Tape Pixel Core
The LED strips will need to be affixed to the pixel core. I used double-sided NITTO tape to adhere the back of the flexible PCB from the NeoPixel strips. I applied short strips of tape across the cylinder in a staggered pattern. I found NITTO tape has a strong hold and doesn't leave behind residue.
Secured NeoPixel LED Strip
The placement of the LED strips needs to be considered and planned. The top and bottom halves of the geodesic sphere ought to have a linear flow – data in flowing to data out. The assembly in this photo shows the bottom half. The long cable connects to the very first neopixel strip and will feed out the bottom of the geodesic sphere. The strip wraps around the cover in a clockwise direction.
The second LED strip is attached to the second pixel core cover using more NITTO tape. Adhere the strip so that it follows the same direction of data flow as the first LED strip. Position the first pixel (with soldered cable) near the bottom of the cover and wrap the rest around the cylinder.
Double NeoPixel Cores
Here are the two neopixel strips laid out in the proper arrangement. The beginning of the chain starts on the left with the first neopixel connecting to the longer cable. The last pixel on that strip connects to the first pixel on the second core. Note the data flows in a consistent direction across both strips. (The core on the right side actually has a medium-density neopixel strip which was left over from prototyping).
Take this moment to adjust the arrangement of the neopixels. Check and ensure the strips are adhered to the cylinder. Are the connectors able to plugin across the two strips?