After the joints are cut they are final fitted. The bottom patterns and sealed prior to assembly, as the panel will grow and shrink in width (across the grain) with the seasonal humidity changes. By prefinishing them, when they shrink there won’t be a “witness line” that shows where the finish wasn’t applied to the edges of the door inside the dados. Epoxy is applied to all edges of the joints and the dominos. Clamps hold everything tight and aligned until the epoxy cures.