Chapter 18.2 - The Secondary Pouchboard
The secondary pouchboard is exposed to the atmosphere, right out where the pouches might be destroyed by vermin, and where some mender can get to them and try to "fix" them. First the few remaining cups were removed. Ignore the complex method described a famous early treatise on Orchestrelle rebuilding. Kevin McElhone advised, and I confirmed, that merely giving to old cups a light tap with a small hammer, shears the hot glued "peg joint" between the cup tenons and their holes. Then the cups can be plucked out easily, in one piece. But most of my cups were already broken off, and many of them were lost altogether. Some early mender had replaced some of the pouches (using thin sheepskin!) or had merely patched the pouches with bits of skiver. But he used white glue for this. If pouches are set with hot glue as they should be, a simple wipe down with hot water removes the old pouches neatly, leaving the board surface intact. So I had to scrape and sand the pouchboard surface. I vowed to avoid using sandpaper on any critical surfaces in my organ, but it could not be helped in this instance.
The shellac lining of the pouch wells and passages was refreshed with new shellac, brushed on then wiped off the gluing surface with an alcohol soaked paper towel. Shellac was injected into the passages with a disposable glue syringe and a pipe cleaner. Then the 3/8" holes for the cups were whiffed out with a drill to make a new bare wood surface for gluing in the new cups.
The new pouches are laid with hot glue, adjusted rather longer (thinner) than is usual for gluing cloth. I can't just brush the glue on to the pouch rim without getting some in the well. It is easier for me to dab ai bit of glue around the rim, and then smooth it with a circular motion of the finger. If the glued area is shiny, but not smooth like a thick pool, it is just right. One has to work quickly, but pouch leather is one of the few materials that will stick to hot glue even though it has started to cool down.
The pouch circle is then laid flat on the glued surface, and then "set" with a dipping tool. Mine is just a wooden disk with a 1-1/4" valve disk screwed on. It is important to push the dipping tool down hard, so that its rim firmly holds the edge of the pouch to the board, while the center pulls the leather evenly towards the middle.
After a few second to allow the glue to set, blow into the pouch. This makes sure the pouch is firmly adhered all around its edges. At the same time this unsticks the leather from any point that it may have become stuck to a stray bit of glue on the wall of the pouch well, so the pouch is fully flexible across its entire area. Go ahead and blow as hard as you can. If the pouch is imperfectly adhered and comes off, it is better to know about it now, and start over. But this rarely occurs; briefly set hot glue has an amazing power to grip leather with immense strength.
Stick a 3/8" dowel into the cup holes as a guide for the knife, and trim off the bit of the pouch that laps over the hole.