ca glue help to prevent graphite chassis's edges from splitting or tearing. One reason, it protects your fingers from getting pierce by woven glass fibres in the graphite chassis.
use low setting ca glue and toothpick to spread out the glue evenly. one layer is enough. two layers for geeks.
Sanding is optional ( I don't do it ).
However, If you hit something very hard, the graphite chassis will crack regardless with ca glue or without ca glue.
On Road : Xray NT1 , RX8 , T4 || Mugen Seiki MRX4-R , MTX4 , MTX3 prospec || Tamiya M03 , M04 || Top Racing Sabre FD2
Off Road : Xray XT8 || Hobao Hyper 8
Radio : Futaba 3PKS || KO propo EX-10 eurus