I have a large spool of Gudebrod NCP "A" thread. I would like to use it on a couple of rods with a metallic silver trim ring. What will be the effect on the black NCP if I use color preserver to coat the metallic trim? Or do I really have to. I know some people do not use color preserver, but I always have.

You don't need to use CP on either. Just wrap, pack, and finish.

You only need CP if you need to preserve the color of a lighter color nylon on polyester thread over a dark blank. Neither NCP or metallic threads need color preserver.

You don't need the color preserver but if you apply it it won't hurt anything. I usually buy NCP thread in the light colors (cream, white, yellow, etc) and will wrap with NCP and non-NCP thread applying color preserver when done. No problems.

Thanks Guys. I probably have more black ncp thread than I will ever use.

You can use that thread for all those little loops you go through for tieing off thread