What I wanted to do was to put a dual nozzle (extruder) into the creality CR-10 in order to print ninja flex and either PLA or ABS at the same time
I used a Reprap dual nozzle from ebay: http://www.ebay.com/itm/121704584458?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Infill: 40% (maybe more if needed)
Material: recommended ABS or PTE, or any other material that has a high temperature resistance.
Screws: 5x M3 10mm length and two M3 Washers.
Things to change or Buy:
-Control board used: GT2560
-LCD had to be changed to accept sd card and LCD working: LCD 12864
-Added extra motor for extrusion (placed in back left corner, closest to control)
-Solder cables for two mini fans inside
-solder power for GT2560 from old board