I don't remember putting on any Loctite, maybe I forgot or maybe it comes that way from the factory. In either case, here is how I replaced the EoTech picatinny rail screw with a thumb screw.
First, always check to make sure the rifle is unloaded. Remove the magazine and visibly inspect the chamber for a round.
Using a 7/64 hex wrench, I can't get it to budge by hand and I'm feeling the wrench slip and start to strip the head.
Time to grab a hand drill and a 7/64 hex bit.
Using the bit and drill, I can apply pressure downward to keep the head from stripping.
I'll replace the standard mounting screw with a Yankee Hill Machine thumb screw from Brownell's made specifically for EoTech mounts. It was actually cheaper than getting another replacement hex screw. Plus, I like the idea of it having the slotted head because the chances of me having a screw driver, or something I can use as one, are much higher than having a 7/64 hex key handy.
From there, its just a simple matter of right-y tight-y and bam! EoTech back in place.
Be careful how much Loctite you use!