Theoretically it sounds really easy; you can make a tape loop by taping the ends of a short piece of magnetic ribbon together and sticking it back inside the cassette tape. However, if you ever actually tried to do this, you will soon realize that it is a tad bit trickier than one would think. I spent an afternoon working out and refining this science. After many tries and many, throw-my-hands-in-the-air-and-promise-to-give-up sorts of moments, I think I have it down reasonably enough to write instructions for someone else to do it. Now you too can tape the ends of magnetic ribbon together, ?, and profit!
Step 1: Go get stuff
You will need:
A rubber washer
A razor or craft knife
Clear packing tape
A cassette player
Step 2: Open the case
Open the cassette tape by removing the screws. Carefully set them aside for later reassembly.
Step 3: Remove the reels
Remove the tape reels, but don't disturb any of the other mechanisms.
Step 4: Prepare the reels
Cut both reels free from the magnetic tape.
Put your rubber washer around one of them. This will be the wheel which will pull the tape.
Step 5: Cut some magnetic tape
Cut a section of magnetic tape roughly a foot long.
Step 6: Thread
Position your wheels back inside the tape and thread the magnetic ribbon around the rubber wheel, under the unmodified wheel, around the pulley opposite the rubber wheel, through the channel at the bottom of the tape, around the other pulley and also to the right of the plastic peg (next to the pulley).
In other words, just look at the pictures.
Step 7: Tape
Apply a small piece of double-sided tape on the inside of the magnetic ribbon, pull the loop tight and tape it evenly together.
If the magnetic ribbon is attached at an angle or any tape is sticking off the sides, your tape loop almost assuredly will not work.
Step 8: Washer
Cut a washer out of mat board and stick it on the inside of the case around the opening that lines up with the wheel with the rubber on it.
This provides more pressure on the sides of the wheel and ensures the wheel will spin. I found this to be necessary.
Step 9: Close the case
Trim away all excess magnet ribbon and close the cassette back up. When reinserting the screws, only tighten them about 80% on the side with the rubber wheel. Readjust tightness as necessary until it plays correctly in your cassette deck.
Step 10: Now make it better
Perhaps that first loop you made was a little glitchy and you would like for it to work better.
There is an easy way to do this.
First, reopen the case, remove the magnetic ribbon loop and cut it in half anywhere along its length.
Step 11: Make a new piece
Carefully measure this piece of magnetic ribbon and then cut yet another piece of that exact length.
Step 12: Splice
Take a small piece of packing tape and evenly splice together the two ends to form a solid band (without any twists in it... although, if you put one twist in it, it will double the length of the loop, but make it harder to reassemble).
Trim away any excess packing tape with your razor or craft knife.
Step 13: Putting all back together again
Install the new band of magnetic tape into the cassette deck.
Reassemble the whole unit once more and enjoy your cleaner sounding tape loop.
I always assumed that the tape wheel was the mechanism feeding the tape through the player and because of this, I thought that the magnetic ribbon had to be highly tensioned and the wheel needed to be as loose as possible to spin freely. However, what I discovered is that what is really feeding the magnetic ribbon through the player is a little rubber wheel that comes up from the bottom when you hit play. Because of this, it is beneficial if the ribbon has a little slack (less tensioned) and the wheel is a little compressed with sides of the case. Figuring out the right ratio takes a little trial and error.