Sounds like a fancy word for "glue"...
I don't use the kits so I will have to look it up to see what comes with it... looking looking...
Ok, I'm reading the online manual. It says it comes with Loctite 638 glue, so I'm guessing that is what this is referring to. The balls and T-sections seem to have threaded holes, with threaded rod that goes into them, so I think this is to stick the rods into the balls so they don't rotate and unscrew when you rotate the joint in the same direction that the thread goes in. With plan rods and holes you would normally silver solder the rods onto the balls, with threads it grips better but can still nrotate so you add something to hold it tight. They say to first clean everything to remove traces of grease, then apply the Loctite to the threads when you have worked out how you want to put them together. It could be they used to supply Loctite but now make their own equivalent and call it "retaining compound", but haven't updated the online instructions so they still say Loctite.
Like Nick said it is glue It is basically to secure the rods to the steel balls to keep it all tight.
I myself bought one of these armatures and was really happy with it the only regret I have is that the hip/ waist section was a fraction too wide for what I was looking for and once assembled you are stuck with the proportions you chose. Due to this I wouldn't just throw it together like a kid on Christmas once you get it, plan out it's use and make sure it fits your characters needs.
Overall though this was a really good buy. Hopefully it works out for you.
oh, excellent! Thanks guys! Yeah, I started putting it together last night, and found out quickly what I could use the glue for. From now on, I'm going to use the words retaining compound when referring to glue at upscale parties. The only complaint I have is one of the foot plates' hinges is really loose, so I'll have to glue that too, and not have a hinged foot, but other wise, I'm pretty happy with it so far.
If you just keep tightening the foot hinge screw, it will bend the metal and you can get it to where the hinge can be animated.