Great job.  But why the warning about covering graphite power?

Interesting, but several areas are a bit dubious. First, as Gene asks, what's wrong with finishing over graphite/epoxy mix? Nothing. The only reason not to do it is if you want the slippery finish which helps prevent scratches. Because of the graphite, that part of the paddles don't need  UV protection, so they don't need a finish, but there's nothing wrong with applying one anyway.

Next, the lack of finish on the paddle blades. You can get away with leaving wood and epoxy unvarnished for a good long time because the wood's internal structure can provide strength as the epoxy deteriorates from UV exposure, but not for a CF/epoxy layup. Those paddles should really be varnished for UV protection.

Finally, with CF layups the epoxy choice is much more important than for wood/glass sandwiches. The epoxy needs to be a high modulus one, like System 3 Silvertip. If the layup is not going to be painted, the epoxy needs to be one with a higher temperature softening point, so that it will retain its full strength in strong sunlight.The pros typically use a high temperature cure epoxy which gets cured in an oven for parts which stay black.

Laszlo

Planning to build a similar paddle using vacuum bagging and twill carbon cloth. For stuff like this I go with the S3 SB112 epoxy because it has a UV protection already in it. I still plan to varnish over it so the finish will match the wood.

Post pictures.