Loc-Tite works great, is available just about everywhere and is not that pricey. They have version that lock the nuts/bolts and versions that are not permanent
It may not be permanent, but it takes a good hold on the wrench to loosen it! For things needing frequent adjustment (like my Zassenhaus) I prefer Vibra-tite or nuts & bolts with nylon inserts.
Besides, ever reach for the LocTite
Blue and get the
Red by mistake? Blow torch time!