Hello, just a thought but looking at your previous builds they seem to be static models? On that basis can I suggest you have good think about glues etc. They need to be good joints and not just a tacked together joint. Working models are moved about, transported, inadvertantly knocked. All these things happen.
Also wood treatment needs to be not only waterproof but able to resist a damp environment. Wood needs to be varnished / painted and not left exposed on the inside, where of course it would never get wet. Trust me it will!
best of luck
Roy