After a laborious session at the sewing machine, the concertina is assembled (in halves) and ready for dyeing. All in all, it went smoothly with less mistakes than I usually make, I think. I only had to rip out a small area of a few seams to allow for insertion of a strip that needed to be under the trim. The paper is relatively thick and very smooth and doesn’t really want to bend gracefully as it goes through the machine in long strips.
The covers were stitched down, with the pockets stitched closed on those ends. The upper edge trim was stitched on. Strips of kozo paper were added to join the sections. Two sections were joined together by these strips, while one strip was just stitched on one side. The rationale for this is that the printing needs to achieve good contact between book and leaves. The book is thicker at the bottom due to the pockets. So the concertina is left in halves at this stage, allowing one half to be bundled upside down to equalize the depth of the book.