It started out as a board of foam core with chip board built on top of it. I used Modge Podge to seal and prime it and then used a flat acrylic black paint and added a little weathering technique to give it a realistic look. I used various pieces of bass wood for the strap and belt harness as well as for the hook that attaches the gun to the proton pack. All together between cutting and gluing, painting, and tweaking here and there only took a month and a half; working some nights and weekends.
The overall design was a combination of the cartoon, action figure and movie proton pack. For the most part I improvised throughout the whole construction process because I was not sure in which direction I wanted to go with as far as the design aspect. I aimed to keep it simple yet believable by meshing various designs based off pictures from books, comic books, internet, and old toys I dug out of storage (yes I still kept them all).
Hopefully one of these days I would like to incorporate some battery operated light effects onto the proton pack just like in the movie so I can really stand out at the clubs that are hosting costume contests for Halloween.