I've used loctite thread lockers for over 30 year in the aerospace industry. If you choose the correct product, they work extremely well. Most of them resist chemicals and moisture very well, with temperatures being the the biggest factor on it's performance.
Genericaly, there are two primary types, pernament (red in color)and an one that is easily removed (purple). There are also some adhesives for use in locking in pins, sleeves and other press fit types of application.
One thing to keep in mind, for high performance applications, red is usually the choice, and holds up experemely well in high torque and vibration environments. But if you used it in a situation where you were bolting to some large bulky object, removal of the bolt could be difficult. This is because application of heat to about 400 degrees will compromise the thread locker allowing removal of the bolt, but if you can not do this, that bolt may break before you can remove it.
The loctite website gives the specific properties of each of their tread lockers.
Lock washers are a good choice for most applications, however they may scar a critical surface, which may contribute to crack propagation. Another thing that sometimes is an issue, is that the washer elevates the height of the head of the bolt.
For troublesome applications, you may consider a nylock type fastener. These have an area milled into a portion of the threads, with a nylon insert installed. These work quite well in most applications and resist backing completely out, even if somehow they become loose. They do not require any special tools and are relatively easy to remove, though you will not be able to spin the fastener with your finger, meaning you'll have to wrench it all the way in. McMaster Carr have these as standard stock items.
Last edited by The Ned; 05/03/2008 7:28 PM.
