You taklin' about zinser bin shellac(clear), or zinser bin primer(white)?
I used the shellac on some of the first plugs I built. seemed ok, but I decided to strip 'em down, make 'em purty and seal them with the usual linseed/spirits a few months later after the toothy critters got to them, and the epoxy cracked here and there, I would imagine due to the wood swelling, and a poor seal.
they were moldy in places
the primer I have used just as primer, but only after sealing, so no real comment on that.