Caleb sez, "I tore apart components you can find at your local toy store to make a portal gun that actually levitates a companion cube."
I really wanted to make my own portal gun for this. My schedule and my ego fought hard on this subject and ultimately my schedule won. While I feel like I could have built a fantastic portal gun, there’s no way I could have done it in a reasonable amount of time and gotten as nice of results as just buying the portal gun props available at toy stores.
When initially mounted the coil on the gun, I found that the “arms” were far too flexible. I had to reinforce the arm somehow. The option I chose was simply to bend a piece of steel to the correct shape and strap it to the underside of the “arm”.
I made a cardboard model to test weight and size of the companion cube and got the system working on the portal gun.