The palladium ring–a roughed up copper wire ring painted with a thick, blobby mixture of aluminum paint to look like a cast piece of palladium.
Matches the movie piece pretty nicely…..
Needed a gear-like device with 200 teeth, so built that from styrene triangular stock and flat stock….one tooth at a time….
Not too painful. About two hours of work under a magnifier.
Now the circuitry layer–I mined a couple old computer motherboards I had for interesting looking pieces (chokes, larger electrolytic capacitors and diodes) then built a chassis for them. These are mostly hidden, but closer inspection of the arc reactor shows the inner detail even though the movie prop is never seen that close.
A little more brass paint and fake solder (chrome paint).