CA glue is Cyanoacrylate glue. Commonly known as Super Glue or Krazy Glue. It is great stuff for working with the multi-media kits that are produced today or if you use a lot of After Market parts such as resin or PE. Regular model glues do not work very well with materials like brass.
They can be found in most hobby stores with a product called Zap-A-Gap being the most common but there are various other names that it is sold under. It comes in various thicknesses too: Thick, Medium, and Thin. Medium is the one that I use for most of my modelling though I do keep a bottle of thin around for tough seams. Medium is also the one that I suggest for all first time users. Apply it with a toothpick or a pin, it doesn't take nearly as much glue and dries in approx. 15 seconds.
Also great for sticking your fingers to the model.
I personally use it for all of my modelling though I do know others who don't.
Happy Modelling and God Bless
Robert