I recently read an article that said epoxy can't penetrate through color fast thread thus making the guide connection weaker and if so is there a way to use color fast thread and get a strong bond for the guide. I like to use color on the rods to stand out and non-cft thread generally gets darker and somewhat translucent.

You wont have an issue with color fast thread. All the epoxy does is protect the thread wrap.
Dan Grulke

The thread provides the bond between rod blank and guide.

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Dan and Tom are correct, and diplomatic too.

I'm curious about the author's source for such a claim as my initial reaction is hogwash. While it is true that finish epoxy adds very little structure strength to guide wraps, the epoxy most certainly does penetrate the wraps, NCP not withstanding. Perhaps the author has never removed a wrap made with NCP nylon and finished with epoxy.

It just penetrates a little less,as NCP thread has a filler component to make it colorfast.

Robert,
You can do an easy test and get the answer for your self.

Take a piece of standard nylon guide thread and do a wrap a few inches long - leaving space between each and every wrap.

Then, take a piece of NCP guide thread and do a wrap the same few inches long - leaving space between each and every wrap.

Then, apply your standard two coats of finish over each of the thread wraps 24 hours apart.

Then, let the finish cure for a week out in the sun or other warm area so the finish will be nice and solid.

Then, do the test where you cut one end of the thread loose and peel each piece of thread off of the blank. If you happened to have a spring scale, you could measure the force required to pull the thread off of the blank.

Repeat for the other thread, also recording the force, or if you aren't using a scale, at least your comparative impression of the force and or difference between forces to remove the 2nd thread.

It would be interesting to all of us, if you shared your results with all of us.

Take care

It is my opinion based on removing a good number of wraps that CP does result in wraps that come off significantly easier than those wrapped without CP - ALL WRAPS WITH REGULAR NYLON THREAD. I have heard otherwise, but I don't believe it. If penetration of the thread by epoxy is prevented it is logical to conclude that the total structure of the "plywood" system will be at least somewhat compromised. Roger is right, if you want the definitive answer, do a test.

I submit his test is designed wrong, though. The proper test, in my opinion, is to do a series of wraps with guides just like you do when building your rods, then both try to move the guides and also nick it to the thread and see how hard it is peel the finish off. The suggested space between the thread wrap is a different condition than wraps tightly stacked.