How do you make a cast for broken bones?

Question: How do you make a cast for broken bones?
- Keywords:
  bone,
  break,
  cast
Asked by Dman456 to Ivor on 23 Feb 2018.
- Ivor Geoghegan answered on 23 Feb 2018:
  
  Usually, you set the bone and then make a cast from a material called plaster of paris. It is a special bandage and you add some gloopy liquid and then it sets hard. You want the cast to be hard to make sure that your bone doesn’t move around too much while your bodies fixes it.
  There is some new research into making a 3D printed cast. This would be make from a type of plastic and have many round opening all along the length. This means more air would get to your skin and hopefully, it would be less itchy than regular plaster casts.

Question: How do you make a cast for broken bones?