I spent the last two weeks researching and making endless cassette loop tapes and this is what I learned.

There are many styles of an endless loop tape.

Before starting, I researched the many types of loop tape designs documented on the internet. I really had no idea what I was doing when I started, but I came across a few articles and videos. The idea behind endless loop cassettes, is to create the longest loop duration while using readily available parts.

What is a "Mobius Twist"?

A “Mobius Twist” is when you make a single twist in the tape loop. It will play what you record and then flip over and continue playing, doubling the play time. This truly only works on stereo cassette decks, and not 4-track recorders, although some have reported it creates interesting effects. The audio that plays on the second half, will sound a bit muffled, but should otherwise play.

Helpful Info About Tapes and Tape Players

• At normal speed, cassettes run at 1.875 inches per second.
• At high speed, cassettes runtime is about 1/4 the running time at normal speed.
• Standard cassette players can play and record both sides of a cassette in stereo.
• 4-track cassette records consume both stereo channels, so you can only play one side.

How to Build a Loop Cassette

Materials and Tools needed:

• small screwdriver (for servicing eyeglasses or computers)
• X-ACTO® blade for cutting tape (or a small pair of delicate scissors)
• 24″ ruler (a cork-backed ruler works well)
• a few Post-it® notes
• clear Scotch tape
• cutting surface (I use a thin piece of cardboard)
• Gorilla Glue “Gel” instant-drying glue (Super Glue® or Loctite® glue will also work, optional)
• blank tape(s) -new, or used, blank or commercially replicated. It doesn’t matter. Just make sure they can be taken apart with screws. Hit your local thrift store. Value Village in Milwaukee has them half off on Fridays and weekends.
• extra cassette wheels and rollers (optional) – these can be scavenged from used tapes that don’t have screws. Just bust em up with a screwdriver.

Build Instructions:

1. Get yourself a tape. (make sure it can be disassembled with a screwdriver.)
2. Unscrew the five screws holding the tape case together and pull the tape apart. Save the screws. I use the cassette’s Norelco hard case to store the loose parts as I tear it apart.
3. 

   If you encounter this type of wheel, slice the tape off where the tape meets the rolling surface. You DO NOT want to pop that sucker out.

   Remove the wheels and separate the tape from the wheels. Save the long spool of tape, as this will be the source for making your section of loop. You can use the tip of your X-ACTO® blade to push out the rubber cylinder keeping the tape leader in place OR if you have the kind where the tape runs underneath a section, simply slice the tape off where the tape meets the wheel. (Note: Assembling this type, after popping them off is annoying and you don’t want to deal with that.) I keep the plastic or light paper non-slip inserts on opaque shells, but I prefer the look of the clear cases without them. Some designs may play better with them left in.

4. Measure and cut your loop to the specified length, based on the selected design. Make sure the ends match one another. I cut them straight 90 degree angle, others prefer to cut them at 45 degrees.
5. 

   Use a Post-it note to align your loop tape ends. Make sure to dull the sticky surface on your pant leg first, otherwise it will pull off the magenetic coating.

   Dull the stickiness of your Post-it® note on your pants until you feel it’s still tacky, but won’t pull the magnetic surface coating off of your tape.

6. Stick one end of your tape to your Post-it® so it stays in position, while you match up the second side. Be sure that the natural curve of the tape curves inward.
7. Cut a small piece of transparent scotch tape, just about the width of your tape, and then however long. Using the short side, apply the adhesive tape on the ends of the two ends of cassette tape. Slice the excess tape off, making sure to cut as close as possible, without cutting the tape itself.
8. Wind the tape onto the rollers, according to the selected design. I’ve found that working left-to-right or right-to left, and back-to-front is a good way to start. For designs with many rollers, you may want to work from back-to-front while using the loose tape cover to lightly cover the rollers that are completed and work towards yourself. This helps keep the tape in place while you make the many twists and turns in complex designs. I’ll use the fine tip of the X-ACTO® blade to guide the tape while holding tape in place with the other hand.
9. Reassemble the cassette shell. Use the X-ACTO® blade to guide the tape in the exposed bottom portion if the shell. The tapes can be somewhat slack and they might need a little coaxing as you close the shell. Insert and tighten the five screws.
10. Test the tape. Play the tape in a cassette deck to be sure the loop plays all the way through. If the loop has jammed, it may be too loose or too tight. Remove the screws and adjust the layout of the tape. I find that you sometimes need to move the tape in front or behind those extra little plastic columns inside the cassette shell’s mold, if you have them. If your tape is too long, remove it, find the seam and remove the extra length from that section. Re-tape and reassemble the tape. Test to see if it plays freely. I test both sides, sometimes the tape doesn’t move freely on both sides. I’ll label the working sides of cassettes so I know how they behave when I’m working with them. If your tape is too short, remove the tape and cut a single slice and measure the length. Determine how much longer you’d like to make it and cut a new piece. Once you find a size that works, write it down.
11. After you’ve tested your tape and it’s working to your satisfaction. If you’re re-using a commercial cassette, place masking tape on the record notches so you can record over the tape. Consumer blanks come with these notches intact.

Troubleshooting

• If you’re using extra rollers or wheels and glueing them, you may need to scrape off the small portions if you applied a little too much. Glue buildup can cause unnecessary friction causing the tape to seize.
• Double-check that the tape isn’t pinched anywhere along the bottom.

How long should I cut the length of cassette?

Cassettes run at 1.875 inches per second. If a design you’re copying lists how many seconds the loop is, start there. You may have to cut 2-3 loops before you find the length that gives you the best tension. You don’t want it too snug, but you don’t want it loose either.

When I record loops, they all have an empty gap at the end of the loop

Here’s my black masking tape “band-aid” which blocks the erase head, allowing for sound on sound recording.

In order to create gapless loops, you’ll need to block the erase head from erasing prior to recording. This allows you to do a “sound on sound” recording technique, resulting in gapless playback. I’ve read that some folks cover the erase head with aluminum foil. Instead, I chose to create a three-layer masking tape “band aid” of sorts. Basically, stick three small pieces of masking tape on top of one another sticky side down, then cut a thin strip, the width of the erase head and place it’s sticky side onto the sticky side of the three layers you just made. Cut it down to size and place it onto the tape, pushing it slightly into the tape. Be sure there is no adhesive except for what is sticking to the sides of the shell. The tape should move freely.

Here’s Hainbach’s explanation of sound on sound recording:

Reference Resources & Further Reading

Here are some helpful websites I found while researching how to make cassette loops and the different modified designs others have done to maximize the runtime of your looping tape.

• Dust Breeding: Cassette Looping
• Cementimental.com: The Two Perfect Loops
• Unique and easy way to cover the erase head for sound on sound recording
• Instructables.com: Audio-Cassette-Loop
• disquiet.com/2011/07/10/jared-smyth-tape-loop/
• Of Sound Mind: Wonders of the cassette tape loop, part 1
• Pete Smith: Endless Cassette Loops
• Michael Ridge: Endless Loop Cassettes
• Michael Ridge: Dead Flies Tape Loop
• Sciencemuseum.org.uk: Make Your Own Tape Loop