Just rewrapped a couple of guides on a rod for a friend and used CP as I like to ensure the trim bands stay put once I've managed to get them done.
Now the epoxy has dried, the thread is a brighter colour than the existing ones and I seem to remember if you dont use CP the thread tends to darken, is that right?
Philip

yes. regular nylon. And become transparent also.

Got the right color ? Try several wraps on a piece of scrap.

Bill - willierods.com

Phillip,
Just for future reference, if you have any question about the final color of a particular thread, do a test wrap. Then, wet it down with alcohol.

The wetted thread will pretty much have the look of the thread after it has been coated with epoxy and then allowed to dry. The difference, is that you can get the look of the final color in just a couple of seconds, rather than going to the time and effort to coat a wrap and then let it dry.

Rod builders have personal preference about thread. Some folks like to have the high color content and apparent thread look that you get with using NCP thread, and or regular uncoatd thread that has been coated with CP.
Other folks like the look of thread that gets well coated with finish that darkens, and tends to become semi transparent. Some folks like to use combinations of this type thread along with some types of metallic thread.

Do some experimenting and decide the look that you want for a particular project, and then use the product that allows you to get that look.

Roger

I know that ncp will darken when finish is put on without cp

Also, perhaps the other guides finish has darkened over time?

NCP does not darken without CP. I often use regular nylon for my main wraps and trim with one or two bands of NCP. I apply finish to my wraps without CP and the nylon transluces, while the NCP stays the original color.