I routed the design out of half-inch MDF. I cut two of them in case I didn't like how the first one came out.
After sanding the edges down to get a smoother and more realistic look, I started working on all the add-on pieces. For the fretboard, I found a piece of thin wood laminate that I cut to the basic width of the neck then sanded it down to an exact fit. I measured out the frets and used a Dremel to route the channels where the frets would lay. The frets were cut from a thin steel rod.
Next I cut a back plate from 04 aluminum and drilled holes to attach the neck to the body. The pickups were made from black acrylic. I used two small nails for each pickup which gave me a way to attach them and the nail heads added a realistic look. I then cut a piece of 02 styrene into the shape of the pick guard and cut holes for the pickups and marked screw holes.
The fretboard was then stained and then glued to the neck and the steel frets were glued in the channels. I found some knobs, small screws, and random hardware to stick on. Next I painted and gloss-coated the body of the bass then reassembled everything. Lower guitar strings were strung which worked as scaled down bass strings. Lastly, a strap was made from the leather of an old belt and a mini chord made which can be plugged in or out as needed.