re: Starting to finish

Plaster of Paris makes a great filler if the substrate is stable. For knots it’s perfect because you can thin it to a very soupy mixture and it will still cure. Plaster of Paris is not like joint compound. It cures in a chemical process, not just dry out like joint compound. Once you prime over it, it’s good for life. I always use BIN shellac primer on the doors and frames because of the knots. It keeps them from staining through. It’s also the best primer/sealer you can buy, which helps keep the moisture level even.

I even use plaster to fill small gaps at the tenon shoulders. This works out pretty well, meaning that in all the doors I’ve made so far, none of the plaster filler has ever fallen out but the M&T joints do open up a smidgen sometimes. The end result of those situations so far (and remember there are a few that are a couple years old now) is that you see the joint instead of it being completely 100% smooth (no visible joint). So I’m still OK with that. It adds to the character.