Building a Portal Turret with motion controlled audio and lighting

Step 3 Making the Masters - Arm and Legs

While I was making the body I was also working on the arm. Since I will be making a mold of this, only one master arm is required and I'll then cast it twice for the left and right side. The arm was built using a similar method to the body. I started out with a foam base and attached wooden plates for the 2 flat portions on the inner top and bottom sections. The outer surface was just covered with lots of Bondo and sanded to achieve the curved surface I needed.

The inside of the arm was formed by creating a template of the arc and using it to form the Bondo while it was still malleable. The hold for the gun box was cut out with a Dremel.

The entire arm then went through the same process as the body, and was primed and sanded until it was glassy smooth and ready for molding.

The same general techniques were used for the remaining parts. The 4 leg pieces started as blocks of wood and were shaped appropriately the a belt sander and hand sander. I found carving these straight from wood was a much faster technique than starting from foam, coating them in resin, and refining the shapes.

I only made one long leg piece to be cast 3 times, with the front two legs cut to the shorter length. I also made a single gun box to be cast twice.

That covers all the main pieces I will need to make a full turret. By the time I had finished the body, arms, legs and gun box, I lost count of the number of cans of primer I had gone through. It was seriously a lot of primer.

By this point my garage now has a nice thick layer of dust on absolutely everything! I'm really looking forward to having to clean it all up at the end of this project.



Materials used for this stage
MDF (medium density fiberboard)
styrofoam
Apoxie Sculpt
bondo
primer
wax

Tools used for this stage
Band saw
belt sander
hand sander