I'd argue that the coating systems on both sides of a panel should be of
similar permeability. So, don't glass one side of a panel and coat the other
side with oil or you'll get some very odd (potato chip) contours .
Epoxy sticks tenaciously, but can't stand sunlight for long and doesn't level
out as well as paints or varnishes. So don't think of it as a finish, except
in private places where it will not receive sunlight. . As a binder under a
varnish or paint finish, it's excellent. Two coats are enough. Take the care
to roll & brush it out a smoothly as you can, 'cuz it's a lot of work to sand
flat.
The brand of epoxy will provoke a long religious argument, as will brands of
varnish.
Do use a true marine varnish. If it isn't at least $20/qt, it isn't the good
stuff. The paint store stuff doesn't have either the resilience or the UV
filters.

Donnie Gilliland wrote:

I'm constructing a 10" tunnel hull and am at the point where I need to
seal/finish the interior of the hull before putting the decking on. The
boat is not going to be left out in the elements or used in sal****er but
will be stored indoors when not used.
My question to the group is this, can I use a good grade of spar varnish to
seal the interior or would the epoxy encapsulation be the better choice? (I
plan on using epoxy and fiberglass on the hull exterior).

Any brands of varnish or epoxy to suggest?
Any suggestions?

Thanks in advance
Don