It is essential to blue loctite at least every screw fitting in metal. The manual is not consistent with this! I used blue loctite in about every screw, even many of the ones fitting into plastic. Loctite can craze some plastics, but the main frame plastic of the raptor is not sensitive for loctite. Some people recommend to use CA (cyano acrylate = 10 seconds glue) for metal to plastic connections, but with loctite you can remove the screw if you need to later. You can remove CA-glued screws by heating them (for instance with a soldering iron, a pencil torch or by heating up the tool that you use) but probably only for metal-in-metal screws as plastic will melt. For metal in metal, CA will fasten very tight and within 10 seconds, so you have to screw the bolt in within a few seconds.
It is extremely important to degrease the bolt and nut before applying loctite (or CA), especially if you reuse old screws. Otherwise the loctite will not work properly and the stuff will vibrate loose anyway. You can use benzine for degreasing.
I put insufficient loctite in one of the tail rotor hub screws, and the screw vibrated out already on the second test run. We heard a "plop" and stopped to see what happened. This was left of my tail:
A number of people searched the area at least 40 meters around the heli, but did not find the tail rotor. Imagine what would have happened if it would have hit someone! The rotor was found weeks later, after the grass was mown.