Your most dependable thread locker

[Hugger-4641]

If you really don't want medium to large sized bolts to come loose, I'm talking m4 and up, Loctite 263 has been my choice. If used sparingly it usually doesn't require heat, but on smaller bolts it's a good idea to use a little heat to keep from stripping the heads.

For scope bases and internal screws that will be exposed to oil and solvents, 243 is my goto. No heat required, but a little contact with a solder iron doesn't hurt to make things easier.

 

[adk hunter]

I've had to google four things from this thread!
"Sentient" being the most interesting...

 

[Barrelnut]

I don't like anything like loctite or oil on scope and receiver threads, because they alter torque readings. I clean the threads threads of both screw and hole with brake cleaner or denatured alcohol to remove all grease or oil, then torgue the cleaned and dry screws. Afterwards, I seal the sides of the screw head to base or ring with fingernail polish or blue loctite. Nothing ever moves, but if it did the broken fingernail polish seal acts as a witness mark and you can visually verify that something changed.

 

[2buffalo]

Paint pen.

 

[Jon Bischof]

Another advantage of Vibra-Tite is that I no longer need heat to break ring screws free. And after switching scopes you just screw it tight without having to clean the screws. The Vibra-Tite still holds firm.

 

[Turpentine21]

I've never had to heat anything where I used blue loctite or Honda bond and torqued to manufacture specs. Usually between 18 to 25 inch pounds. I also clean all thread surfaces with denatured alcohol before applying and use threadlocker sparingly