I have made it by taking fishing line and tieing knots in it. Cut the knots so a little sticks out for the barbs. Then you can spray paint black and weather it as you would like. If it is new just paint over it silver. For older barb wire Spray paint black and add some rust coloring to it. This might be a little bigger than scale but for the most part shouldn't be to bad or at least most people that have seen mine don't notice it.