How can i make my skateboard really really heavy?

okay so ive had a few run-ins with the cops in my downtown area because there is a no-skateboarding law. the cops are complete and im tired of being talked down to and treated as an in-superior to those s. i want to make a skateboard thats really really heavy so that the cops have a really hard time trying to take it away, but i dont want it to look very heavy. also, what can they get me in trouble for if i just bad mouth them alot while they take the board? i want to make it worth it without getting in too too much trouble. any tips or suggestions on what to say will be greatly appreciated. I'm doing this as sort of a protest against anti skating laws and things like that, Im going to work on getting the laws repealed.