Main Body Parts:
clear cassette tapes sealed with screws
7/16th in dowel
paint (enough to make the box and dowel the same color)
picture hanging hardware
scrap piece wood
3m el wire 3m any color
battery-powered el inverter
small philips screw driver
drill and drill bits
hot glue gun
Optional Parts and Tools:
Step 1: Cassette Preparation
Using a small screwdriver, free the two sides of the cassette from the inner guts. Do not lose the screws.
The EL wire should fit easily within the body of the tape but prolly won't pass through the lower channel where the tape read head would be. Use pliers to pick off pieces of plastic until the wire will fit through. See the third image.
There also needs to be a path for the el wire to enter the back of the cassette. For this, use a small hobby saw and pliers to cut a chunk out near one of the round openings. A small knife may work as well, but be careful as styrene plastic is brittle and will crack. Be sure only to do this to the back of each cassette.
Optional Step: Removing the cassette labels
I intentionally picked bad music so the labels had to go. There are a few ways to do this but I settled on scuffing the labels off then polishing the plastic. Scratch the tape with 000 steel wool or progressively fine grades of wet sandpaper (400, 600, then 1500?).
Afterwards, the surface of the tape will be dull and opaque. See image 5. Use plastic polish to brighten it up. I used a Flitz branc polish which looked and smelled like toothpaste. Instructions on the bottle will probably include: clean, apply, polish with a cloth, repeat.
Step 2: Shadow Box
Sand the dowel with some course paper so that it fits easily in the cassette reel holes, then cut it into 1.5" lengths with a small saw or knife. Two of these nubs will hold each cassette in place. This is a good time to paint them the same color as the box.
Make sure the dowels still fit within the cassette holes, then epoxy them into each cassette. See the 3rd and 4th images. Be sure to only glue the backs so you can still open and feed el wire into each tape.
Epoxy the tapes with dowels to the box. Some masking tape might help in aligning them.
Remember the notches cut out of the back of the tapes? Drill through that notch and into the wood, creating a hole large enough for the el wire to pass through.
The last two images show one mounting option. Attach mounting hardware to a block of wood and epoxy it in place.
Step 3: Electronics
Continue to tack down the wire as you spiral it around the wooden dowels. Be sure to spiral the right direction.
Once one spindle is full, feed the wire through the bottom channel and to the next spindle. Eyeball the length and but the wire with a pair of wire cutters. See the 3rd image. If you are working with the el wire illuminated, be sure to turn it off before cutting it. Continue as before to finish it off, being mindful of the direction again.
When done, screw the cassette covers back on. Hot glue the battery pack in the back, trying to maintain a good center of balance. Tack down anything loose in the back while the glue gun is still hot. Done and done!
Step 4: Optional: Power Switch
These steps are optional and require some electrical and soldering experience. It applies only to one model of transformer so be prepared to improvise.
Take the batteries out of the transformer and flip it over. The silver sticker hides a screw. Take the screw and then the cover off, exposing the electronics. Wiggle the circuit board a little until it comes out.
Flip the board over and inspect the two pairs of terminals on the power button. Using a meter or following the traces, determine where to attach the two wires for the external switch, the solder them in place. The 4th image shows how this might look.
I used a male/make connector in the middle of the wire. This both made it easier to mount the switch and allowed for a quick disconnect to prevent packing material from turning the wire on.
Attach the button to the box in the typical fashion. This usually involves drilling a hole, fitting the switch through, and tightening a nut.