For film, we make very realistic fake barbed wire this way:
Use a 16 gauge standard insulated solid core copper electrical wire(The type used in household wiring, from HD or Lowes)
Cut 1 piece about 215% longer than you desired finished length (Make it longer than you need, you can always cut it shorter)
Drive a nail in a block of wood or clamp a nail in a vise
Fold you wire in half and take the loose ends and tighten them in a cordless drill chuck
Loop the other end around the nail, pull tight and wind the wire using the drill motor.
Look at a photo of a rear piece of barbed wire so you can get the amount of twist correct.
Using bulk rubber O-Ring cord stock rubber (available from
McMaster-Carr) about 1/16" in diameter. (Don't try to use actual O-rings, the circular shape will be a problem)
Cut 1
1/2"- 2" lengths and cut the ends on a diagonal. Do a test to see what is the correct length to look like the "Barb"
Wrap the cut pieces of o-ring rubber around your twisted electrical wire about 2 times and glue with super glue. Again, look a a real piece of barbed wire to see the correct wrap number and the spacing of the barbs.
Now paint- either silver or you can add ruddy brown primer to give it a rusted look.