: Call the manufacturer of your epoxy and see what they say.
: Personally, I wouldn't do it. I don't think that it would make a
: difference in the final product. Pine isn't prone to
: blotchiness, but does have a lot of grain reversals, and shellac
: won't do anything about those. If you have to do something about
: blotchiness I'd use 10% white glue by volume dissolved in water
: as a wash coat, then sand. BUT- the reason this (or shellac)
: works to prevent blotchiness is by sealing the pores, which is
: the opposite of what you want with your epoxy layer. Also- while
: almost anything will stick well to shellac, even dewaxed shellac
: has the potential to be a bit waxy. I wouldn't want to risk that
: either.

: m

I wouldn't recommend washing with white glue. The glue will prevent epoxy adhesion and any spots where there is glue will come out lighter than the spots without glue. You could do a washdown with bleach, but I suggest just going with it and after (a) coating with epoxy and (b) getting some UV exposure I am sure the blotchiness will even out.