Also, whenever I'm not sticking plastic on plastic using plastic cement, I always pin the parts.
It's an anoying, time-consuming proces, but you'll regret not doing it if you dont.
If you are unaware of this process: you drill a hole in both parts and stick a bit of metal wiring/paperclip in these.
This will create a sturdier joint that won't break off as soon as the model drops on it's side.
They're will be plenty of good tutorials on youtube on this.