Summary

As I could not find anything out there, I created a silicon sock mold for the E3D Cyclops plus.

Versions

Initially, I used a 2mm thick sock (v1 photos), which covered too much for my taste and is hard to handle for cooling in my dual Cyclops setup.
v2 of the mold uses a reduced thickness of the sock: 1mm. That worked fine for me, although I would guess around 1.2mm could be the real sweet spot. v2 also features linear slope between the two parts of the hotend with different height down to the nozzle. That helps cooling in my case - as I need to direct air along this slope to the nozzle.

Design

The design itself was done with openSCAD (file attached), without much intelligence - I have to admit: There is no provision to free the sock from the mold. Hence, you will have to destroy the walls of the outer part of the mold. I used a flat screwdriver for that (walls are pretty thin, so that is easy).
Also, there is no special provision for the heater and the temperature sensor. So you need to put the sock over the hotend first, before adding the heater to the Cyclops. For the the sensor, you must put it into place before putting the sock on. The wire will fit under it (good enough).
Feel free to fix these shortcomings. :)

Instructions

• Simply print the inner and outer part of the mold (you could use the cutted version, if you worry about the overhang). Make sure you can put the inner part into the outer part of the mold (file if necessary).
• Take a piece of paper and put the outer part on top.
• Fill around 3.5g of temperature resistant silicone (if I remember correctly) into it.
• Put the inner part of the mold into it. The hole at the bottom will align it.
• Wait until the silicone hardens.
• Destroy the walls of the outer part with a flat screwdriver. Remove the sock.
• Put it onto your Cyclops.

Thanks and enjoy!