This is how it goes with the colors

Purple for small fasteners. I have not had much luck with this on my nitro vehicles.
Blue general purpose this is what I use and have the best luck on my nitro vehicles and this is what most use.
Red bearing retainer. Not for RC vehicles!
Green sleeve retainer. Sure not for RC vehicles!!!!!

I have been a motorcycle mechanic and machines for over 30 years. The only thing that will get loctie to break loose is heat on the stronger stuff. Like I said I use a REAL small torch. Some times I even have to use it on the blue.