- 4 inch carriage bolt
- 2 ea matching nuts
- 2 ea metal plates (electrical box covers work well)
- Black and white duct or Gaffer’s tape
Drill a hole slightly larger than the diameter of the carriage bolt through the center of each metal plate. Thread the first bolt all the way on to the carriage bolt. Cover one side of each of the metal plates, one with white tape and the other with black.
Whether your are using white foam core board as a reflector or black foam core board as a light absorber punch a hole through the center of the board large enough for the bolt.
Slip the non-matching plate onto the bolt, put the bolt through the hole in the board, then slide on the matching plate with the taped side visible. Thread on the other nut and tighten by hand.
Now slip the non-threaded side of the carriage bolt into the gobo head of a c-stand or gobo arm and tighten to hold in place.