Watch the video to see waves of beautiful colors blending and sliding into a colorful vortex (first 2 minutes). The remainder of the video explains how to build one.

With just 2 CDs and a flashlight, you can create beautiful mesmerizing rainbow patterns. I saw a demonstration that used a single CD and I absolutely loved it. I then added a second CD and it blew my mind. It felt like I was being pulled into a vortex of color. I've never seen anything like it. I originally designed this contraption to create psychedelic Alice in Wonderland cat eyes for Halloween, but my kids would rather mask out the bottom of the eyes to create a more spooky face instead. It's also great for parties and festivals.

The device makes it easy to swap CDs for quick experimentation. A written CD looks different than a blank. And even different blank CDs will vary. The mesmerizing patterns are created by simply sliding the light and CDs on the rails. The build uses cheap hardware store materials, but is still robust and precise.

Supplies

Purchased Materials:

3' of 1/2" threaded rod $6, 4x 1/2" nuts $2
small machine screws $3 and nuts $3
18" of ¾" straight PEX pipe $4
3' of ½" straight PEX pipe $2

Common/Scrap Materials:

2x CDs with clear cases
bit of plywood ⅜" or thicker
14" of 3/4" thick wood at least 2" tall
4" of metal strapping
Packing tape & hot glue
4" of thin material like vinyl siding

Tools:

utility knife
drill press, countersink bit
hot glue gun
screwdrivers, pliers, measuring tape, square
safety glasses

Step 1: Create Clear CDs

Make a small slit right at the edge of the CD and then use packing tape to remove all the reflective surface. Don't worry if there's a bit of residue or scratching - it's just character of the disc and will make different patterns. You can use rubbing alcohol, don't overdo it - it will dampen the colors. You can also use a DVD disc if you carefully split it with a knife.

Step 2: Create the Base and Rails of the Slider

Drill two ½" holes into some ¾" wood pieces. Center the holes 3.5" apart. Cut the threaded rod to 18" or more and cut the ½" pex 2 ¼" less than the threaded rod length. Slide and rotate the threaded rod into the pex. The threaded rod gives strength and precision while the pex gives a uniform low friction surface. If you cut one piece of pex short, add a washer. Insert the exposed threaded rod into the base plates and fasten with ½" nuts. Tips in annotations.

Step 3: Cut the CD Sled Platform

Separate a CD case into three parts. Cut the bottom case layer to 3" wide measuring from the hinge pivot side. I'd recommend a chop saw or utility knife. If you use a chop saw, go real slow and flip the CD case around before cutting through the plastic against the fence to prevent a bad split. Trim the melted plastic with a knife.

Step 4: Create Sled Skis

Measure and cut 2 pieces of ¾" PEX to 3". These will become the CD sled's skis. Make a mark a ½" away from both ends. If you can, make your marks along side printing on the tube to help with aligning your marks. Then use a scratch awl or center punch to prepare for drilling with a ⅛" bit. Drill out the marks.

Use a utility knife to cut out the bottom 3rd of the sled ski opposite the drilled holes. Watch for knife slips and trim if needed.

Flip the sled ski over and counter sink through the pilot holes from the inside. Spend extra time here so that after you insert screws into the counter sunk holes, the threads will be close to perpendicular to the pex body. You also want to make sure that the screw heads are recessed so that they don't rub on the red pex rails. Push both skis onto the pex rails. Initially the skis will be loose on the rails, but they will tighten up in around 20 minutes. Tips in annotations.

Step 5: CD Sled Platform

Square up the sled skis then place the sled platform on top. Use a speed square to check that the platform is centered. The rail to platform edge distance should be the same for both sides.

Scratch each hole's center onto the platform. Fully support the platform to prevent it from flexing during drilling. Drill slowly!!! I tried going moderately fast one time and the plastic split and shattered very badly. Insert the machine screws into the counter sunk holes and tighten on the nuts.

Place the skis back onto the rails and then secure the platform onto the rails with more nuts. You can oversize the platform holes if needed. If the nuts aren't sitting flush, you can insert a rubber band piece as a washer to prevent cracking the platform.

Step 6: Making the Hinged CD Support

The video is really helpful to watch for this section.

Re-attach the CD case top layer. Bend one end of the copper wire into a hook and check that it fits into the preformed CD case slot. Remove it from the slot and then make two bends that will transition the copper wire from the outside of the case towards the end nut. Finally, bend an L angle opposite the hook end and trim it so that the L can slide on the platform past the end nut.

Step 7: CD Case Hinge Tilt Adjuster

Cut out a piece of vinyl siding J channel with the slot. It doesn't need to be vinyl. Any thin strong material that hot glue sticks to will work. Trim the piece so that it fits alongside the platform lip when the bolt is in the channel. The vinyl should slide freely back and forth.

Ensure the hinge is perpendicular to the rails. Move the vinyl ¼" away from the edge of the platform and tighten in place with a nut. This will later allow the hinge angle to be adjusted in either direction without the vinyl protruding past the platform. Lay out a bead of hot glue over the flat part of the copper onto the vinyl. After about 30 seconds, rotate the copper enough to break free of the hot glue bond. The copper will be held in place, but rotate freely.

The copper hook in the preformed slot needs to restrained. Squirt in some hot glue and rotate the copper wire slightly while the glue dries.This will hold the hook in place, but allow rotation.

Step 8: Cutting Out the Disc Grippers

Place the CD jewel case middle piece flat and score multiple times around the disc gripper on both the front and back side. Use garbage discs to prevent the case from flexing and cracking while scoring the back side. Use pliers to wiggle and snap along the score lines. Repeat until you have just the circular gripper. Trim any sharp edges with a knife.

Step 9: Attaching the Grippers

On the inside of the hinged case piece, temporarily tape on a disc where you want it to serve as a guide for alignment. Then on the case outside, place double sided tape around the inner circle. Insert the disc gripper into a clear CD, line up with the disc on the other side, and then press the gripper into the two sided tape. You can then remove the temporary taped on alignment disc. Additional detail in annotations.

Step 10: Flashlight Sled

Repeat the sled making procedure with wood this time then drill a small hole in the platform face center. Cut out the additional small pieces that make the flashlight support and hot glue together. Insert a screw with any kind of washer into the platform face hole, then slide the flashlight support channel over the screw. Pre-drill two holes into the top of the flashlight support and use metal strapping to fasten the flashlight in place. To test the alignment of the flashlight, slide a piece of paper into the CD case art holder tabs, mark the center and slide sled back and forth. The light should be centered around the marking. The flashlight support channel cut out allows for vertical and horizontal alignment when rotated. Tighten the screw that attaches the flashlight support to the platform when satisfied.

Step 11: Final Thoughts

The part that I had the most trouble with was countersinking the holes into the ¾" pex pipe. The first skis that I made had screws that extended through the hole at varying angles. I had to oversize the CD sled platform holes and it worked fine, but I think we can do better. Next, I'm going to try hot gluing the screws to the pex and forget about countersinking. I did a quick test and it looked very promising.

When I first showed it to a group of friends, I was kinda worried because each person has to line up with the device to get the full mesmerizing effect, but it turned out to make it even more interesting! A few people would be looking from different angles and enjoying the neat patterns, but the person in the vortex beam would exclaim "woahhhhhh!!!" spiking everyone else's curiosity. The viewing zone increases with distance from the machine, but if someone is close enough, you can give them their own private show even if they are surrounded by people.

I took the Rainbow Vortex with me to a festival and this instructable went viral going from 300 to 83,000 views in one day! People loved it and I had a massive amount of fun showing it off. I'm looking forward to seeing the next round of Rainbow Vortex iterations.

Thanks for reading :)