I'm new to relatively new to weaving and have started a rep weave rug (wall hanging? really fat runner?) and am trying to find BLACK rug filler. Does it even exist? In lieu of something commercial, I am prepared to ply some yarn to make my own. Has anyone ever done that? Seems like it would work. I don't like the use of fabric strips -- too messy. I want a clean look.
The Lunatic Fringe carries 4/8 Repp Filler (384 yd/lb) in a number of colors, including black. If that weight isn't thick enough to weave as a single strand, you could double it, which is where you wind two strands together (they aren't plied together) around a ski shuttle, stick shuttle or rug shuttle. Using a boat shuttle for doubled yarn isn't a good idea, because the one strand always seems to feed off longer than the other.