Nylon will become translucent without CP. Silk will actually become transparent.
The degree of the effect on either is controlled by the thread size, thread quality, thread color, type of finish AND the application of the finish.
The best bet for testing, is a piece of scrap rod blank and real epoxy. IF you don't already have a piece of scrap blank, just buy an inexpensive blank from your vendor next time you order. Almost every distributor in the marketplace has blanks of some type under $10 .. it doesn't matter if it is graphite or glass, whatever is cheap. One blank will last you a VERY long time for testing purposes.
TJ -