Making plastic-on-plastic joints tighter

[Whiteraven_2001]

I just won a "grail kit" on evil-Bay of something I had as a kid: "Pancho" the Grasshopper, a Hawk kit of a something on the order of 100/1 grasshopper. When I had it as a youngster, the joints flopped a lot. I was wondering if there was a way to make the joints tighter. Most of them, as I recall, were "pin and socket" joints, but I seem to recall "ball and socket" also. My first thought was coating the ball or pin with some RTV moldbuilder (if it didn't cure too hot) to create something like the joints found in Gundams. Any thoughts, sages of the styrene?

[max142]

I saw in a Hobby Japan along time ago, someone glued a thin strip of plastic to a pin and then sanded the glued strip till the fatter pin fit into the socket.

[Lt. Z0mBe]

To be clear, you're wanting this thing to be poseable? IF that's the case, I would strip a piece of wire, keeping a length of the jacket intact, and epoxy or superglue it to the pin. Or, just replace said pins entirely with CA varnished balsa or basswood dowels.

As for the balls, you may consider some of these:

Poly Unit Ball Joint

Some sets are just the male "ball" ends and some contain ball and socket sets. Again, you'd have to do some surgery, but it would likely give better results.

I hope this helps.

Kenny

[Whiteraven_2001]

From what I remember, the kit ends up laying on its belly with its legs splayed out, because the joints are plastic-on-plastic, so both those suggestions help! I haven't received the kit yet, so I'm basing my question on a 30-plus-year-old memory. I'll be able to diagnose what might work when I get the kit.

[Andrew Gorman]

The classic technique is to paint the joint area with liquid cement, and stipple the areas with a stiff brush- this will tighten them up a little bit. For a permanent fix, graft in some gundam joints.

[Wug]

Save yourself a lot of grief. Build it fixed-pose.

[tetsujin]

Save yourself a lot of grief. Build it fixed-pose.

That would tend to be my suggestion as well. I've spent large amounts of time on various projects, replacing moving parts with aftermarket polycaps and so on, either for looks or for improved mobility - and for what? I don't often re-pose a finished display model, and if there's one or two poses that look really good, it's simpler to achieve those via static-posing mods rather than polycapping the whole thing...

But if you really want to keep the mobility, I would use polycaps. Even if you mod a plastic-on-plastic joint to increase the friction, eventually it will grind itself down again and go slack... Polycaps will continue to hold tension unless they break...

I'd recommend these two types, especially:
Poly Unit T Joint is very versatile and easy to use...
Poly Unit Rolling Joint is a good, compact variation on the basic two-axis polycap...

Both of the above are metric (2mm and 3mm), and both are a bit oversized so you can trim them down to suit your needs... Generally I'd recommend using axial joints for most things. Ball joints can be great in some places, but they can also be difficult to mount and difficult to hide.

There are also various specialized joints that can be really great for certain applications. For instance, spherical hinges, like those used on "Revoltech" figures and so on:
Yellow Submarine "Ball Shape" joint
Wave L-Joint 3

Note that this isn't a ball joint, it's an axial hinge in a spherical package. The exterior of the sphere is (at least in the case of the Wave L-Joint) paintable. It can be quite advantageous to use moving parts that will look OK if they're visible.