For my application I am using it on metal to metal . I am only concerned whether it will cause the plastic servo arm to deteriorate over time because I am sure the threadlock will wick into the servo arm hole . I will use medium c/a instead. BTW Loctite 425T ( Assure surface curing threadlock ) is supposed to be compatible with plastics .
http://www.ellsworth.com/display/pro...5&Tab=Vendorss