Hello all.
This is unuseful topic three.
*I hesitated to upload this topic to "care and maintenance" forum because I think my texts have big problem: I don't know you can find the same materials outside of Japan.
I have used many type of glue to modifying the loose (or floppy) joint.
Insatant glue is popular (but older) method, and it is well known in the players of action figure in Japan.
It makes strong friction. However, it has a risk of jamming. I don't recommend to use instant glue (especially liquid type) without experience of building of model kit.
You must disassemble a joint to applying it.
Fray stopper is not popular method. This material has only a limited effect to keep pose, but it is easy to use and no risk of damage.
You can inject it directly to assembled joint.
White bond is popular method same as instant glue. Last year, I realized this material has two type.
Standard type is used for crafting with paper or wood, and washable type is material for sewing.
Those items make good friction, and easy to use than instant glue.
You must disassemble a joint to applying it in many case.
However, you can inject bond dissolved with water to assembled joint.
Hot (heat?) glue is famous in 12inch action figure owners.
You need some work (drill, curve, or etc) to before applying this material because hot glue needs wider space to make effective.
And...
In the some cases of connecting different maker, vinyl wrap is effective.
If you feel this is useful, I'm so happy.