So yeah the video above is the rig I designed to accomplish two things:
1.) Keep the wrap wire on the spool
2.) Automatically apply the proper tension on both wires to get clean, consistent claptons or fused claptons
It's a pretty simple concept. Any sort of elastic band around the wrap spool can keep the wire from unwinding itself. I used an athletic sock, and poked the wrap wire through the elastic band.
Edit: You also need something to add a little weight under the spool to keep the wire flowing smoothly. All I did was clip my pocket knife to the bottom of the sock.
The stem piece of a old Kanger protank head is the perfect guide for the wrap wire. It has a small hole down the center, and a notch cut out at the other end for your core wire to sit inside of. This isn't the only "guide" device that would work. I was even able to use part of a Kayfun chimney, as well as the top cap to my IGO-W RDA. Anything that gives a rigid path for the wire to follow will work.
I've attached the ball bearing fishing swivels to a loop of 24 gauge kanthal, and rubber band to reduce vibration and give more "feel" to the tension. I looped the rubber band around the base of a heavy house lamp.
This is by all means not the only way to achieve this, just my method. Figured I'd share this so that anyone can get perfect claptons without the practice.
Feel free to ask any questions or to leave comments!