Permatex and Loctite industrial strength mil-spec retaining and thread-locking compounds anaerobicly cure (absence of air) when the fastener is installed. Colors indicate strength.  Green is the strongest, and it is used for unthreaded surfaces like bearings and cylinder sleeves.  Red is used for the larger bolts over 3/4"; and blue is used for below 5/8" and down to 1/4".