http://www.loctite.com/int_henkel/loctite_us/index.cfm

The following is a list of loctite products and the applications for which they should be used.

271 (Red): High-Strength (permanent) - This loctite is to only be used on screws you don't ever plan on removing again. It requires 500F heat to melt it so the part can come loose, so use this product with caution.

Typical Applications: Set screws plugging holes; Vertical ASA bolt; Anything that is going together and never coming apart again

242 (Blue): Removable-Strength - This loctite is best used on any threaded part that you need to keep from coming loose, but want to remove it on occasion to clean it or install another component. It is removable with mechanical force.

Typical Applications: Drop-Forward set screws; other set screws that need to be removed

290 (Green): Wicking grade - This is used for parts that are pre-assembled and need to be locked in place.

Typical Applications: Trigger rod; Solenoid plunger rod


Thread Sealants:

545 (Purple): This is a thread sealant, not a thread-locker like the above products. This is to be used on airline fittings that need a sealant to keep them from leaking. Allow 24hrs to fully cure.

Typical Applications: Air line fittings

592 PST (White Paste): This is the best substitute for teflon tape. It's a paste with teflon that does not dry and is better than teflon tape because it won't tear and send strands of tape into your gun and possibly cause problems.

Typical Applications: Air line fittings