hid for a bit, then made his way to the elephant enclosure. Slipping inside, he approached an elephant named Frieda, picked up her trunk and blew loudly into it. Clearly appalled, Frieda grabbed Marshall with her trunk and tossed him across the enclosure.

Marshall suffered several broken bones and internal trauma, but survived. Frieda, quite rightly, was not punished for the incident.



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