: . . . Lastly, any suggestions on what to do for a flat white tough UV coating...? I
: wish I could just leave everything the final flat white this stuff comes
: out with, but worried about the Epoxy degrading...

If you are using the HBN, or similarly, graphite, as a final coat on your hull because you want reduced resistance, or impact resistance, then that had better be your final coat. Putting anything on top of it would cancel any advantage you hope for. Here is an analogy. Think of putting great bearings on your roller skates, and then covering the wheels with a layer of concrete for "protection" It would keep those wheels from spinning at all!

The exposed crystals or bits and pieces of graphite or HBN have to be the material that makes contact with the water, or the rocks.

Hopefully the HBN itself blocks enough light to protect any epoxy under it from a lot of the UV. Graphite certainly does that. With a bit of "weathering" you'll eventually lose a tiny amount of the coating, and expose a fresh layer of the underlying HBN. This is similar to the ablating copper-bearing paints used on the hulls of larger boats. Eventually enough of the coating wears off and you apply a fresh layer.

Just think of this as normal maintenance. You may need to do it every year, or every five years. It depends on how much you use the boat, and how you store it between uses.

PGJ