Subject: [7-8] How do CD-Rs behave when microwaved?
(2001/09/19)
Disclaimer: I'm not recommending you put a CD into a microwave. CDs may contain metals that will cause your microwave to arc, destroying the microwave emitter (see cautions about metal objects in the manual for your microwave). Don't try this at home. Better yet, don't try this at all.
The basic process is, take a disc that you don't want anymore, and put it shiny-side-up on something like a coffee mug so it's nowhere near the top, bottom, or sides of the microwave. (Actually, you may want to leave it right-side-up if the disc doesn't have a label, because the foil is closest to the top of the CD.) I'm told it is important to put something in the cup to be on the safe side, so fill it most of the way with water. Try to center it in the microwave. Turn off the lights. Program the microwave for a 5-second burst on "high", and watch the fireworks.
Performing this operation on replicated CDs results in blue sparks that dance along the CD, leaving fractal-ish patterns etched into the reflective aluminum. For those of you not with the program, this also renders the CD unreadable.
Trying this with a green/gold CD-R gives you a similar light show, but the destruction patterns are different. While pressed CDs and CD-RWs don't develop consistent patterns of destruction, CD-Rs tend to form circular patterns, possibly because of the pre-formed spiral groove.
On a different note, CD-Rs seem to smell worse, or at least they start to smell earlier, than pressed CDs. The materials used are non-toxic ("cyanine" comes from the color cyan, not from cyanide), but breathing the fumes is something best avoided.
For the curious, here's a note about why they behave like they do:
"The aluminum layer in a CD-ROM is very thin. The microwave oven induces large currents in the aluminum. This makes enough heat to vaporize the aluminum. You then see a very small lightning storm as electric arcs go through the vaporized aluminum. Within a few seconds there will be many paths etched through the aluminum, leaving behind little metalic islands. Some of the islands will be shaped so that they make very good microwave antennas. These spots will focus the microwave energy, and get very hot. Now you will see just a few bright spots spewing a lot of smoke. The good part of the light show is over, turn off the oven.
I suspect that if you leave the oven going much longer, the CD-ROM will burst into flame. This will smell very bad and may do bad things to your oven and house. Don't do it."
-- Paul Haas (paulh@hamjudo.com), on
http://hamjudo.com/notes/cdrom.html
Dreamcast GD-R discs come out just like CD-R, but DVD-R is a whole different experience.
Combining a microwaved CD-R with a tesla coil produces interesting results. See
http://www.electricstuff.co.uk/cdzap.html.