"Glenn Ashmore" writes:

I would seal it to get a final moisture barrier outside the microballoons.

When building my boat I painted (2-part LP) directly on the
fairing compound and as far I can see it works just fine.
My boat enters its 20th season right now.

http://hem.bredband.net/b262106/

--
Martin Schöön "Problems worthy of attack
show their worth by hitting back."
Piet Hein