Hey im gonna start to make a RGB proton pack and i was wondering what color blue or black ??? and also what is another material i can use beside wood that is easy to get and is cheap???

I'd use a mid to dark blue for the color. If you're looking for a light weight matirial that's cheap and easy to build with, you gotta go with Foam Board! It's just a piece of foam with paper on the sides, but it works great! It's around $1.95 a sheet and you can get it at places like Hobby Lobby and Micheals (Even Eckerds sells it!). It comes in various colors and you get either thick or thin. I'd go with thin. Hope this helps.

-Autsin

Go for a mix of blue and black in certain places.