The wrist cylinders on my 20th Anniversary DVD edition Optimus Prime have become a bit floppy . Will a light coat or two of clear nail polish tighten them up?
After inspecting the piece in question I gotta say it's a tricky fix, try the clear NP on the 2 gray cylinders where they connect to the hand BUT...there is almost no space whatsoever to accommodate a coat of clear NP. It might be better to add some aquarium sealant or shoe goo under the 2 gray cylinders where the top of his blue "wrist" is. When dry the rubbery product should act as a "brake" and restrict the movement of the 2 gray cylinders. Good luck !
Ya bro ! ... http://www.eclecticproducts.com/shoegoo.htm It's a clear rubbery compound when dry.(much like aquarium sealant)