Zap Z-42 Blue Thread Locker
CAUTION: Threadlocker can significantly weaken plastic, causing parts failure. Do not use threadlocker on wing screws, propeller screws, or any area which is near plastic parts. Use of threadlocker must be limited to strictly metal-to-metal joints, such as the grub screws inside the retract struts, or the screws which connect the motor itself to the metal X-mount.
A dab of blue thread locker will help hold metal screws nice and tight yet they can easily be removed if needed. Blue thread locker is perfect for motor mount set screws, landing gear set screws, retract screws and other high-vibration applications. Do not use on plastic screws or plastic parts. Blue thread locker can cause some plastics to become brittle. .20 oz

Medium strength, general purpose threadlocker.
Locks threaded fastners against vibration.
Parts can be returned to service immediately in most cases.
Parts can be unscrewed when dry if needed.