Yellow Submarine Ball Joints
So, I was sitting at my desk a few months ago, searching for random stuff over at Hobby Link Japan, when I noticed these guys from Yellow Submarine - Ball Joint (Kansetsu-Waza) - what appeared to be acrylic, or some sort of clear plastic, ball joints. The short description claimed they held position better than many other joint systems, so I decided to order some, and give them a test drive. I talked to my supplier, and he got me a small lot of them (ten to be exact).
They definitely appear to be acrylic, and come in three sizes - 3mm (x4), 5mm (x6), and 6mm (x4), each joint consisting of a ball and a socket. They are clear, sharp casts, with little to no flash (the only flash I found has been consistently on only one of the smallest sockets - and on the same one in each set - maybe a flaw in the mold? ).
Compared to regular ball joints you might buy from Wave or Kotobukiya, the YS BJ's (Yellow Submarine Ball Joints) are a little harder material wise, and a take a little more effort to cut from the sprues and clean up. They are, however, paintable - I roughed up the surface lightly with some scotch bright, and then sprayed on some primer, and it stuck like a charm. Glues also have no problem bonding to them - I used both super glue and epoxy to hold them in place during testing, and they haven't moved yet. But, let's get to the meat of the review - do they really live up to the HLJ claims, and how do they perform next to regular poly ball joints? Well, to be truthful, the YS BJ's blow normal ball joints out of the water - I tested two normal ball joints - 6mm size - against the same sized YS BJ. I pulled against each one with a spring scale, and noted at what load the joint would start to move. Consistently, the YS BJ's held to ten times the loading the normal ball joints would start moving at. This also corresponds to any twisting motion you may give it - these joints are about the tightest, and toughest ball joints I've ever seen. If you get the chance, I highly recommend getting some, and using them in your next resin kit, or scratch building project!