I build a TCSS thick-walled 1" blade with neopixels. I used clear 1" thick-walled tubing. TCSS Strip Diffuser. TCSS V2 foam. 3535 strips, clear 1/2" shrink and cellophane wraps. I basically made the pixel strip so that they were tight into the foam, and that the foam was wrapped with cellophane until it was tight going into strip diffuser. I did this to insulate the fragile strips as much as possible from impacts of the blade. I also hardened the wiring to the neopixel strips and to the TCSS adapter. I built this blade specifically for this test.
In testing, I used my Dark Force Custom Sabers Transcendence, which is installed with Proffie 1.5. I also insulated my proffie for the test. This is a very tough hilt, and a very tough blade. I did use packing tape on the blade tip to make sure it didn't come flying off.
Disclaimer: DO NOT TRY THIS WITH A THIN WALLED NEOPIXEL BLADE, this blade was specifically built to be tough, and is thick-walled.
Neopixel blades can be built to be tough, it just takes a bit more effort. This blade is fairly heavy in weight.